The Use of Film Badges for Personnel Monitoring

The Use of Film Badges for Personnel Monitoring
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The Use of Film Badges
Personnel Monitoring
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The following States are Members of the International Atomic Energy Agency:
The Agency’s Statute was approved on 26 October 1956 at an international
conference held at United Nations headquarters, New York, and the Agency
came into being when the Statute entered into force on 29 July 1957. The first
session of the General Conference was held in Vienna, Austria, the permanent
seat of the Agency, in October, 1957.
The main objective of the Agency is “to accelerate and enlarge the contribu­
tion of atomic energy to peace, health and prosperity throughout the world” .
I A E A , 1962
Permission to reproduce or translate the inform ation contained in this publication may be
obtained by writing to the International A tom ic Energy A gency, Kamtner Ring 11, Vienna I.
Printed in Austria b y Paul Gerin, Vienna
May 1962
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b y D r. M a r g a r e t e E h r l i c h
V IE N N A 1962
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IAEA, VIE N N A, 1962
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Previous Manuals in the Agency’s “ Safety Series” (particularly Nos. 1,
2, 3 and 4) have made or quoted various recommendations regarding the
use of photographic film in personnel monitoring. The present Manual
offers a much more exhaustive review of the subject for use as a guide
to the implementation of those recommendations. Dr. Margarete Ehilich,
of the United States National Bureau of Standards, wrote the Manual as
a consultant to the Agency. The author alone is responsible for the views
expressed in this Manual.
Like the earlier publications in the “ Safety Series” , this Manual will
appeal primarily to persons working with radionuclides, whether natural
or artificial. However, the principles of photographic personnel monitoring
apply to any kind of ionizing radiation, regardless of its source, and are
applicable by users of X-ray machines, neutron generators or particle
The Manual contains a large number of references to the literature,
including relevant national and international recommendations. Since such
a large amount of literature is already available, the material has been
handled selectively with a view to including mainly information not pre­
viously collected in a form suitable for the present purpose.
May 1962
Director General
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-Chapter 1.
C hapter 2.
I N T R O D U C T I O N ............................
AN D C O N C E P T S ..................................................................................
Photographic F i l m .........................................................................
Latent I m a g e ..................................................................................
Latent-Image Fading
Photographic Processing,................................................................
Reciprocity F a ilu re.......................... ..
Optical Transmission Density
Characteristic (or Hurter and Driffield) C u r v e ....................
Photographic Sensitivity.....................................
C hapter 3.
Energy-Dependence of Photographic Sensitivity
for Charged Particles........................................................
Energy-Dependence of Photographic Sensitivity
for Photons and Uncharged Particles ....................
Quantity to be Measured
........................................ . .
Calibration of Photographic Film or Film Badge . .
The Film Holder . .
. .. .. .16
X - and Gamma-Radiation...............................................
Beta-Radiation, Monoenergetic Electrons
.. ..
Mixtures of X - or Gamma-Rays and Beta-Rays . .
Neutrons in Mixed Radiation Fields
Choice of Emulsions (F ilm s)....................................................... 23
Identifying the Film and the H o l d e r .....................................
Avoiding the Influence of Latent-Image Changes . .
. . 24
C hapter 4.
........................... .............................24
Precautions in Storage and Shipping
Processing........................................................................................... 26
PERSO NN EL-M O NITORIN G S E R V I C E ...................................... 28
Space Requirements
................................................................ 28
Equipment Requirements
....................................................... 29
General-Operations A r e a ...............................................29
Films and Film Holders
...................................... 29
.................................................................. 30
Percussion Press
...................................... 30
Record Storage.................................................................31
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The Calibration A r e a ......................................................32
X - and Gamma-Rays from around 30 keV to
1 MeV and a b o v e ........................................................32
Beta-Radiation (Electrons)
N e u t r o n s ......................................................................... 36
The Darkroom
Location and Design
Film-Processing Holders
Film-Processing T a n k s ...............................................37
Temperature Control
Processing Chemicals
Film Dryer
C hapter 5.
Manpower Requirements
......................................................... 39
1 - a ............................................................................41
First Example
............................................................... 41
Second E x a m p le ............................................................... 43
Third Example
............................................................... 46
1 - b ............................................................................46
First Example
............................................................... 46
Second E x a m p le ............................................................... 48
1 - c ............................................................................53
........................................................................ 53
2 - a ....
2 - b ............................................................................60
First Example
Second E x a m p le .......................................................
. 64
Third Example
Fourth E x a m p le ................................................................71
Fifth Example
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C h a pter 1
Photographic film is fairly inexpensive and durable and, as a result
of irradiation, its radio-sensitive components, the silver halide crystals,
undergo relatively permanent changes. With proper calibration, the optical
density of the developed and fixed photographic film can be related to
radiation exposure. The optical density is not altered by repeated evalua­
tion procedures and does not change grossly with storage over a prolonged
period. For this reason, photographic film is, in some countries, accepted
as medico-legal evidence of radiation exposure.
For personnel monitoring, photographic film is, as a rule, carried in
dental-size packets, contained in suitable holders. Such holders, containing
packets of photographic film, are now often referred to as “film badges” ,
regardless of whether they carry personnel identification such as photo­
graphs, passes, etc.; i. e., regardless of whether they are complete identifica­
tion “badges” .
Personnel monitoring with photographic film is today the method of
choice in many laboratories [1], although it requires a certain amount of
apparatus for film calibration, processing and densitometry, as well as a
conscientious technical staff. Photographic personnel monitoring is particu­
larly recommended where it is important to increase the awareness of
radiation hazards among radiation workers, health-physics experts, and
administrators, and, at the same time, alleviate unwarranted fears, but
where no need exists for distributing routinely a large number of delicate
radiation instruments requiring a considerable amount of maintenance
(such as, for instance, pocket ionization chambers and pocket dosimeters
of the ionization type).
Where frequent changes in the working routine make it desirable to
provide for an immediate determination of exposure dose, either by the
individual himself or by the health-physics expert in charge, it is often
recommended that film badges be supplemented by pocket dosimeters
of the ion-chamber type. (For an explanation of the difference between
pocket ionization chambers and pocket dosimeters of the ionizationchamber type, see, for instance, the IAEA publication “ Safe Handling of
Radioisotopes” [2].)
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Pocket chambers and pocket dosimeters indicate exposure dose without
any previous processing, as is necessary for photographic film. They do
not have to be calibrated each time they are used, but require only
occasional calibration checks. They should be submitted to regular expert
tests for malfunctioning, spontaneous leakage, etc. Recharging the instru­
ments for use destroys the primary record of radiation exposure. In fact, in
most pocket ionization chambers, which, for reading, have to be coupled
to an electrometer circuit, the mere process of reading alters the exposure
indication. Recharging requires considerable care.
Experience has taught that a film-badge service works more efficiently
for a larger group of people, say, for a hundred or more persons, than for
five or ten. Therefore, it is often recommended that a centralized service
be run for a number of individual laboratories. The monitoring centre
should be located close enough to the individual laboratories for an occa­
sional personal contact in case of doubt regarding an exposure assessment,
or in case the necessity arises to advise a worker, or the health-physics
expert, of a potential radiation hazard.
In the following chapter, a review is given of the more common photo­
graphic terms and concepts of importance in photographic dosimetry. In
the third chapter, the application of the photographic technique to per­
sonnel monitoring is discussed. The last two chapters deal with problems
of a more practical nature, of importance to the person who is actually
establishing a film-badge service: in chapter 4, space, equipment and
manpower requirements are presented, and in chapter 5 specific examples
are given of photographic personnel-monitoring procedures, as they are
now carried out in existing monitoring laboratories.
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C h apter 2
Photographic film:
An acetate or plastic base, covered on either one or both sides with
a light-sensitive gelatinous layer (the emulsion), containing small
silver halide crystals (grains). The films usually used for personnel
monitoring have a high content of silver bromide; their grains are
fairly spherical and, as a consequence, the energy loss of ionizing
radiation within the emulsion is relatively isotropic.
Average diameter of undeveloped grains: 0.1 [xm or less, to 1 jim,
according to film-type used (lower limit corresponding to nuclear
Emulsion thickness: according to type, 2 to 5 X 10~3 cm.
Latent image:
A microscopic aggregate of silver atoms, usually formed through
the interaction of light, or high-energy ionizing radiation and its
secondaries, with the grains. During the process of development,
the latent image acts as a centre for further reduction of the silver
halide crystals. An emulsion fog or a spurious latent image (latent
image not due to irradiation) may be formed during the process of
emulsion manufacture and coating, or during emulsion storage. In
the finished emulsion its formation usually is favoured under the
influence of physical pressure and by an interplay of high ambient
temperatures, high relative humidities, or high concentrations of
chemicals in the atmosphere.
* The pamphlets “ Photographic Dosimetry of X - and Gamma Rays” [3] and
“ Report of the International Commission on Radiological Units and Measure­
ments [ i c r u ] ” [4] contain further discussions of the photographic process.
For details, see also, for instance, the books “The Theory of the Photographic
Process” [5], „GrundriB der Photographie und ihrer Anwendungen besonders
in der Atomphysik“ [6], “ Radiation Hygiene Handbook” [7] and “ American
Standard Method for Evaluating Films for Monitoring X - and Gamma Rays
having Energies up to 2 Million Electron Volts” [8].
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Latent-image fading:
Regression of the latent image, i. e., disintegration of aggregates of
developable free silver. Fading characteristics of the photographic
latent image depend on the type of emulsion, the temperature,
humidity and chemical contamination of the atmosphere, as well
as on the type of radiation exposure [9]. The increase of latentimage fading under the influence of high relative humidity during
exposure and storage is particularly pronounced, the effect of high
relative humidity being interrelated with temperature effects in a
complicated manner [10, 11, 12]. At a given relative humidity and
temperature and for a given type of radiation, fading usually is
highest in fine-grain emulsions, such as are used for nuclear-track
Photographic processing:
A term usually embracing a number of separate concepts:
Developing — the process of chemically reducing to atomic silver
all the silver ions in irradiated grains bearing latent image, with
the result of a visible darkening of the emulsion;
Fixing — the process of removing the unreduced silver halide grains
and hardening the emulsion, thereby rendering the developed image
Washing — thorough removal of processing solutions from the film
emulsion before and after fixing;
Drying — desiccation of the film emulsion to equilibrium with the
ambient atmosphere, best accomplished in dust-free air at room
temperature or at least without excessive heat.
The use of an acid stop-bath that instantly interrupts the developing
action is preferable to washing in pure water after development.
After the final washing following fixation, the films may be dipped
into a wetting agent that insures uniform drying without the
formation of “water marks” .
For the best results, it is desirable to adhere as closely as possible
to the processing rules laid down by the manufacturer of the films
and processing reagents.
Reciprocity failure:
Failure of the photographic (radiographic) effect to be constant for
a given product of radiation intensity and exposure time, indepen­
dent of exposure rate and time separately. For a given film-type
and a given type of radiation, it occurs whenever the absorption of
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more than one photon (i. e., more than one interaction) is required
for the production of a developable silver aggregate (latent image).
At very low intensities of light, reciprocity failure occurs when the
rate at which silver ions are reduced through the interaction of
light photons with silver halide molecules is slower than that of
the recombination of free silver and halogen. At very high intensities,
reciprocity failure is due to regional saturation effects, occurring
when interactions take place in such rapid succession that the free
halogen atoms are not removed fast enough, and a high probability
exists for their recombination with the free silver.
For high-energy ionizing radiations, one interaction often suffices
for the formation of a developable latent image, provided develop­
ment is vigorous; in this case, the radiographic effect is independent
of radiation intensity. With visible light, there is always more than
one interaction required.
Optical transmission density:
The logarithm to the base ten of the film opacity, i. e., the ratio of
the light intensity measured without and with the film in the light
path. One usually discriminates between specular and diffuse density
[5]. What is measured with the photometers (“ densitometers” ) used
in personnel monitoring as a rule comes close to diffuse density..
Where the term optical density is applied to photographic papers
rather than to film, it signifies reflection density, which is defined
in an analogous way.
The optical density of the unexposed film stems from the density
of the base and the “fog” of the emulsion layer as such, i. e. from
free-silver aggregates not due to radiation exposure, arising from
spurious latent images (see under “ latent image” ), or produced
during development. Development fog varies with the type of
developer; it increases with developing time.
The difference between the optical density of an exposed film (or
paper) and that of an unexposed film (or paper) of the same type
and batch, processed simultaneously with the exposed film, is re­
ferred to as net optical density.
Characteristic (or Hurter and Driffield) curve:
A plot of the optical density (usually net) as a function of the
logarithm to the base ten of the exposure (see Fig. 9, p. 52). Except
for small variations which may occur from emulsion batch to emul­
sion batch, this plot has a characteristic shape for each type of
film at constant conditions of exposure and processing. In some
instances, a plot of density vs. exposure on a linear scale or on a
log-log scale may be more useful, particularly in the absence of
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reciprocity failure; in this case, the plot results in a straight line
for low densities. In the absence of reciprocity failure the shape of
the characteristic curve of a film is essentially the same for exposures
to different types of radiation; the curves may be shifted, however,
parallel to each other, along the exposure axis.
Photographic sensitivity:
A quantity inversely proportional to the exposure required for a
given net optical density. One may define it simply as equal to the
ratio of a particular net density to the exposure required to produce
this density. According to the units in which exposure is measured,
one often distinguishes between dose sensitivity and flux sensitivity.
In this Manual, the term “ sensitivity” will signify dose sensi­
tivity. For a given type and batch of photographic film and for given
conditions of processing, photographic sensitivity varies with the
type and energy of the incident radiation.
2.8.1 Energy-dependence of photographic sensitivity for charged particles
In the energy region of interest in personnel monitoring, charged particles
transfer their energy to the silver halide grains mainly through collisions
with atomic electrons along their paths. As a consequence, the photo­
graphic sensitivity for charged particles increases with the path-length
of the particle in the emulsion, and, up to the point where one single
interaction between the incident particle and the silver halide grain is
sufficient to make this grain developable, also with the energy loss per
interaction. Any further increase in the energy loss within a particular
grain causes an increasing amount of particle energy to be wasted on the
already developable grains, which results in a decrease of the photo­
graphic sensitivity.
Because of its dependence on the path-length of the particle in the
emulsion, photographic sensitivity also varies with the direction of par­
ticle incidence and with the type of particle. For instance, for protons
whose ranges for a given particle energy are smaller than those of
electrons by three orders of magnitude, the sensitivity is much smaller
than that for electrons.
In general, the sensitivity of photographic emulsions to monoenergetic
electrons of perpendicular incidence increases sharply with electron
energy until the depth of penetration of the electron within the emulsion
is comparable to the emulsion thickness. This is the case at around
0.1 MeV for single-layer emulsions and at around 0.3 M eV for double­
layer emulsions [14]. As the energy of the electrons is further increased
and, correspondingly, the electrons lose less and less energy in the
emulsion proper, the sensitivity gradually decreases. In practice, the
resulting energy-dependence of the electron (or beta-ray) sensitivity is
smaller than would be expected, mainly because of the essentially diffuse
incidence of the particles on the emulsion, and the resulting diminished
dependence of electron path-length in the emulsion on electron energy
[14, 15, 16]. Furthermore, in the electron energy range for which the
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average energy loss per interaction is close to its minimum and thus does
not vary strongly with energy, sensitivity is expected to change only
slowly with electron energy, regardless of whether the energy loss per
grain is sufficient for grain developability. (For electrons in photographic
emulsions, the minimum energy loss per unit path-length occurs in the
neighbourhood of 1 MeV, while it lies in the GeV range for heavy
Also, in the case of beta-ray sources, the filtration in the path of the
beta-rays has no great influence on photographic sensitivity, since the
energy spectrum of the beta-rays from a given beta-ray source varies only
very slowly with absorber thickness [14,16].
2.8.2 Energy-dependence of photographic sensitivity for photons and un­
charged particles
Photons, neutrons, and other uncharged particles lose their energy to
the emulsion largely through the ionization produced by their charged
secondaries, released either in the emulsion proper or in its immediate
vicinity. Because of the complicated variation of the photon absorptioncoefficient with photon energy,. showing the well-known photoelectric
absorption edges (at 25.5 keV for silver and at 13.5 keV. for bromine)
and, as a consequence, large absorption maxima, the energy-dependence
of the photon sensitivity of photographic film is quite high, particularly
in the energy region in which photoelectric absorption prevails, i. e.,
below 100 keV. (In fact, the sensitivity of most photographic emulsions
is 20 to 40 times higher to photons of an energy in the vicinity of 40 keV
than to photons of an energy around 1 MeV. See Fig. 20, p. 67.)
The neutron sensitivity of a photographic emulsion can be deduced
roughly from the sensitivity of the charged particles produced by the
interaction of the neutrons with the photographic emulsion [17].
For high-energy photons or neutrons, for which the range of the charged
secondary particles produced by the incident radiation is larger than
the emulsion thickness, a sensitivity loss is recorded, unless the film
is exposed under conditions of charged-particle equilibrium, i. e., covered
with a sufficiently thick layer of emulsion-equivalent material to insure
that — on the average — for every charged particle leaving an infinitesi­
mal volume surrounding any one point within the emulsion, a particle of
practically the same energy enters the volume.
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C h a pter 3
It ist usually difficult to measure a quantity that is representative
of the effect of ionizing radiation on living human tissue. Therefore,
in the case of X- or gamma-rays up to around 3 MeV, measurements
are usually carried out in terms of exposure dose in roentgen. In
the case of corpuscular radiations, it is often practical to measure
incident-particle or energy flux. From these measured quantities it
is at least theoretically possible to calculate the absorbed dose
with the aid of the proper conversion factors, and to determine
the “ r b e dose” of ionizing radiation in living human tissue. (The r b e
dose (in rem) is equal to the absorbed dose (in rad) in the particular
tissue under consideration, weighted by the relative biological
effectiveness of the particular radiation in that tissue [4].)
The importance of a particular tissue is to a large extent determined
by biological considerations, but it also depends on the spatial dose
distribution produced by the type or types of incident radiation [22].
This distribution is both a function of exposure geometry and of the
penetrating power and the biological effectiveness of the particular
radiation; it is an important factor in the choice of a suitable
position for the dosimeter on the human body. In personnel moni­
toring it may be a good practice to have the individual carry dosi­
meters on the parts of the body on which the dosimeter readings are
habitually high [23]. However, if the high readings occur on the
extremities of a person working around penetrating radiation, it is
advisable to have the person carry one badge on the trunk and a
supplementary badge on the extremities.
If the photographic film (or film badge) is to be used as a personnel
dosimeter, a quantitative relation has to be established between the
* For details on dosimetry concepts in general see “Radiation Dosimetry”
edited by Hine and Brownell [18], ICRU Report (1959) [4], NCRP Report
(1957) [19], NCRP Report (1960) [20] and „Dosimetrie und Strahlenschutz“
by Jaeger [21].
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photographic effect and the radiation exposure. For this purpose,
the film (or film badge) has to be calibrated.
Although photographic film is one of the oldest indicators of ionizing
radiation, it is not ideally suited for quantitative measurements of
personnel exposure. There is a considerable difference in the chemical
composition of film and living tissue, causing the film response to
radiation to be different from that of tissue, both in absolute magni­
tude and in its dependence on radiation energy. Also, the relation be­
tween exposure to a given type of radiation and photographic density
is not always linear (although, in the absence of reciprocity failure,
such linearity exists, at least for low values of photographic
Only for radiation energies for which the film thickness is small
compared to the mean-free-path of the (primary or secondary)
corpuscular radiation mainly responsible for the photographic effect
is it possible to simulate tissue conditions, and thus approximate
tissue response. In the case of high-energy photons or neutrons
this may be accomplished by surrounding the films with tissueequivalent material in which corpuscular equilibrium is established
(for definition see section 2.8.2). In personnel dosimetry, this method
is not generally applicable, since one single film (or at least one
single film badge) is usually used to monitor a number of different
types of radiation, some of which (for instance electrons up to
1 MeV) would be completely absorbed in a tissue-equivalent layer
of thickness sufficient to establish electronic equilibrium for 1-MeV
X - or gamma-radiation. In fact, even the opaque paper layers of the
film packets absorb certain types of corpuscular ionizing radiation
contributing to the dose to superficial human tissue not covered by
clothing, and thus prevent these types of radiation from being
In the case of fast-neutron monitoring with nuclear-traek emulsions,
one often establishes proton equilibrium in a tissue-equivalent ma­
terial surrounding the emulsion. In this way, one decreases the
energy-dependence of the neutron response and also enhances the
absolute magnitude of this response. Nevertheless, the fast-neutron
response is so low that — in the exposure range of interest in per­
sonnel monitoring — dose interpretation necessitates counting of
individual particle tracks rather than measuring an over-all density."'
Because of the difference in film response to different types and
energies of radiation, the calibration of photographic film for use in
dosimetry would, in theory, necessitate the determination of charac­
teristic curves for all types of radiation to be monitored, and for a
sufficiently large number of different energies of each of the radiation
=:' One great advantage of this rather cumbersome procedure is its selectivity,
a feature that is of particular importance because fast-neutron fields are, as
a rule, associated with gamma- and beta-ray fields. Through track-counting,
one is in a position to separate the effect of neutrons from that of gammaand beta-radiation.
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types. Such a procedure would yield the photographic sensitivity
as a function of radiation energy for each type of radiation.
In practice, not all the phases of this procedure need be carried out
routinely. First of all, when the reciprocity law holds, the character­
istic curves obtained with different types of radiation and different
radiation energies have practically the same shape. Thus, it is not
necessary to repeat the density-us.-exposure curves in detail for all
types and energies of the radiations, but it suffices to obtain enough
points to locate the characteristic curves with respect to the logexposure axis. Also, in some instances, one is in a position to carry
out the calibration with radiation of the same type and energy as
the one to be monitored.
As a rule, the radiation fields to be monitored consist of mixtures of
various types of radiation of different energies; occasionally they
are entirely unknown. Therefore, devices have to be incorporated
into the holder of the film packet, to enable one to obtain at least
a rough indication of the type and energy range of the radiations
involved in a potential personnel exposure and (or) to reduce the
dependence of the film response on the types and energies of the
radiations to within certain acceptable bounds.
The film holder is usually a sturdily constructed case provided
with a pin, a clamp, or another device for fastening it to the clothing,
wrist, or fingers of the individual to be monitored. It should be easy
to load and unload, but, at the same time, should be fairly tamper­
3.3.1 X- and gamma-radiation
Most film holders in use at present contain metallic filters, covering
a portion of the inserted film packets [24,25,26]. The filters are
either of different atomic numbers or of the same atomic number
but of different thicknesses, and are often positioned symmetrically
in the front and back of the holders. In the energy region in which
these filters absorb an appreciable amount of radiation — which is
also the region of greatest energy-dependence of the film response —
they cause a differentiated density pattern to be reproduced on
the film. In the range in which photographic density is a linear
function of exposure, the density ratios behind the different filters
give an indication of the energy of the incident radiation and thus
facilitate the choice of a suitable calibration curve from which the
exposure may be determined.
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For many types of radiation, the layers of paper intervening between
the metals and the film are not thick enough to prevent the second­
ary electrons produced in the metals from reaching the film. In
this case, additional density differentiation may be achieved even
where there is relatively little difference between the absorption
of the radiation in the individual metals, particularly if the metals
in the back and front of the holders are arranged asymmetric­
ally [27].
The number of filters in the holders in use in different laboratories
varies. If only one filter is used, its choice is of rather great im­
portance, since it must reduce the energy-dependence of the selected
films to within the desired limits of monitoring accuracy, and thus
eliminate the need for a detailed discrimination between radiation
energies [28,29,30]. On the other hand, although theoretically
providing good discrimination between different types of radiation
of different energies, a very large number of filters may become
cumbersome in actual use, since intricate density patterns are
confusing, particularly to the inexperienced. Also, because of the
necessarily small filter-areas in the case of a large number of filters,
the film areas from which information is to be obtained often become
prohibitively small. This is the case particularly because scattering
of the radiation from the filter edges and undercutting in the case
of oblique radiation incidence may make it impossible to utilize
the marginal regions of any one area.
The lower limit of usefulness of the systems so far described lies
at a few mr of total exposure to X- or gamma-radiation of an
energy smaller than about 0.2 MeV. For energies above 0.2 MeV,
the lower limit lies at around 20 mr. A method employing scintillator
screens in contact with the film emulsions may extend the useful
range of the film badge down to 1 mr and less, even for photon
energies above 0.2 MeV. The method is based on compensating for
the ^decrease in the efficiency of the photographic process with
increasing photon energy by an increase in the efficiency of the
scintillating screen [31— 35]. This method is, however, not universally
applicable because of the reciprocity failure of the photographic
effect caused by the visible or near-visible light from the scintillator.
As a consequence, specially prepared emulsions, designed mainly
to minimize reciprocity failure, and special processing techniques
are often employed. Even then it is difficult to make the method
useful over an unlimited range of exposure rates.
Recently, one group incorporated the scintillating material into the
emulsion proper [36]. Experiments are under way to combine the
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scintillator and absorber methods, in an effort to produce a very
sensitive film badge whose response is to be practically independent
both of exposure-dose rate and of radiation energy [36]. At present,
such a film badge is not in routine use.
3.3.2 Beta-radiation, monoenergetic electrons
The light-tight wrapping surrounding commercial films has a thick­
ness of roughly between 2 and 25 mg/cm2 on the front surface of
the packet. A thickness of 25 mg/cm2 stops all electrons up to an
energy of close to 150 keV [37]. Thus, a film badge does not indicate
the presence of these electrons. Also, close to one-half of the betaradiation of maximum energy of around 0.7 MeV (and, of course,
considerably more of the beta-radiation of lower maximum energy)
is absorbed in the wrapping, and thus does not produce a photo­
graphic image. Higher-energy electrons (or beta-rays) are recorded
in the so-called “ open-window” area of the multi-filter X- and
gamma-ray badges (i. e., in the area in which the film packet remains
bare), or in the areas in which the cover consists of a thin, lowatomic-number plastic only.
In practical beta-ray monitoring procedures, the exposure geometry
is usually unknown and quite variable; the type of radiation, how­
ever, (beta-ray-emitting isotopes, electrons from accelerators, etc.)
is usually known. Since the beta-ray spectrum, after the filtration
of the softest components by the paper of the film packet, varies
only slowly with the source-to-film distance, i. e., with the thickness
of the layer of intervening air, a fairly good calibration may be
achieved with a standard source of the same isotopes as the ones
whose beta-radiation is to be monitored; this is the case particularly
if the radiation is diffusely incident.
Where the electron or beta-ray energy is entirely unknown, differ­
ential filter methods similar to those employed for X- or gammaradiation may be used; however, the filters here should consist of
thin plastic foils rather than metals. Fortunately, the sensitivity of
a number of films used for the monitoring of X- and gammaradiation does not depend appreciably on particle energy, at least
in the beta-ray energy range of the most common beta-ray-emitting
isotopes whose radiation penetrates the film wrapper.
3.3.3 Mixtures of X- or gamma-rays and beta-rays
A considerably more serious complication in beta-ray and electron
monitoring stems from the fact that beta-ray fields hardly ever occur
isolated. Even when one deals with pure beta-ray emitters, one has
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to consider the possible production of bremsstrahlung by the betaradiation. For any given source-strength, bremsstrahlung-intensity
increases sharply with the beta-ray energy, as well as with the
atomic number and the mass of the matter in the immediate vicinity
of the source and the mass of the source proper.*
Although the r b e of electrons and that of X- and gamma-rays are
assumed to be equal, a differentiation between mixtures of these
radiations is important from the biological point of view because of
the difference in their penetration to vital organs. Therefore, a semiquantitative differentiation is often attempted by means of readings
in the open-window area (i. e., in the area in which the film packets
remain bare) and in the film areas under the various thin aluminium
and plastic filters. Yet, many experts feel that the information to be
gained from film badges about beta-ray exposure in mixed radiation
fields is, at best, qualitative.
3:3.4 Neutrons
The photographic effect used in the personnel dosimetry of fast
neutrons is the formation of proton recoil tracks by elastic
scattering of neutrons on the hydrogen in the emulsion and its imme­
diate vicinity. It would be possible to determine the incident neutron
flux from the n-p scattering cross-section and the number of proton
tracks per cm2 having a given length and direction. However, since
the time and effort involved in a microscopic track analysis would
be prohibitive for routine dosimetry, one simply counts the number
of tracks. In a representative modern nuclear-track emulsion, a track
of minimum length (i. e., consisting of three grains) is formed by
neutrons of energy equal to or greater than 0.25 MeV [38]. Above
this threshold energy, the requirement of neutron monitoring in­
dependent of energy can be met if the variation in the number of
proton tracks can be made proportional to neutron tissue dose for
all neutron energies. Since, in respect to proton-track formation (i. e.,
in respect to its hydrogen content), the composition of the nucleartrack emulsion, plus film base and surrounding paper layers, is quite
similar to that of living tissue, it is not difficult to meet this require­
ment. In fact, it has been found [38] that, by establishing proton
equilibrium in a laminate of paper and aluminium foil, the variation
of the number of proton tracks per unit film area as a function of
fast-neutron energy may be made to parallel that of the first-collision
dose [20].
* For small sources in air, low-atomic-number plastic, or soft tissue, the
amount of bremsstrahlung contributing to the external dose is negligible.
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Since thermal neutrons, through the N14 (nth, p) C14 reaction, also
cause proton tracks in a nuclear emulsion, the mere presence of
proton tracks is not in itself indicative of the presence of fast neu­
trons. Therefore, in mixed radiation fields, further methods of
differentiation are required.
3.3.5 Neutrons in mixed radiation fields
Because of their mode of production and their high reactivity,
neutrons usually occur in highly mixed fields of radiation. However,
since the relative photographic effectiveness of X-, gamma-, and
beta-radiation on the one hand, and of the thermal and fast neutrons
on the other, is not proportional to their relative biological effective­
ness, determining the film response to the sum total of these radia­
tions is not sufficient for personnel monitoring.
The customary film holder used for the monitoring of mixed radia­
tion fields consists of at least two metal filters of equal mass, one of
cadmium and the other of tin. As a rule, both the nuclear-track film
packet and the conventional gamma-ray-monitoring film packet are
placed in this holder. As the (nth, 7) cross-section of tin is quite small
compared with that of cadmium, the density of the conventional film
behind the cadmium filter is considerably higher than that behind
the tin filter when thermal neutrons are present. On the other hand,
in the nuclear emulsion, the number of proton tracks behind cad­
mium is smaller than that behind tin in the presence of thermal
neutrons, because the cadmium filter shields the film from the
thermal neutrons. In the absence of thermal neutrons from the
radiation field to be monitored, the areas behind cadmium and tin
appear alike, both on the nuclear-track film and on the conventional
monitoring film. The density obtained on the conventional X- and
gamma-ray-monitoring film, both by thermal neutrons in the areas
not covered by metal foils of high capture cross-section and by fast
neutrons, is usually negligible [39].
It may also be pointed out in this connection that, for high-energy
X- or gamma-rays, even in the absence of thermal neutrons, the
areas behind metallic filters will be darker than the open-window
area since the action of these radiations upon the film is intensified
by the electronic build-up in the metal foils. Furthermore, equal
densities behind the filters and the open window can be achieved
by exposure to a number of different combinations of radiations,
even in the absence of thermal neutrons.
Another method of discriminating between gamma-radiation and
thermal neutrons involves the use of a boron-loaded silver-activated
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zinc sulphide screen over a portion of the film surface [40]. The alpha
particles produced during the capture process cause scintillations in
the zinc sulphite, which, in turn, are recorded by the photographic
film. The thermal-neutron dose is determined from the differences
in film density behind the single metallic filter, the screen and the
open-window area. Here again, the accuracy attainable is limited by
reciprocity failure.
The monitoring emulsions are selected for their uniformity and
reproducibility and for their ability to cover a desired exposure range,
with good precision. For X- and gamma-ray monitoring, double­
coated commercial X-ray film, or film singly or doubly coated with
special monitoring emulsions, is used in most laboratories; at least
one of the larger laboratories employs special emulsions coated on a
paper base.
It usually takes two emulsions to cover the full monitoring range.
For the daily routine monitoring, a range from 20 mrem to about
5 or 10 rem would be quite satisfactory; but as a rule, for the sake
of full coverage in the case of an accident, an emulsion for the range
from 10 to 500 rem is included as well. Some laboratories work with
a special film, which is coated on one side with a sensitive emulsion
and on the other with an insensitive one. For ordinary use, the
exposure is determined from the net density of the complete
developed film. Only when the film is too dark for evaluation, which
may be the case under some conditions involving a radiation ac­
cident, is the sensitive emulsion removed after processing, the
evaluation proceeding from the density of the insensitive emulsion
alone. For the monitoring of fast neutrons, commercial nuclear-track
films are usually employed.
Most commercial film material from reputable manufacturers is coated
uniformly enough, at least on any one given batch of films, to pro­
vide for the uniformity of photographic characteristics required for
personnel monitoring. For a high precision in exposure interpretation,
it is further required that, at the density being measured, the densityvs.-exposure curve have a steep slope, i. e., that a large density
increment correspond to a small exposure increment, for film pro­
cessed according to prescribed methods. Also, for convenience in
handling, particularly during processing, a stiff film (or paper) base
is of considerable advantage.
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The film packets, as well as the individual films inside, are usually
marked for identification. The simplest way of marking film is by
hand, with a pencil or stylus.
As a rule, numbers and (or) letters are used to identify the wearer
and often also his institution and the monitoring period. A badge
identification number is often perforated into the material of the
metallic holder. It is then possible to transfer this number onto the
film by exposing the film-loaded holder to low-energy X-radiation,
shielding all but the perforated area from the radiation. Another
method consists of printing numbers on both the paper of the packet
and the individual films with the blunt dies of specially designed
stamping machines. The dies may or may. not be inked; they make
their imprint on the films through the exerted pressure, without
perforating the packets. Binary coding may be used to conserve
space on the film surface. The printing methods are fast and con­
venient and lend themselves well to automation.
In institutions in which the film holder is used as an identification
plaque (“badge”) for the wearer, it may carry also the wearer’s
photograph and further identifying symbols.
Where film is not stored as part of a permanent record, an identify­
ing portion of the film holder may remain with the film throughout
all stages between exposure and evaluation, thus making film mark­
ing unnecessary [30, 40].
3.6.1 Humidity-proofing
All calibration would be in vain if, between exposure and processing,
the latent image produced in the monitoring samples were allowed
to undergo changes considerably different from those in the calibra­
tion samples. The ideal arrangement would be to accumulate the
calibration exposures over the entire period during which the
monitoring badges are being carried and shipped, and under the
same conditions of ambient temperature and humidity. This, of
course, is not possible in routine personnel monitoring.
In colder parts of the temperate climatic zones, most monitoring
films in present use exhibit only relatively little latent-image fading
unless exposed directly to the heat of the sun or a stove, or exposed
to light, water vapour or other chemical vapours, etc. Two films of
the same emulsion batch, identically exposed tand stored, probably
will not show a difference in density of more than 10 or 15°/o if
the one is developed immediately after exposure, while development
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is delayed on the other one for a week or two. The resulting error in
exposure interpretation would be well within the limits of the over­
all accuracy to be expected in photographic personnel monitoring.
However, in tropical or sub-tropical climates, and in parts of the
temperate zone having hot, humid summers, the latent image may
fade so strongly, or there may be so much fogging of the film, that
an exposure interpretation may become impossible. In such climates
it is necessary to use film packets enclosed by the manufacturer in
humidity-proof plastic bags and to remove the films from these bags
only immediately before processing, and in an air-conditioned room.
3.6.2 Precautions in storage and shipping
When not in use, both the calibration films and the monitoring films
are stored at temperatures preferably between 5 and 15 °C, and at
relative humidities of around 40% . Thus, while ordinary refrigera­
tors are quite satisfactory for film that is packed in humidity-proof
bags, they are to be used with caution for unprotected film. Also,
care has to be taken that the films are brought to room temperature
before they are distributed for use or exposed for calibration, and
that they are brought to a temperature close to the processing
temperature before processing. Great temperature differentials
during the warming-up stage are to be avoided, since they cause
detrimental water condensation on the film surfaces.
Special precautions are required to keep the monitoring and calibra­
tion films not in use away from ionizing radiation. Where it is not
possible to plan for storage and processing facilities remote from
radiation sources, lead or concrete protective barriers are used. Also,
packages containing film should bear special shipping labels that
identify the package contents and warn against the dangers of ex­
posure to ionizing radiation.
Furthermore, unexposed control films should accompany each film
shipment* from the central monitoring station to the various
monitored installations. During the monitoring period, these control
films remain at the institutions, but are protected from radiation. It
is a good practice to keep them on the same rack on which the
monitoring films are stored when not in use. They are then returned
along with the rest of the films, and processed together with them.
The density of the control films is an indication of possible accidental
exposure during transport or storage. Control films also should be
kept at the storage facility of the central monitoring station.
* Used in the broader American sense throughout this Manual, i. e. consign­
ments, irrespective of the mode of transport.
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Unless the climate is very moderate and uniform throughout the
year, all film manipulations are best carried out in an air-conditioned
room or building. Processing instructions supplied with the films
should be followed as closely as possible. One should avoid, in
particular, developers having a tendency to produce reversal effects
at high densities. This reduces the chances of ambiguity in the rare
instances of accidental high exposure, and also eliminates difficulties
due to reciprocity failure. As a rule, a commercial X-ray developer
is satisfactory.
In order to be independent of variations in the strength and tempera­
ture of the developer used, and of small variations in processing time,
all monitoring films are usually developed along with their calibra­
tion films. Although, for the reasons discussed above, it is then still
necessary to follow the instructions of the manufacturer regarding
developing time and temperature, the permissible variations in these
factors are relatively large, and costly precise stabilization of the
developing temperature becomes unnecessary; nevertheless, a certain
amount of temperature control of the processing solutions is usually
For the simultaneous processing of large numbers of films, one
requires special racks which hold the individual film samples
securely and do not impede continuous access to fresh processing
solution. An alternative processing method, which is used by only
one personnel-monitoring station at present, is to assemble a long
strip simulating cinematographic film. The individual film samples
are fastened along two opposing edges to long strips of cellulose
tape, fed from two reels. A little machine, specially designed for this
purpose, accomplishes this task readily. Simultaneously, the film strip
is rolled on drums; it may be developed like ordinary 35-mm film.*
Whatever the processing method, care has to be taken to achieve
uniform developmerft. Constant agitation is the only means of
insuring that fresh developing solution is brought into contact with
the entire surface of each film at all times. However, when large
developing racks containing several hundreds of films are used, a
periodic mechanical agitation of the racks proper often results in
The station using this method reports that the development achieved in this
way is uniform. Nevertheless, it is recommended that a laboratory wishing
to adopt this method first run its own processing checks in the particular
film-tank or drum it plans to use.
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eddy currents and, consequently, in streaking of the film material
[3]. The best type of agitation keeps the solution in motion rather
than the racks. It may be achieved by bubbling a slow stream of
nitrogen through the solution [41, 42]. However, fairly good results
(uniformity in density to within about 4°/o) may also be achieved
with suitable developing racks without any agitation, if the develop­
ing solutions are stirred thoroughly immediately before the loaded
racks are immersed [3].
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C h a pter 4
As a rule, a group just starting a personnel-monitoring service should
be in possession of just the bare minimum of basic equipment re­
quired for satisfactory operation. This insures the possibility of a
gradual expansion as the needs of the particular group become
apparent; with the experience of a few months (or years) of opera­
tion, adaptations may be made that, eventually, will bring about a
service better suited to the individual needs of the group than could
have been established by copying all the details of a service else­
where. Nevertheless, access will have to be obtained from the start to
a certain amount of equipment common to most monitoring stations.
Also, adequate space will have to be provided to insure safe and
smooth operation and, if possible, to take into account future ex­
This section deals only with the main features of the basic layout
and equipment required for a photographic monitoring service, but
no actual specifications or sources of supply are given. The i a e a
has available a selected list of laboratories in different countries,
willing and able to advise institutions interested in starting such a
service and to suggest suitable equipment specifications. The i a e a
also is in a position to suggest suppliers of commercial equipment.
In some instances, it will be possible to make use of equipment such
as X-ray machines, radioisotopes or darkrooms, usually available in
the radiological departments of hospitals. The space and equipment
requirements given in this section may then be reduced.
According to the different procedural requirements, the personnelmonitoring plant consists of several distinct areas: the generaloverations area (or areas), providing space for film storage, badge
loading, film marking (if done by pressure), densitometry, exposure
evaluation and records; the calibration area, containing the sources
and accessories required for an adequate film calibration with the
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types of radiation present in the radiation fields to be monitored, as
well as a film-marking source, if films are to be identified radiographically; and the film-processing area. While the personnelmonitoring plant forms an organic unit, care should be taken to
isolate the calibration area either through distance or through
structural shielding (or both) from the other areas, so as to prevent
the other areas from having, at any time, a radiation level higher
than natural background.
In tropical or sub-tropical climates, and in the portions of the
temperate zone having hot and humid summers, air-conditioning
should be provided at least in certain portions of the area of opera­
tion. This will prevent damage to valuable equipment due to fungus
infestation, insulator leakage, etc., as well as damage due to changes
in the latent image during operational procedures.
4.2.1 Ceneral-operations area
Films and film holders
Some of the major suppliers of monitoring film have widely
distributed regional branch offices. The selection of film, in addi­
tion to being influenced by the technical considerations discussed in
chapter 3, will also depend on the nearest reputable commercial supply
office from which film shipments can be expected to arrive regularly
and within a reasonable length of time. Preferably, all films obtained
for use in any one monitoring period should be from the same
emulsion batch, as considerable batch-to-batch variations in film
sensitivity and even in -energy-dependence may exist, making it
necessary to prepare a set of calibration exposures for each batch.
Attention should also be paid to the expiration date appearing on
the film box, which indicates the end of the period for which the
film company recommends the use of a particular batch of film.
The film holder (“badge” ) should not be chosen independently from
the films. It may be best to rely first on a combination that has
proven satisfactory in a well-established laboratory of a Member
State. If this is done, it may be possible either to obtain the holders
commercially, or at least to obtain a pattern after which holders may
be manufactured in a local shop. In either case, care should be taken
that the various metallic foils incorporated into the holders are all
of the same chemical composition from holder to holder and that
possible variations in their thickness do not cause any appreciable
error in the interpretation of low-energy X- and gamma-ray exposure.
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A good refrigerator will be required for film storage. Preferably, it
should be adjusted to operate above 0°C. If the relative humidity
in the refrigerator is above 40 or 50°/o, open boxes of packets that
were not individually moisture-proofed may have to be placed in
moisture-proof bags. Unopened boxes of film, as delivered from the
film distributor, can be stored without any danger in a refrigerator
operating at a higher relative humidity, even if the individual film
packets are not enclosed in moisture-proof bags.
Percussion press
If pressure marking is the method of choice for film identification,
a percussion press either has to be obtained commercially or has to
be built. Logically, the percussion press is located in the vicinity of
the loading area*.
While in many instances the experienced eye can judge very low
densities with considerable accuracy, a photometer, capable of
measuring the change in film opacity with exposure, is indispensable.
Most photometers in use in radiation-monitoring laboratories are
photoelectric precision instruments, incorporating a stable light
source, a photocell or photomultiplier, and a current measuring
device. They may T)e used as relative indicators of opacity changes,
or calibrated in terms of optical density (therefore the term “densito­
meter” ) by means of a standard density wedge; such a wedge may be
supplied with the instrument, but also can be obtained from one of
the larger manufacturers of photographic films.
For routine use, a photometer with a sensitivity sufficient to indicate
a decrease in original light intensity by a factor of between 102 and
JO3 (corresponding to an optical density between 2.0 and 3.0) should
be quite satisfactory. However, since the photographic method of
personnel monitoring is also counted upon to give information in the
important cases of accidental high exposure, a photometer indicating
a light-intensity decrease of 105 or 10® (corresponding to optical
densities 5.0 or 6.0) could prove a worth-while investment.
Where large voltage-fluctuations are expected in the incoming
powerline, it may be necessary to operate the densitometer with a
* For radiographic marking see section 4.2.2.
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For nuclear-track counting a good microscope with a mechanical
stage is required. It should be equipped with an eyepiece with scale,
and a special small-depth-of-focus objective, allowing a magnification
of the order of 1000 times with oil immersion.
Record storage
In order to make full use of the possibilities of the photographic
method for providing a direct documentation of individual exposure,
many authorities feel that all developed films should be stored in
such a way as to permit future re-checks of readings in the case of
medico-legal difficulties. Inasmuch as storing the personnel-monitoring films without their calibration films would be useless, it is
necessary to provide such storage facilities for all developed films
at the location at which the calibration films are available, i. e. in
the monitoring centres. No general recommendations can be made
about the film-storage period. A compromise between the desires
of the monitoring service, the user, and the official authorities will
have to be found in each individual instance.
The policy on how and where written records are kept of the per­
sonnel exposure depends to a considerable extent on whether a
particular film-badge service is part of a governmental organization
interested mainly in monitoring for the compliance with safety regu­
lations, or a private organization, responsible both to the govern­
ment and the customers. At any rate, the film-badge service should
provide — preferably in duplicate — a clear statement of each
individual’s exposure during each monitoring period, for each type
of radiation. The exposure should be expressed in absolute units
that can be related readily to the maximum permissible exposure
of a particular type and energy of radiation.
In order to facilitate the exposure interpretation from film density
the film-badge users should supply a record of the type or types
of radiation employed, and of the part of the body on which the
badges are carried*. It is further desirable that the monitoring
station prepare cumulative records (quarterly, annual, etc.) of per­
sonnel exposure, giving the training, occupation, age, sex, etc., of
the individuals [43, 44].
* Often, personal communication between monitoring station and user can
be of additional help in explaining film-density patterns that otherwise would
be difficult to interpret. This is one of the reasons why it is desirable for
a monitoring station not to service laboratories too remote for ready personal
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4.2.2 The calibration area
The complexity of the radiation fields to be monitored determines
the complexity of the calibration facilities. The following descrip­
tion covers the calibration sources required for personnel monitoring
around the more commonly encountered radiation fields.
X- and gamma-raijs from around 30 keV to 1 MeV and above
As a rule, the routine calibration consists in establishing a densityus.-exposure curve, if feasible for the radiation energy spectrum re­
sembling the one to be monitored, or otherwise for any other energy
spectrum that is readily obtainable. Furthermore, the energy-depen­
dence of the film sensitivity should be determined, if possible, once
for each emulsion batch. Ideally, this determination should be car­
ried out with monoenergetic sources covering the energy range of
interest. However, since standard monoenergetic gamma-ray sour­
ces of adequate strength are not available for the important lowenergy portion of the range, one customarily employs narrow energy
bands of X-radiation from commercial X-ray machines for the lowenergy portion, and gamma-ray sources only for the high-energy
portion of the range. One laboratory, which is particularly inter­
ested in two specific long wave-lengths, produces these wave-lengths
by the X-ray fluorescence method. An X-ray machine is required
for both methods. In the laboratories in which radiographic identifi­
cation of the films is the method of choice, this machine may be
used for the marking process as well*.
A reliable 250-kV X-ray generator having either pulsating or con­
stant potential will usually be satisfactory. Either an industrial or a
therapy-type X-ray tube may be used, the therapy tube being as a
rule preferable because its larger focal spot and target angle insure
a more uniform calibration beam. It should be possible to regulate
both the incoming line voltage and the filament current, and there
should be meters in both circuits. Where line-voltage variations
greater than a few volts are to be expected, a voltage-stabilizer
should be employed.
In order to isolate narrow calibration bands from the continuous
X-ray spectrum, it is necessary to employ relatively heavy filtration
in the X-ray beam. In selecting a suitable set of filters, one may be
guided by the consideration that a particular band of X-radiation is
Any low-energy X-ray beam (30-kV exciting potential, or preferably less)
can be used for marking. Some laboratories have a special set-up for X-ray
marking; at least one uses a grenz-ray unit.
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satisfactory if, in its absorption characteristics, it behaves similarly
to monoenergetic radiation.
Whether this is the case may be determined experimentally by
means of absorption curves in a metal, say, in aluminium or copper.
The X-ray band is satisfactory if the absorption curve produced by
adding absorber materials to the filtration required for the particu­
lar band is essentially exponential; i. e., if, by adding absorber
materials, the half-value layer of the emerging radiation does not
change appreciably.*
The filtration required for such a band may be obtained by a num­
ber of different metal combinations in different thicknesses, as well
T a b l e I a)
Filtration b)
(mr/min at 1 m
and 7.5 mA)
effective energy
1 040
?■! From reference [28],
' Exclusive o f inherent filtration, here equivalent to 0.08 mm Cu at 170 kV.
c) The figures in this colum n can be considered as representative only for the particular
X-ray tube used.
For experimental details on how to obtain absorption curves, half-value
layers, etc., see ICRU Report (1959) [4]. It is recommended that pure
metals be used in order to make a comparison with the work of other
laboratories possible, and so that “effective energies” can be determined
(see following paragraph in text).
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T able
II a)
Filtration b)
a) With the exception o f the filter used
in the literature [45], The 0.6-mm Cu
they prevent the K X-radiation from
“ effectivei energy” quoted here are
publication. The filters were adjusted
nam ely, around 20 mr/min at 1 m per
effective energy
half-value layer
(mm Cu)
at 50 kV, the filter selection was described in detail
filters at the two highest energies were added later;
the tin from reaching the detector. T he values o f
new er and probably better than the ones in the
to give similar outputs at all five calibration points,
mA o f filament current.
Exclusive o f inherent filtration, which was equivalent to about 4.5 mm A1 over the spectral
range covered in this Table.
as by single filter blocks. Tables I and II give examples of how one
may produce energy bands satisfactory for the calibration of film
badges as well as of other radiation detectors*. The columns headed
“ effective energy” ** give the energy of the monoenergetic radia­
tion having similar absorption characteristics to those of the selected
narrow bremsstrahlung band. If suitable metal-rolling facilities are
not available locally, the metal for these or similar filters may be
purchased in sheet form, already rolled to a thickness not too far
from the desired optimum.
If fluorescent radiation is to be used for calibration purposes rather
than the narrow bands isolated from the bremsstrahlung spectrum,
a special fluorescence chamber, to be attached to the X-ray machine,
has to be built [47,48], and suitable radiators and filters have to
be purchased. (See also section 5.5.1.)
For the actual film calibration, the film response to known exposure
doses at one suitable energy is measured in detail, and periodic
checks are made for other energies, in order to establish the batch* Further examples are available >in the literature [46].
** This is the customary English term; the term “energie equivalente”, used in
the French original of Table. I, is probably more descriptive. The concept
of “effective energy” or “energie equivalente” is meaningful only for very
narrow bremsstrahlung spectra.
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to-batch agreement of the energy-dependence of the film response"*.
For determining the exposure doses at the film position, one requires
a laboratory standard of exposure dose. Therefore, the photo­
graphic monitoring laboratory should own an ionization-chambertype instrument with a set of chambers useful for both high and
low energies, over a range from at least 1 to 20 r. The instrument
is best reserved exclusively for work by the monitoring laboratory,
as it may lose its calibration through rough handling. The instru­
ment should be calibrated with radiation of energies similar to the
ones for which it is actually to be used**. Its constancy should be
checked periodically with a small radioactive source. A check on
the voltage sensitivity of its electrometer is also desirable.
Calibration laboratories often work with constant potential rather
than with pulsating generators. For this reason, even if they use
the generator voltage and the beam filtration specified by the moni­
toring stations, their spectral bands differ somewhat from the ones
produced in the monitoring stations employing pulsating potential.
This is no serious shortcoming, since, for two beams having the
same half-value layer, the calibrations done with constant and with
pulsating potentials agree within the accuracies required of the
For the film calibration in the 1-MeV energy range, one may em­
ploy laboratory standards either of radium, of Co60 or of Cs137***. If
the activity of the source is not known exactly, the exposure-dose
rate may be determined with the high-energy ionization chamber
supplied with the laboratory standard of exposure dose.
Beta-radiation (electrons)
A beta-ray calibration is more readily carried out with a commer­
cially available thick plaque of natural uranium. While such a
uranium plaque cannot be considered a standard beta-ray source
(it emits gamma-rays, alpha-particles, and some bremsstrahlung, as
well), it represents a convenient film-calibration source that can be
used in contact with the film packet or badge. Its beta-gamma sur­
* For details on accepted calibration procedure, see ICRU Report (1959) [4].
** The IAEA is in a position to accept requests from Member States for the
calibration of laboratory standards. Such calibration might be done, for
instance, at laboratories suggested by the Bureau International de Poids et
Mesures (BIPM) and ICRU.
*** See Appendix I of ICRU Report (1959) [4] for photon energies and specific
gamma-ray emissions.
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face-dose rate behind a 7 mg2 absorber (in thickness approxi­
mately equal to the dead layer of the skin) has been determined
by several experiments [49,50]. It may be taken to be about
225 mrad/h.
In many instances, it may be possible to obtain on loan a standard
source of beta-rays whose energy spectrum is similar to the one
that is to be monitored. Such a source may be used to establish the
relation between the response of the particular film packets or
badges to the beta-rays to be monitored and to uranium; sub­
sequently, one may use the uranium calibration with the proper
correction factor.
A detailed discussion of the characteristics of neutron sources avail­
able for calibration purposes is given in Table 13.1 of icru Report
(1959) [4], At present, the most widely used portable fast-neutron
source is the Ra-Re (a, n) source, which yields about 1.5 X 10" n/sec
for each curie of radium*. Like all portable neutron sources, it
emits neutrons having a wide spectrum of energies. When used to
expose neutron film to higher neutron doses, its high gamma-ray
background interferes with proton-track counting. The Po-Be (a, n)
source, which yields about 3 X 106 n/sec for each curie of polonium,
has a smaller gamma-ray background, but its half-life is only around
four and a half months. There is, at present, a trend to switch to
Pu-Be (a, n) sources for calibration purposes. They are somewhat
bulkier, but their low gamma-ray contamination and the long
half-life of plutonium are definitive advantages. They yield about
1.5 X 106 n/sec for each curie of plutonium.
It may not always be necessary for a laboratory establishing a photo­
graphic neutron-monitoring service to install its own neutron source.
In many instances, there may be access to already available fastand thermal-neutron sources, in geometries suited for instrument
(and film-badge) calibration. However, these sources may have to
be calibrated first, or the existing calibration may have to be
checked** [20]. Furthermore, in the case of monitoring for thermal
* With the aid of this information, one can deduce by simple computation [19]
that it takes about 20 hours to produce an r b e dose of 5/50 rem — 0.10 rem
in a distance of 1 m from a Ra-Be source containing 1 c Ra (5 rem is the
maximum permissible annual r b e dose and 50 the number of work weeks per
** The IAEA, in cooperation with the BIPM and ICRU, is in a position to offer
advice and assistance regarding the calibration of neutron sources. See also
footnote p. 35.
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neutrons, a routine film calibration with thermal neutrons is usually
unnecessary. The radium, Co60, or Cs137 gamma-ray calibration
should suffice, once a relation between the thermal-neutron re­
sponse and the gamma-ray response of the badge is established for
the particular conditions of development.
4.2.3 The darkroom
Location and design
In its essentials, the radiation-monitoring darkroom differs only very
little from the darkroom of the radiographic department of a gene­
ral hospital. It should be remote or otherwise shielded from all
radiation sources and should be kept at a temperature close to that
of the processing solutions (20 °C). If possible, it should be readily
accessible from the evaluation, record and storage areas of the per­
sonnel-monitoring group.
Information on darkroom design including all details, from proper
light-locks, light-reflecting paints, darkroom illumination and venti­
lation to processing tanks and their temperature-controlled water
supplies, film-processing holders, film dryers and storage cabinets,
is available from commercial suppliers of darkroom equipment and
X-ray accessories. As a rule, the personnel-monitoring darkroom
need not be easily accessible to outsiders during the processing ses­
sion; therefore it is possible to dispense with costly and space-con­
suming darkroom mazes. A simple, well-designed double-door lightlock is entirely adequate. In some instances, one single, positively
light-tight door might suffice, for a start.
Film-processing holders
Personnel-monitoring films are usually processed in relatively elabor­
ate holders, enabling one to handle simultaneously several hundred
films of the size used for dental X-rays. Not all the holders in use in
the various existing laboratories are commercially available. Many
were assembled in laboratory shops, sometimes from smaller,
commercially available dental-film-processing holders.
Film-processing tanks
Large film-processing holders necessitate relatively large tank-type
processing vessels similar to those in use in radiographic darkrooms,
usually of a capacity of 20 liters or more. Because of the need for
temperature control, the individual solution tanks are, as a rule,
submerged in a large, sink-type water vat, whose steady water
supply is kept at the desired processing temperature. Since film
should be washed in steadily flowing water, this water vat, if made
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large enough, may also be used for film washing. While this arrange­
ment eliminates the need for a separate wash tank with flowing
water, it is not the most desirable arrangement, because it is difficult
to keep the water that circulated around the outside of the solution
tank clean enough to prevent smudge deposits on the film surfaces.
If a group decides to design and build its own processing tanks,
sinks, etc., it should consider the corrosive action of some of the
processing chemicals, which limits the materials and construction
methods acceptable for photographic processing equipment [51].
Temperature control
As pointed out earlier, no elaborate precision unit for temperaturestabilization is required, provided all films, including the calibration
films, are processed simultaneously. A stabilization to within ± 1 °C
should be adequate. Therefore, the thermostatic mixing valves
supplied commercially with radiographic darkroom equipment are
quite satisfactory. According to climatic conditions, flowing hot
water or flowing refrigerated water — or both — is required for
the proper operation of the valve in the desired temperature range.
Hot water is usually available in the laboratory. Suitable watercooling units are supplied commercially by the manufacturers of
darkroom equipment.
Processing chemicals
As pointed out in section 3.7, the commercial X-ray developer and
fixer recommended for use with the particular films are usually
employed with the conventional monitoring films, and most of the
time also with the nuclear-track films. Acid stop-baths and wetting
agents are also commercially available. In spite of the slightly
higher expense, the developing and fixing reagents are best pur­
chased as concentrated liquids rather than in powder form. The
reason is that the dust from the powders may easily contaminate
working surfaces during the quite laborious mixing procedure and
may cause spotting of the films, which could interfere with the
determination of photographic density. If agitation of the processing
chemicals through nitrogen bubbling is desired, details of the
method, going beyond those given in the next chapter, may be
obtained from the literature [41,42].
Film dryer
The mode of drying may slightly affect film density, but as long as
all films are dried simultaneously, this is immaterial for personnel
monitoring. Any method that guarantees a clean, evenly dried film
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surface should be satisfactory. Where speed is important, a com­
mercial dryer of the forced-air or desiccant type, or of a combination
of the two types, may be of advantage. Warm-air drying is satis­
factory for films having a relatively thick base. One laboratory found
that films whose base material is 0.2 mm thick could be successfully
dried in warm air, while films with a 0.14-mm base showed a ten­
dency to curl, a condition leading to film losses out of the developing
racks. Also, because of the possibility of dust impregnation of the
wet film surfaces, home-made forced-air systems -should not be used
without adequate air filters. Where time permits, drying in room
air is quite satisfactory.
It is rather difficult to lay down manpower requirements applying
to different types of photographic monitoring laboratory, regardless
of the number and types of radiations to be monitored, and regard­
less of the degree of automation and simplification of the various
procedures. However, in general, one physicist experienced in the
field of personnel monitoring should be able to handle a large
department with the aid of technical assistants having some previous
experience, supplemented by on-the-job training, and with the aid
of clerical help. In a laboratory of a given scope, the number of
persons required will depend largely on the organization and sim­
plification of such bottle-necks as film dispatching (packing, address­
ing, etc.) and the recording and reporting of results.
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C h a pter 5
The existing photographic personnel-monitoring services may be
classified from several points of view. Probably the most important
classification categories are the type of the monitoring laboratory
and the type of film badge used.
Types of monitoring laboratory:
(1) Medical, industrial, or research laboratories, using relatively
small amounts of radium, radioisotopes, and bremsstrahlung
sources, but no sources of neutrons; and
(2) Atomic reactor plants or other laboratories using relatively
strong sources of all types of ionizing radiation.
Types of film badge used:
(a) Single-filter badges with or without open window;
(b) Multi-filter badges with open window, either with all filters of
the same material, or with filters of different materials;
(c) Badges utilizing primarily the electron emission of metal foils
rather than their absorption; and
(d) Fluorescent-radiator badges.
The two sub-divisions of the first group may be combined with each
of the four sub-divisions of the second group; the result is eight
combinations. Examples will be given for the combination classes
that are in most general use at present, and, whenever possible,
references from which further details may be obtained. A particular
monitoring station may handle laboratories in both sub-divisions of
the first grouping and may use more than one type of badge
(i. e. may fall only into one or into two categories of the second
grouping). All monitoring stations whose services are described are
among those having expressed their willingness to give assistance
in establishing new services and to provide, upon request, at least
temporary personnel monitoring to installations in Member States.
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The description of the services is never complete. In fact, in certain
instances, only some noteworthy phases are covered, in which the
particular service differs from the majority of other services. In
general, the relatively simpler services, which are reviewed first,
are described in greater detail than the more elaborate ones. No
further mention is made of the additional routine personnel-monitor­
ing equipment in use, such as ionization-chamber-type pocket dosi­
meters, which, as a rule, are used to supplement the film-badge
service. Finger-ring badges, wrist-type badges, etc., are not des­
cribed separately, as they usually are adaptations of the routine
chest badge, modified for the specific use.
In general, it would not be wise for a laboratory planning to
establish a photographic personnel-monitoring service to copy any
one particular existing service completely. Nevertheless, the exam­
ples of existing services given in this section may prove useful as
guides for selecting one or the other suitable detail. The resulting
method may turn out to be an entirely new compromise, in which
existing procedures are adapted to the needs of a particular group.
CLASS 1-a [23,28,30]
5.1.1 First example
Film holder. Commercially available lidless lead box, 1 mm wall
thickness; a filter, consisting of 0.2 mm lead and 0.7 mm tin, and
again 0.2 mm lead, fits into the box.
Fig. 1
Example 5.1.1; film badge and its assembly
1 — Paper cover with identification number; 2 — Plastic tubing;
3 — Lead box (1m m lead); 4 — Kodirex film packet; 5 — 0.2m m Pb
+ 0.7 mm Sn + 0.2 mm Pb; 6 — Kodak type M film packet.
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Films. Types M and Kodirex, made by Kodak*, regular dental-size
packets (about 3 X 4 cm).
Film-badge assembly. (See also Fig. 1.) The sensitive Kodirex film
is placed at the bottom of the lead box and the filter assembly on
top of it; the insensitive type-M film lies on top of the filter.
Badge identification. Both the holder and the films are numbered,
the films with the aid of a punching press.
Calibration. The film response is determined as a function of photon
energy; filtered bremsstrahlung is used as well as Co60 gammaradiation. A full characteristic curve is obtained with X-rays pro­
duced at 60 kV constant exciting potential. During irradiation, the
badge is backed up with a sheet of plastic, simulating the human
body, and is rotated about an axis perpendicular to the direction of
the incident radiation, so that the angle of incidence of the radiation
on the film surface varies between 0 and 180 degrees. This decreases
the error due to the rather high direction-dependence of the response
of film exposed in this particular holder.
Processing. The thermostatically controlled developing bath is agi­
tated mechanically for about half an hour, before receiving the
developing rack. During development the rack is manually agitated.
The monitoring films are developed together with unexposed controls
furnishing background density, and with a set of exposed processing
controls, with which the constancy of the developing solution is
checked. When not in use, the developer is protected from the
influence of oxygen by a floating lid. After three weeks or 5000 cm2
of developed film per 51 solution (whichever of the two occurs
earlier), the developer is discarded. Every time a new developing
batch is started, a complete set of calibration films is developed
along with the monitoring films and the processing controls.
Evaluation. The sum of the net densities of the sensitive and in­
sensitive films is determined. A calibration curve of density-us.exposure is plotted, from which the exposure corresponding to the
sum-densities may be read off immediately, without any knowledge
of photon energy. Fig. 2 shows the degree of compensation of the
energy-dependence of the film response which makes this procedure
* Kodak manufactures films in the United States of America, England and
France (Kodak-Pathe); films of the same type-designation made in the different
plants are similar, though not identical in their characteristics. Also, similar
films may have different designations in different countries; for instance, the
English type Kodirex is similar to the American type KK.
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LAYER (mm Cu)
Fig. 2
The data
5.1.1; degree of compensation of the
dependence of the film response
under perpendicular radiation
1 — Kodak film type M only; 2 — Kodak film type Kodirex
only; 3 — Sum response.
feasible. Where it seems desirable, one also plots sensitivity curves
for the two films densitometered separately. One then obtains an
indication of photon energy from the ratio of the densities of the
sensitive and insensitive films.
Exposure record. A record card is sent out to the individual users of
the service. It is made the responsibility of the user to record the
details of exposure, film number and film position at the end of each
monitoring period. The cards remain the personal property of the
Monitoring period. Two or four weeks, according to mutual agree­
ment between service and user.
Exposure range monitored. From 0.020 to 1.0 r over the photon
energy range from 0.025 to 2 MeV or more.
5.1.2 Second example
Film holder. Two sheets of tin, 2 mm thick, a hole perforated in one
corner, 0.025 mm aluminium foil, polyvinyl tubing, 0.3 mm thick.
Films. Ilford types N 550 and PM 2, cut to size 15 X 20 mm.
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Film-badge assembly. (See also Fig. 3.) The films are cut to the
correct size and wrapped in paper. The packet containing the more
sensitive film type PM 2 is sandwiched between the two sheets of
1 2
Fig. 3
Example 5.1.2; film badge
1 — Ilford N 550 film packet; 2 — 2 mm tin; 3 — Ilford PM 2 film
packet; 4 — 2 mm tin; 5 — Components (1) to (4), wrapped in
0.025 mm aluminium foil and inserted into a 0.3-mm polyvinyl tube;
6 — Complete package; 7 — For comparison only: dental film, normal
tin foil. The packet containing the less sensitive film type N 550 is
placed on top of the assembly, which is then wrapped in the alumi­
nium foil and inserted into the polyvinyl tube, together with a
numbered paper tab. Finally, the tube is sealed.
Badge identification. The paper tab carries the number of the user
and of the monitoring period. The films themselves are not num­
bered. The hole in the tin filter aids in the discrimination between
the sensitive and the insensitive film, since it produces a darker
dot on the sensitive film when the badge is exposed to low-energy
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Calibration. One set of films is given a fixed exposure (0.4 r) at
different radiation energies, using filtered X-rays produced at con­
stant exciting potentials between 50 and 250 kV, as well as Cs137
and Co60-gamma radiation. This exposure series yields curves
of badge response as a function of (effective) photon energy. An­
other set is given a series of different exposures at a fixed radiation
quality (150 kV constant exciting potential, added filtration: 1.0 mm
aluminium and 0.5 mm copper). This set yields a density-us.exposure curve for the evaluation of the exposure received by the
monitoring samples.
Processing. All calibration films, monitoring films and environmental
controls are developed simultaneously. Upon their return from the
monitoring stations the film packets are immediately placed in
compartments carrying the same numbers as the packets. These
compartments are used both as film-processing holders and for
convenient storage of the exposed film packets and films during
Fig. 4
Example 5.1.2
Compartments for storage and processing of exposed film packets and films
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manipulation (Fig. 4). This reduces the likelihood of confusing the
film samples in the darkroom, where they axe unwrapped one by one
and replaced into their own compartments. All calibration films,
monitoring films and environmental controls are developed simulta­
neously in a special tray which can carry about 1600 numbered
Evaluation. The sums of the net densities are determined. If the
sum-density is greater than 0.5, the films are also densitometered
separately. (This, along with the hole in the tin filters, facilitates
conclusions regarding radiation energy.) The further evaluation
proceeds as described in section 5.1.1.
Exposure record. Record cards are kept by the monitoring laboratory
for an indefinite period of time. The films themselves are not
Monitoring period. Two weeks.
Exposure range monitored. From 0.020 r to 4.0 r of X- and gammaradiation of photon energies between 0.03 and at least 1.25 MeV.
This range can be extended to approximately 40 r by measuring the
silver content of the films by means of quantitative X-ray fluor­
escence analysis.
5.1.3 Third example
This is a service falling into both classes 1-a and 2-b. The portion
falling into class 1-a is quite similar to the first service described
under 1-a, except that it is carried out for low-energy X-radiation
only. The portion falling into class 2-b is similar to other services
described in that class and therefore is not mentioned any further.
An interesting detail is the use of differently coloured badges for
successive monitoring periods, and also for different types of radia­
tion (X-ray badges, gamma-ray badges, gamma-ray and neutron
badges, etc.).
Also, the practice of supplying the new customers with two badges,
the one to be worn on the coat lapel, the other one on the sleeve,
may be worth mentioning. Once the habits of a particular customer
are known, only one badge is supplied which then is worn on the
one of these two locations that was found more likely to receive
the higher radiation exposures.
5.2 CLASS 1-b [33,52— 61]
5.2.1. First example
Film holder. The film holder consists of one piece of 0.5-mm alumi­
nium sheet formed so as to enclose the filter and the film packet.
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The front of the aluminium holder leaves one-fourth of the inserted
film packet uncovered (see Fig. 5). The filter assembly which slips
loosely into this holder consists of a sheet of lead 0.5 mm thick, bent
so as to line about one-fourth of its front and, the entire back of the
aluminium holder; and of a sheet of copper, 0.5 mm thick, bent so
Example 5.2.1; film badge
1 — 0.5 mm aluminium holder; 2 — 0.5 mm lead; 3 — 0.5 mm
copper; 4 — Film packet.
[Components (2), (3) and (4) are inserted into (1); the front
of one-fourth of the film packet remains uncovered.]
as to line one-half of the front and one-fourth of the back of the
aluminium holder. By this design both the differential absorption
properties of the metals and their differential electron emission are
utilized; the latter is of importance mainly for high-energy
Film. Kodak Ultra-Speed periapical dental X-ray film packet, type
Film-badge assembly. The film packet is slipped into the holder
between the filters.
Badge identification. The film packets and films are numbered
through pressure by means of a punch machine which stamps a five­
digit serial number on each film, identifying the monitoring station,
the department, and the individual monitored.
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Calibration. Characteristic curves are established for X- and gammaradiation of various qualities, including radium gamma-rays and
X-radiation of the following characteristics:
Constant exciting
Added filtration
Half-value layer
1.5 A1
2.5 A1
0.5 Cu -f 1 A1
1.6 A1
2.5 A1
0.9 Cu
The inherent filtration of the X-ray tube is 1.5 mm Be.
Processing. All calibration and monitoring films are developed
simultaneously by conventional time-temperature techniques. Seven
commercially available dental-film developing racks, supported by
a common frame, make it possible to develop 100 films simultane­
Evaluation. The proper density-us.-exposure curve is selected on
the basis of the density ratios on the monitoring film. Films exposed
to both low- and high-energy radiations are evaluated by first
determining the high-energy contribution as indicated by the density
under the lead portion of the film.
Exposure record. A special record form is submitted in duplicate
by the department requesting the monitoring service. After evalua­
tion of the exposures, one copy of the completed form is returned;
the original is kept by the monitoring service. A cumulative exposure
record is maintained for each individual monitored.
Monitoring period. One month.
Exposure range monitored. From 0.020 to 2.0 r.
5.2.2 Second example
Film holder. (See Fig. 6.) Plastic holder, with snap-fit closure, having
an open-window area, a 0.5-mm lead filter and a 0.12-mm copper
filter, both in front and in back.
Film. DuPont film packet type 545, containing film type 555.
Badge identification. Through pressure marking, visible on both the
packet and the film. The first two digits represent the wearing period
and the remaining five are film serial numbers. The wearer prints
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his name on the packet. No attempt is made to issue the same
number to a wearer each period; however, each period the names
and numbers are reported to the service for cross-referencing.
Calibration. Sets of films are exposed to filtered X-radiation and to
radium-gamma rays.
Processing. The customary time-temperature procedure is used, with
occasional manual agitation. A 2%> acetic-acid stop-bath is employed
between developing and fixing baths and a wetting agent before
drying. Special developing racks are employed, each containing
close to 500 films. (See Fig. 7.) Two such racks may be run through
the processing solutions simultaneously. A complete set of calibration
films as well as unexposed control films are processed with each
Evaluation. Plots are prepared of lead-absorber density vs. openwindow density for the various X- or gamma-ray exposure conditions
(Fig. 8), as well as of the corresponding characteristic curves for
the open-window area (Fig. 9). With the aid of the first plot, the
exposure condition of the calibration films most closely resembling
that of a particular monitoring film is determined from the ratio of
the density under lead and in the open-window area. The X- or
gamma-ray exposure to the monitoring film can then be determined
from the properly selected calibration curve of the second plot.
Occasionally, exposures to beta-rays are detected by a markedly high
open-window density, in the absence of an appreciable density under
the copper filter. In this case, the ratios of the densities under lead
Fig. 6
Example 5.2.2; film badge
1 — Film holder (plastic); 2 — 0.5 mm lead; 3 — 0.12 mm copper; 4 — Open
window; 5 — Film packet; 6 — Plastic lid snapping into position as shown in
the assembled badge.
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Fig- 7
Example -5.2.2
Film processing tack
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Fig. 8
Example 5.2.2; relationship between photographic density behind lead absorber
and at open window, obtained with different radiation qualities
Half-value layer
(mm Cu)
Constant exciting potential
radium-gamma rays
and copper are used for the determination of X- or gamma-radia'tion
quality, and a notation is made on the report about the presence of
Exposure records. Bi-weekly exposure reports are issued. Also, a
punched-card record is maintained for each subscriber, allowing the
classification of the recorded exposures by the monitored individuals’
age, sex and occupation, and by the location of the badge on the
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body or the extremities. At the end of each year, the cumulative
exposure is determined and the cards are punched in one of seven
cumulative-exposure-range categories.
Fig. 9
Example 5.2.2
Characteristic curves for open-window area, obtained with
different radiation qualities
(Curve designation: same as in Fig. 8.)
Monitoring period. Two weeks.
Exposure range monitored. From 0.040 to 20 r of radium gammaradiation, and of X-radiation, starting with radiation generated at
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70 kV constant exciting potential ( h v l : 0.13 mm copper), and going
up to radiation generated at 250 kV constant exciting potential
( h v l : 2.05 mm copper).
CLASS 1-c [27]
5.3.1 Example
Film holder. Front lid of 1.5 mm brass, with circular aperture in the
centre. Steel back, 0.6 mm thick, lined with a 0.1-mm lead foil along
three-quarters of its length, with an oblong slit cut across the centre,
intersecting the circular aperture in the front lid, when the lid is in
position. (See Fig. 10 for details.)
Fig. 10*
Example 5.3.1; film badge
1 — 0.6 mm steel; 2 — 0.1 mm lead
over 0.6 mm steel; 3 — Open slot;
4 — 1.5 mm brass; 5 — Circular aper­
Film. Ilford PM-1 film packet.
Film-badge assembly. Front and back portions slide shut along
narrow guides, sandwiching the film in-between. Note that the
* From ref. [27], used b y permission o f the Editors o f the British Journal o f R adiology.
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Fig. 11*
Example 5.3.1
Loading of the processing rack
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electron-emission method here employed works with any single-film
packet in which the area density of the paper wrapping in contact
with the lead foil does not significantly exceed 200 mg/cm2. In the
case of the Ilford PM-1 film the packet is accommodated in the
holder with the thinner wrapping facing the lead-lined back.
Badge identification. Each film holder carries a number engraved
on the front lid. This is the number permanently allotted to each
monitored individual. The wrapped films are numbered by means
of a commercial, hand-operated percussion press, having a six-digit
numbering head. There are two sets of holders having different
colour codes, which are distributed in successive monitoring periods.
Calibration. The routine calibration is carried out on bare film
packets, with X-radiation at an exciting potential of 100 kV and with
a 1.5-mm copper filter added to the inherent filtration equivalent to
1 mm Al. Also, an occasional check is made with a calibrated radium
source. The energy-dependence of the film response was obtained
at the time the present method of monitoring was adopted. Because
of the reproducibility of the energy-dependence from emulsion batch
to emulsion batch, regular re-checking of the energy-dependence
was found to be unnecessary.
Processing. All calibration and monitoring films are processed
simultaneously by conventional methods. A commercially available
processing rack holding close to 150 films is used (Fig. 11).
Evaluation. A photographic density-us.-exposure curve is plotted
from the data obtained at 100 kV exciting potential. Corresponding
curves of the responses as a function of energy are prepared, from
which the correction factors are obtained that are used to relate the
dose interpretation at any desired radiation quality to that obtained
from the density-us.-exposure curve for diagnostic X-radiation.
Criteria for the determination of radiation quality, and thus for the
selection of the proper correction factors, are provided by the visual
appearance of the pattern on the exposed film (see Figs. 12 and 13
for further details and explanations).
Exposure record. Exposure information is kept, along with informa­
tion on the blood picture.
Monitoring period. One week.
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Fig. 12*
Example 5.3.1
Patterns on exposed films
1 — Exposed to Na24; 2 — Exposed to radium; 3 — Exposed to radium, heavily
filtered; 4 — Exposed to Sr90.
[High energy is reliably indicated by negative contrast of backing slot and by
steel causing less density than lead. Aperture contrast in (1) and (2) is misleading
and is non-existent in (3).]
Exposure range monitored:
D ia g n o s t ic
X - rays
r a d ia t io n
fro m
250-kV therapy X-rays...............
G a m m a - rays f r o m
r a d iu m
0 .0 0 2
1 .0 r
0.005 mr to 2.0 r
radioactive isotopes
............... 0.015
............................. 0.015
B e t a - r a d ia t io n
to 13 r
13 r
In this class will be found only laboratories that rely to a relatively
small extent on personnel monitoring with photographic film, sup-
* From ref. [27], used b y permission o f the Editors o f the British Journal o f R adiology.
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Fig. 13*
Example 5.3.1
Patterns on exposed films
1 — Film worn by diagnostic radiographer (appearance of film typical of
diagnostic scatter: dark back-slot image, lead-steel border not visible, unsharp
aperture); 2 — Film worn by therapist (area over steel has larger density than,
that over lead, a sign of therapy-scatter); 3 — Film worn by diagnostic radio­
grapher exposed to diagnostic scatter and. to patients with radium insertions
(dark slot is evidence of low energy and steel-lead contrast of gamma-ray ex­
posure); 4 — Typical radium exposure for comparison with (3) and (5); 5 — Mix­
ture of gamma- and direct diagnostic X-rays (diagnostic component is suggested
by high definition of aperture edge and low slot-aperture contrast).
plementing it rather extensively with area surveys as well as with
other personnel-monitoring devices. Such devices are designed
particularly to give quick and reliable information about massive
* From ref. [27], used by permission o f the Editors o f the British Journal o f Radiology.
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fast- and thermal-neutron exposures, as well as massive gamma-ray
exposures, sudi as may occur, for instance, in criticality accidents
around reactors. Substances exhibiting specific neutron threshold or
resonance reactions are used in foil or pellet form for the determina­
tion of neutron fluxes and neutron energies [62]. Silver-activated
phosphate glass is a handy indicator of massive gamma-ray fluxes*
5.4.1 Example
Film, holder. A sheet of cadmium, 1 mm thick, a 0.18-mm plastic
sleeve to cover the film packet; an aluminium carrying case with
open front (Fig. 14).
Fig. 14
Example 5.4.1; film badge
1 — Duraluminium holder (0.48 mm); 2 — 1mm cadmium
(backed by 0.48 mm duraluminium from holder); 3 — Slot in
cadmium filter for ease of disassembling; 4 — Film packet;
5 — Plastic sleeve (0.18 mm); 6 — Open window.
[Components (2), (4) and (5) are inserted in (1).]
Films. DuPont film packet type 544, containing the film types 555
and 845.
* Such devices may also be incorporated right into film badges. A picture of
such a film badge is shown in Fig. 23, p. 72.
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Film-badge assembly. The sheet of cadmium is bent in such a way
that it snap-fits, both in front and back, over one-half of the film
packet, which is contained in the plastic sleeve. The whole assembly
slides into the carrying case.
Badge identification. Before issue the badges are serially stamped
on the wrapper with the employee-identity number and are also
dated. After collection the emulsions are stamped with the same
date and the identity number is written in in pencil.
Calibration. With Co60-gamma radiation. The energy-dependence of
the film response is checked with a number of different energy bands
of X-radiation.
Processing. Usual time-temperature procedure. Commercially avail­
able multiple-layer developing racks are used, which hold over 500
Fig. 15
Example 5.4.1
Processing rack
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individual films (see Fig. 15). The racks are not agitated during processing.
Evaluation. The exposure is determined from the density under the
cadmium filter. Checks have shown agreement in most cases to
within 20% between ion-chamber readings and the exposure inter­
pretations from the film badge obtained in this way.
An unusual feature of the service is the visual sorting method re­
placing densitometry for films having only background density. All
processed films are spread on a sheet of white paper, and those
having a density above background are selected visually. In this pro­
cedure, the operator relies to a certain extent on the recognition of
the abrupt density change occurring at the location underneath the
filter edge in films that had been exposed. A laboratory experiment
indicated that an experienced operator was able to sort, by this
method, films exposed to between 0 and 50 mr to within the accuracy
of a densitometer.
Exposure record. Exposure reports are prepared listing the exposures
greater or equal to 20 mr received during the bi-weekly monitoring
periods, as well as quarterly and calendar-year exposures, and run­
ning lifetime totals. A simple system using IBM accounting proce­
dures was developed for this purpose. Every worker receiving an
exposure of 20 mr or more in any one period is sent a postcard in­
forming him of the exposure.
Monitoring period. The routine monitoring period is two weeks;
however, workers regularly receiving relatively high exposures are
monitored on a weekly basis.
Exposure range monitored. From 0.020 to 500 r for photon energies
above 50 keV.
CLASS 2-b [23, 26, 38, 41, 64— 71]
5.5.1 First example
Film holder for beta-, X- and gamma-ray monitoring. Plastic case,
containing an open-window area, a leaded area for marking purposes,
and three filters: 1.0 mm Ag, 0.13 mm Ag, and 0.49 mm A1 (Fig. 16).
The thin silver shield and the aluminium shield are equal in mass
per unit area (about 0.3 g/cm2) and thus are essentially beta-equi­
Film holder for X-, gamma-ray and neutron monitoring. Plastic case,
containing an open window, and two filters: 1.0 mm cadmium and
1.0 mm tin.
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Fig. 16
Example 5.5.1; film badge
1 — 1.0 mm silver; 2 — Open window; 3 — 0.13 mm silver; 4 — 0.49 mm alu­
minium; 5 — 0.14 mm lead; 6 — Main body of badge holding set of back
Ulters; 7 — Film packet; 8 — Insert holding set of front filters; 9 — Plastic
slqeve for 10; 10 — Identification insert.
Films. DuPont film packet type 558, containing the film types 508
and 510; Kodak Personal Neutron Monitoring film, type A.
Film-badge assembly. Identical shielding is provided in front and
back of the film packet. The back portion of the badge is secured
to the main body of the badge by means of a magnetic lock. This
makes the badge “ tamper-proof” and, at the same time, makes it
possible to load and unload the badge automatically. The lead tape
next to the filters is used for radiographic film identification. A
photograph and other pertinent information identifying the wearer
of the badge fit onto the badge front.
Badge identification. One letter (for the location) and five digits
(for the payroll number) are perforated into the lead tape and are
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radiographed onto the film with grenz-rays from a unit operated
intermittently (IV2 seconds on, 372 seconds off) at 12.5 kV (peak) and
12.5 mA. An additional binary-code notching system is used to
designate the week and the year.
Calibration. Full characteristic curves are obtained with a rotating
source of radium gamma-radiation, and, for use around plutonium „
also with K-fluorescence radiation from zirconium (16 keV) and
tantalum (59 keV). A calibrated PUF4 source is used for the calibra­
tion of the nuclear-track film. Routinely, films are not calibrated
with thermal neutrons; the radium-gamma-ray calibration is used
instead, supplemented by the experimentally determined relation
between the films' thermal-neutron and gamma-ray response. A ura­
nium plaque is used for the beta-ray calibration.
Processing. Completely automatic film-processing equipment is used,
in which a chain drive and pneumatic arms automatically transport
the film racks through all processing steps, including drying (see
Fig. 17 for a picture of the racks). Built-in precision-timing
mechanisms and temperature control are part of the system. An acid
stop-bath is used between developer and fixer. The Solutions are used
for one month. The developer is replenished by restoring its; original
volume with ordinary fresh developing solution once a week. The
developing solution is agitated by a one-second nitrogen burst
emitted every 15 seconds from coiled tubing in the bottom of the
tank. Air is used in the same manner to agitate the stop-bath and
the fixing solution. The dryer is of the forced-air type.
Calibration films, monitoring films and unexposed control films are
developed simultaneously.
Evaluation. The evaluation of X- and gamma-ray exposure is done
with the aid of an electronic computer. Under a number of simplify­
ing assumptions (e. g. that no beta-radiation is received by films ex­
posed to low-energy X- or gamma-rays, that 16-keV radiation will not
produce a density under either of the silver shields, that 60-keV'
radiation will not produce a density behind the thick silver shield,
etc.), three simultaneous equations are set up that relate the densities
in the three film areas (open window, thin and thick silver shields) to
the exposures equivalent to radium gamma-radiation, and to 16-keV
and 60-keV X-rays. The coefficients are the slopes of the density-us.exposure curves for the three types of radiation, and are known from
the calibration data. The equations are then solved for the exposures
with the aid of the experimentally determined density values.
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Fig. 17
Example 5.5.1
Processing rack
Exposures to neutrons of energies greater than 0.8 MeV are
evaluated by having each of three observers count under the micro63
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scope the number of proton recoil tracks in 40 fields of view (i. e. in
an area of 0.31 cm2), under a magnification of 970 (oil immersion).
Films indicating a significant increase in the number of tracks rela­
tive to background are examined in a total of 400 fields. The upper
limit of the counts in a 90 °/o confidence interval is compared with the
lower limit in a similar interval obtained with 300 mrem on the same
area of the calibration films. (The average film response yields 71.24
± 13.51 tracks per 40 fields of view, equivalent to 1075 mrem, with
a 95°/o confidence.)
The thermal-neutron dose is evaluated from radium-gamma-ray
calibrations with the aid of an empirical relation for the ratio
between the gamma-ray and thermal-neutron doses producing the
same density behind a cadmium shield of a thickness of about
1.0 mm.
Exposure record. The records are programmed for electronic dataprocessing, allowing analysis of personnel exposure by job-function
and age, as well as by type of radiation. Annual as well as cumulative
exposure records are kept.
Monitoring period. Four weeks.
Monitoring range (for routine automatic operation):
0.016 MeV
...................................... From
0.005 to 0.160 r
0.059 MeV
...................................... From
0.005 to 0.080 r
From about 0.2 MeV up . .
. . From 0.015 to 1.0 r
B e ta -r a y s
...................................... From 0.015 to 1.0 rem
T h erm a l
F ast
n eu tron s
n eu tron s
.................... From
about 0.020 to 0.60 rem
............................. From
about 0.050 to more than 2 rem
(if fog from X - or gamma-rays is
The range of the X- and gamma-ray readings above 0.2 MeV and of
the beta-ray readings may be extended in emergency cases up to
2000 rem through quantitative X-ray fluorescence analysis [66].
5.5.2 Second example
Film holder for X- and gamma-ray monitoring. Commercially
available plastic holder; open window, number aperture, three
copper filters of thicknesses 0.05, 0.5 and 1.2 mm; 0.5-mm lead strip
between two of the copper filters. All but the number aperture and
the lead strips are symmetrical in front and back; the lead strips are
somewhat offset (see Fig. 18).
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Film holder for X-, gzmma-ray and neutron monitoring. Same holder
as for X- and gamma-rays only, but three more filters are present:
0.6 mm Sn, 1.2 mm Sn and 1.0 mm Cd. Also, the badge has a filterless portion which holds the nuclear-track film.
Example 5.5.2; film badge
1 — 0.5 mm copper; 2 — 0.05 mm copper; 3 — 1.2 mm copper;
4 — Open window; 5 — 0.5 mm lead; 6 — Aperture through
which number of the film packet is visible.
Films. Kodak Personal Monitoring Film, type 2; Kodak Personal
Neutron Monitoring Film, type B.
Film-badge assembly. The back of the badge is held in position by
a set screw; the number of the film packets shows through the
numbering slit.
Badge identification. A commercially available percussion-press
marks the outside of the packets as well as the films. A carbon ribbon
is used for better legibility on the outside. Pressure is exerted from
front and back.
(a) With X- and gamma-radiations, response is determined as a
function of photon energy by means of heavily filtered brems­
strahlung and gamma-radiation from Au198, radium (filtered with
1 cm lead) and Cofi0-gamma rays, in perpendicular incidence. A
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full characteristic curve is obtained with X-radiation generated
at about 80-kV exciting potential, with a total filtration of about
1 mm copper in the X-ray beam.
(b) In the case of beta-radiation, an attempt is made to calibrate
with the particular radiation used by the station that is to be
(c) The fast-neutron calibration is carried out with a Po-Be source
(2 c polonium). It is now planned to obtain a Pu-Be source
(3 c plutonium).
Processing. The films are connected to each other with tape in a
commercially available machine (Fig. 19), rolled on a developing
reel and processed in X-ray developer like cinematographic film. A
special nuclear-track developer [72] is used for the neutron films.
Example 5.5.2
Connecting individual dental films for processing on reel
Evaluation. Essentially, X- and gamma-ray exposure is evaluated
from the ratios of the exposures corresponding to the densities
obtained in the open-window area and under the three copper or
the two tin filters (or both), as a function of filter thickness. The
exposure is first determined from the measured densities by use of
the characteristic calibration curve obtained at 100 kV exciting
potential. It is then corrected for the energy-dependence of the film
response (Fig. 20) with the aid of a plot of the correction factors as
a function of the ratios of exposures required for unit density under
adjacent filter areas, as determined from the calibration curve. A rep­
resentative plot of correction factors is shown in Fig. 21. For filters
of the same material, these ratios are unique functions of the photon
energy. Therefore; when the X- and gamma-ray film holder is
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used, the ratios are determined from the densities under the dif­
ferent copper filters only; when the film holder designed to
monitor neutrons as well as X- and gamma-rays is employed, and
Fig. 20*
Example 5.5.2
Typical energy-dependence of a radiation-monitoring film
an evaluation is to be made of exposures obtained with very high
energies of X- and gamma-radiation, the ratios are determined from
the densities under the tin filters only.
In the absence of thermal neutrons, the areas under the same masses
of tin and cadmium show roughly the same density. The presence
of thermal neutrons is indicated by additional blackening under the
cadmium. The calibration with a known thermal-neutron flux makes
a quantitative evaluation of the thermal-neutron dose possible. The
differentiation between soft X- or gamma-rays and beta-radiation is
accomplished through the asymmetrical lead foil; in the presence of
large amounts of incident beta-rays or electrons causing massive
back-scatter from lead, the film area adjacent to the backing leadfoil is, as a rule, darker than the area that is covered with lead in
front, or any of the other adjacent areas.
The method of determining the fast-neutron dose is similar to that
described in the preceding example.
* From ref. [67], used by permission o f Verlag Karl Thiem ig KG, Munich.
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6 8 10
40 60
Fig. 21*
Example 5.5.2
Correcting for energy-dependence
1 — Ratio exposure for unit density at open window to exposure
for unit density under 0.05 mm Cu; 2 — Ratio exposure for unit
density under 0.05 mm Cu; 3 — Ratio exposure for unit density
under 0.5 mm Cu to exposure for unit density under 1.2 mm Cu.
Exposure record. The record is kept on a card-index system, which
makes the evaluation possible from a number of different points of
view. Monthly and annual exposure doses for different groups of
radiation workers are obtained with relatively little effort.
Monitoring period. One month, as a rule; for fast neutrons two
weeks, if desired.
Exposure range monitored:
L o w - e n e r g y X- a n d g a m m a - r a y s
(about 40 k eV ).............................
H i g h - e n e r g y X- a n d g a m m a - r a y s
T h erm a l n eu tron s
F a st
n eu tron s
0.002 to
150 r
0.040 to
1000 r
0.020 to 400 rem(provided
the X- and gamma-ray dose
was less)
0.020aJ to approx. 5.0
^ A p p lic a b le if the fog due to X - or gamma-ray exposure was negligible. The value
o f 0.02 rem is one-fifth o f the maximum perm issible weekly dose, based on a
40-hour week.
T c f.
[67], used by permission o f Verlag Karl Thiem ig KG, Munich.
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5.5.3 Third example
This is an example for a station not using photographic film but
photographic paper emulsions for personnel monitoring. Some of the
noteworthy features of the service are:
Film holder. A plastic envelope with “button holes” containing a
metal sleeve, that is to be slipped over one half of a dental-size film
packet. According to the type of radiation monitored, the sleeve
contains different filters. For the monitoring of hard gamma-rays
and neutrons, the sleeve contains: a cadmium filter, 0.35 mm in
thickness and a tin filter, 0.40 mm thick (see Fig. 22). For the
Fig. 22
Example 5.5.3; film badge
1 — 0.35 mm cadmium; 2 — 0.40 mm tin; 3 — Packet
containing photographic papers; 4 — Plastic envelope.
monitoring of soft X-rays these filters are replaced by two copper
filters, of thicknesses 0.2 and 0.6 mm, and for the approximate
discrimination between beta- and gamma-rays by a filter of 1 mm
Photo-sensitive material. Three strips of emulsions of differing
sensitivity, placed side by side on a paper base, which in turn is
mounted on a support of dental-film size, enclosed in a regular
dental packet. Manufacturer: Kodak-Pathe. Kodak Personal Neutron
Monitoring Film, type B, is employed for the monitoring of fast
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Badge assembly. In addition to the three emulsion strips, the sensitive
element carries a development-control strip which makes emergency
development under non-standard processing conditions feasible. The
packet with the filter sleeve is inserted into the plastic envelope,
which is then sealed.
Badge identification. Through pressure marking of the packet out­
side and inside, the inside on a special paper marking strip.
Processing. In the commercial developer recommended by KodakPathe for use with the particular photo-sensitive material.
Evaluation. Usually by visual comparison of the densities on the
monitoring strips with those on the calibration strips. The proton
recoil tracks are counted under a microscope (magnification factor
800, oil immersion, direct vision) by scanning a total length of 4 cm
of emulsion.
Calibration. Characteristic curves are established for various qualities
of X- and gamma-radiation, including radium-gamma rays (filtered
through 20 mm lead) and X-radiation having the following character­
Constant exciting
Added filtration
Half-value layer
The inherent filtration of the X-ray tube is 2 mm AI.
The thermal-neutron dose is evaluated from calibration checks
obtained by exposure of film badges in a reactor thermal column.
The neutron flux is determined by use of boron- and lithium-loaded
nuclear plates. A calibrated neutron flux from a radium-beryIlium
source is used for the fast-neutron calibration of the nuclear-track
Monitoring period. Usually two weeks.
Exposure range monitored:
X -ra y s
(< 1 8 0 k V )
G a m m a -r a y s
.................... From 0.010 r to between 25 and 40 r
From 0.010 r to 800 r
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T h erm al
F ast
n e u tron s
n eu tron s
.................... From 0.010 rem (or
dose) to 400 rem
(Sr90/Y 90,
filtered by 30m g/cm 2)
V io
of gamma-ray
From 0.040 rem to 100 rem
B e ta -r a y s
From 0.020 rad to 800 rad
5.5.4 Fourth example
This is an example of a station having a comprehensive film-badge
service, but nevertheless supplementing it with a complete set of
additional detectors, mainly for use in accidents.
Film holder. Fig. 23 shows the details of the holder construction.
Plastic, aluminium and lead, and cadmium interleaved with gold,
are used as filter materials. Further elements included, mainly for the
reliable analysis of neutron doses greater than 10 rad, are a sulphur
pellet, another gold foil, and an indium foil. A chemical dosimeter
and a silver-activated phosphate glass are also incorporated. Never­
theless, the over-all dimensions of the holder are only approximately
6.3 X 4.4 X 0.81 mm and it weighs about 33 grams. Note that there
is a layer of plastic between the film packets and the front filters
of the badge. Also, the identification insert (about 0.51 mm of plastic
and paper) is over the “open window” . In addition to this personnel
dosimeter, a set of stationary threshold detectors is used.
The rest of the film-dosimetry procedure is quite similar to what
was described in other examples.
5.5.5 Fifth example
This is another example of a station that has a complete film-badge
service supplemented with a complete set of additional detectors for
use in accidents."'
Film holder for beta-, X- and gamma-rays, and for thermal neu­
trons. (Fig. 24.) Hinged plastic case having an open window and
the following1absorbers: plastic, 300 mg/cm2 and 150 mg/cm2 re­
spectively (approximately 3 and 1.5 mm thick); duraluminium
1.0 mm; lead, 0.3 mm, plus tin, 0.7 mm; lead, 0.3 mm, plus cadmium,
0.7 mm. The “ slot” provided along one of the long sides of the
holder for strapping the badge to the wrist or other parts of the
body may also be used for attaching a “ criticality pack” for use in
the event of a reactor accident.
* In the planning stage at the time this Manual was written.
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Fig. 23
Example 5.5.4; film badge
1 — Main body of badge, plastic; 2 — 0.25 mm lead; 3 — Film packets; 4 — Phosphate glasses; 5 — Copper sleeve;
6 — Lead sleeve; 7 — Plastic; 8 — Sulphur; 9 — Gold; 10 — Open window; 11 — Combination: 0.38 mm cadmium —
0.13 mm gold — 0.38 mm cadmium; 12 — 1.0 mm aluminium; 13 — Identification insert (0.25mm indium); 14 — Chemi­
cal dosimeter; 15 — Plug; 16 — Badge number; 17 — Laminated identification insert; 18 — Front frame of badge.
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Fig. 24
Example 5.5.5; film budge
1 — 0.7 mm tin backed by 0.3 mm lead; 2 — 0.7 mm
cadmium backed by 0.3 mm lead; 3 — 1.0 mm dur­
aluminium; 4 — 3.0 mm plastic; 5 — 1.5 mm plastic; 6 —
Recess for indium foil; 7— Open window.
Also, a recess is provided for an indium foil, 0.5 mm thick, again for
criticality purposes.
Holder for fast-neutron plates. Flat disc-type holders, made of alumi­
nium, about 30 mm in diameter (Fig. 25).
Films. Kodak Radiation Monitoring Film is used for monitoring
beta-, X- and gamma-rays and for thermal neutrons. Ilford K 2
nuclear-track plates (emulsion thickness 50 um) cut to 25-mm squares
are used for fast-neutron monitoring.
Badge assembly. Noteworthy feature of the fast-neutron badge
assembly: two plates are placed with their emulsions facing each
other but separated by 0.25 mm polyethylene.
Badge identification. Pressure marking of film packets and films
Calibration. The energy-dependence of the badge response is de­
termined with narrow bremsstrahlung spectral bands in the
customary way, except that the badges are exposed at an angle of
45 degrees to the incident radiation which is thought to simulate
conditions under actual use more realistically than exposure under
perpendicular incidence. (Under these conditions of exposure the
variation of the film sensitivity under the lead-plus-tin or lead-pluscadmium filters as a function of photon energy is no more than
10°/o for “ effective” radiation energies above 90 keV.) Furthermore,
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Fig. 25*
Example 5.5.5
Holder for nuclear-track plates
a density-us.-exposure curve is prepared using radium gammaradiation, again for the film regions filtered by lead-plus-tin (or leadplus-cadmium).
The calibration for thermal neutrons is based upon response charac­
teristics originally established in a calibrated reactor thermal column.
A calibrated neutron flux from a radium-beryllium source is used
for the fast-neutron calibration of the nuclear-track plates.
Processing. For the development of the monitoring films, commer­
cially available developing frames, each accommodating 144 films,
are used. (See Fig. 11, p. 54.) The developer is replenished ac­
cording to the manufacturer’s instructions. Both developer and fixer
are discarded after the processing of 10 000 films. The nuclear-track
plates are processed in a special developer [26],
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Evaluation. The conventional procedure of comparing ratios of densi­
ties in the various areas of the monitoring films with those obtained
from calibration films is used for the evaluation of the beta-, X- and
gamma-ray exposures. The plastic filters aid in the discrimination of
beta-rays and soft X-rays; the duraluminium filter is used in the
X-ray region up to around 90keV; higher-energy X- or gamma-ray
exposures may be determined directly from the densities under the
lead-plus-tin (or lead-plus-cadmium) filter, without any correction
to be applied to the radium calibration curve.
The proton recoil tracks in the nuclear-track emulsion are counted
under the microscope with a magnification of roughly 1000, either
by direct vision or by projecting the image on a screen. Each plate
is scanned over an area of 0.014 cm2, and the dose is determined
by a comparison with the number of tracks counted over a similar
area of the calibration plate.
Exposure record. A statistics and reporting section maintains ad­
dress and movement cards for each individual monitored, as well as
a complete, coded, punched-card record system allowing for a fast
and easy analysis of cumulative exposure data.
Monitoring period. Two weeks.
Exposure range monitored:
around 0.040 MeV
. . . .
0.001 to 100 r
around 1 M eV
T h erm a l
F a st
n eu tron s
n eu tron s
0.020 to 2000 r
. .
0.010 to 1000 rem
(rb e
= 3)
............................. lower limit 0.050 rem, upper limit
depending on degree of X - or gammaray fogging (under severe conditions
as low as 3— 5 rem)
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.. Pocket dosimeters? Film badges? . . . or both?” ,
17 5 (1959)
[2] Safe Handling of Radioisotopes, Safety Series No. 1, STI/PUB. No. 1,
IAEA, Vienna (1958).
[3] EHRLIGH, M., Photographic Dosimetry of X - and Gamma Rays, Hand­
book 57, United States Dept, of Commerce, National Bureau of Standards
(1954); for sale by the Superintendent of Documents, Washington 25, D. C.
[4] Report of the International Commission on Radiological Units and Mea­
surements (ICRU), Handbook 78, United States Dept, of Commerce,
National Bureau of Standards (1961); for sale by the Superintendent of
Documents, Washington 25, D. C.
[5] MEES, C. E. K., ed., The Theory of the Photographic Process, revised
edition, the MacMillan Company, New York (1954).
[6] JOOS, G. und SCHOPPER, E., GrundriO der Photographie und ihrer Anwendung besonders in der Atomphysik, Akad. Verlagsges. m. b. H., Frank­
furt am Main (1958).
[7] BLATZ, H., ed.-in-chief, Radiation Hygiene Handbook, McGraw-Hill Book
Company, Inc., New York, Toronto, London (1959).
[8] American Standard Method for Evaluating Films for Monitoring X - and
Gamma Rays having Energies up to 2 Million Electron Volts; PH 2. 10
(1956) Photographic Standards Board, American Standards Association,
Inc., sponsor; to be purchased from American Standards Association, Inc.,
70 East 45th St., New York 17, N .Y.
[9] DEMERS, P., Ionographie, Les Emulsions Nucleaires, Principes et Applica­
tions, Les Presses Universitaires de Montreal (1958).
[10] M cLAUG H LIN, W . L. and EH RLICH , M., “ Film badge dosimetry: how
much fading occurs?” , Nucleonics 12 10 (1954) 34.
[11] TO M O D A , Y. and NAKAM URA, N., “ Latent image fading in gamma­
graphy”, J. Soc. sci. Photogr., Japan 21 (1958) 16 in Japanese; and
TO M O D A , Y., J. Soc. sci. Photogr., Japan 22 (1959) 12 in Japanese.
[12] ZIEGLER, G. A. and CHLECK, D .)., “ Latent-image fading in film badge
dosimeters”, Hlth Phys. 4 (I960) 32.
[13] EH RLICH , M., “Influence of temperature and relative humidity on the
photographic response to Co-60 gamma radiation”, J. Res. nat. Bur. Stand.
65 C (1961) 203.
[14] D U D LEY, R. A., “Photographic film dosimetry”, in Radiation Dosimetry,
G. J. Hine and G. L. Brownell, eds., Academic Press Inc., New York (1956).
[15] FLEE M AN , J. and FRANTZ, F. S., Jr., “ Film dosimetry of electrons in
the energy range 0.5 to 1.4 million electron volts” , J. Res. nat. Bur. Stand. 48
(1952) 117.
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[16] JETTER, E. S. and BLATZ, H., “ Film measurement of beta radiation
dose” , Nucleonics 10 10 (1952) 43.
[17] TO C H ILIN , E., SH U M W A Y, B .W . and KOHLER, G. D., “Response of
photographic emulsions to charged particles and neutrons” , Radiat. Res. 4
(1956) 467.
[18] HINE, G. J. and BR O W N ELL, G. L., eds., Radiation Dosimetry, Academic
Press Inc., New York (1956).
[19] Protection against Neutron Radiation up to 30 Million Electron Volts,
Handbook 63, National Bureau of Standards, National Committee on
Radiation Protection and Measurements (1957); for sale by the Super­
intendent of Documents, Washington 25, D. C.
[20] Measurement of Absorbed Dose of Neutrons and of Mixtures of Neutrons
and Gamma Rays, Handbook 75, National Bureau of Standards, National
Committee on Radiation Protection and Measurements (1961); for sale by
the Superintendent of Documents, Washington 25, D. C.
[21] JAEGER, R. H., Dosimetrie und Strahlenschutz, physikalische und tedinische Daten, Georg Thiemig-Verlag, Stuttgart (1959).
[22] HERCIK, F. and JAMMET, H., Safe Handling of Radioisotopes, Medical
Addendum, Safety Series No. 3, STI/PUB/11, IAEA, Vienna (1960).
[23] AM ADESI, P., RIM ONDI, O., SITAKI, H. e TURTURA, M. “ I service
di dosimetria personale del centro dosimetrico di Bologna” , Minerva
nucleate 4 11 (1960) 1.
[24] TO C H ILIN , E., DAVIS, R. H. and CLIFFORD, V. J., “A calibrated X-ray
film badge dosimeter” , Amer. J. Roentgenol. 64 (1960) 475.
[25] LAN G END O RFF, H., SPIEGLER, G. und W A C H SM AN N , F., „Strahlensdiutziiberwadiung mit Filmen", Fortschr. Rontgenstr, 77 (1952) 143.
[26] D EALLER, J. F. B., JONES, B. E. and SMITH, E. E., “ Personnel monitor­
ing for external radiation: a national service” , Occup. Safely & Hlth 8 3
(1958); to be obtained also from the International Labour Office, Geneva,
[27] SPIEGLER, G. and DAVIS, R., “An improved method and film holder
for personnel monitoring” , Brit. J. Radiol. 32 (1959) 464.
[28] ALLISY, J., «La mesure des doses de rayons X ou gamma a l’aide d’emulsions photographiques», J. Radiol. Electrol. 37 (1955) 249.
[29] EHRLICH, M., “A photographic personnel dosimeter for X-radiation in
the range from 30 KeV to beyond 1 M eV” , Radiology 68 (1957) 594.
[30] VAN STEKELENBURG, L. H. M., “New film badge enables cheaper X-ray
monitoring” , Nucleonics 16 (1958) 83; and “ De Filmbadgedienst van TN O ” ,
J. beige Radiol. 43 (1960) 209. .
[31] H OERLIN, H., CLARK, R. H., JONES, D. P., KASZUBA, F. J. and LAR­
SON, E. T., Development of a Wavelength-Independent Radiation Monitor­
ing Film: Final Report, ANL-5168 (1953).
[32] O’BRIEN, K., SOLON, L. R. and LO W D E R , W . M., “ Dose-rate dependent
dosimeter for low-intensity gamma-ray fields” , Rev. sci. Instrum. 29 (1958)
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[33] NIKITIN, N. S. i FROLOV, V. V., „ Usoversenstvovannij metod individual’nogo fotokontrolja gamma-vrednosti /IF K -II/“, Issledovandja v
Oblasti Dozimetrii ionizirujusfiih izlucenij: Sbomik Statej 680 (1957); see
also review in Referat 2ur. Elektroteknika, 3 (1959) 150, or its translation
in Nuclear Sci. Abstr. 13 (1959) 2987.
[34] EHRLICH, M. and M cLAUG H LIN, W . L., Photographic Dosimetry at
Total Exposure Levels Below 20 mr, Technical Note No. 29, National
Bureau of Standards, United States Dept, of Commerce, Office of Technical
Services, Washington 25, D. C. (1959).
[35] BECKER, K., „Probleme und Ergebnisse der Filmdosimetrie ionisierender
Strahlen“, Photogr. Korr. 96 6/7/8 (1960) Dr. Othmar Helwich, Darmstadt,
[36] BECKER, K., KLEIN, E. und ZEITLER, E., „Ein wellenlangenunabhangig registrierender Dosimeterfilm", Naturwissenschaften 47 (1960) 199.
[37] NELMS, A. T., Energy Loss and Range of Electrons and Positrons,
Circular 577 and Supplement, United States Dept, of Commerce, National
Bureau of Standards (1956, 1959); for sale by the Superintendent of
Documents, Washington 25, D. C.
[38] CHEKA, J. S., “Recent developments in film monitoring of fast neutrons” ,
Nucleonics 17 6 (1954) 40.
[39] EHRLICH, M., “The sensitivity of photographic film to 3-M eV neutrons
and to thermal neutrons” , Hlth Phys. 4 (1960) 113.
i SHTUKKENBERGA, Y. M., Sbornik Radiohimiceskih i Dozimetrideskih
Metodik, Ch. 8; Gosudarstvennoje Izdatel’stvo Medicinskoj Literaturi,
Medgiz, Moscow (1959).
[41] W IL SO N , R. H., M ILLIGAN, V. M., UNRUH, C. M. and LARSON, H. V.,
Gamma Calibration and Evaluation Techniques for Hanford Beta-Gamma
Film Badge Dosimeters, H W -71702, Hanford Laboratories Operation,
Richland, Washington (1961).
[42] Gaseous Burst Agitation in Processing, Pamphlet 57, Eastman Kodak
Company, Rochester, N. Y. (1956).
DRESEL, H., Die berufliche Strahlenbelastung, Strahlenschutz Nr. 11,
Schriftenwerke des Bundesministers fiir Atomenergie und Wasserwirtschaft,
Gersbach & Sohn Verlag G. m. b. H., Miinchen (1958, 1959).
[44] COWPER, G. and R O W E, P. C., Automatic Processing of Radiation Ex­
posure Data, CRRD-929, AECL No. 1052 (1960).
[45] EHRLICH, M. and FITCH , S. H.,
dosimetry” , Nucleonics 9 3 (1951) 5.
“Photographic X - and gamma-ray
[46] See, for instance, THOMPSON, L. C., Filtered X-Ray Spectra, NRL Re­
port 4743 (1956).
[47] SEEM ANN, H. E., “Spectral sensitivity of two commercial X-ray films
between 0.2 and 0.5 angstroms” , Rev. sci. Instrum. 21 (1950) 314.
[48] LARSON, H. V., MYERS, I. T. and ROESCH, W . C., “Wide-beam fluores­
cent X-ray source” , Nucleonics 13 11 (1955) 100.
[49] BASS, H., DI G IOVANN I, H. and LEV IN E , H. D., Extrapolation Chamber
Determination of Beta-Ray Surface Dose Rate for Uranium and Some
Uranium Compounds, AECD-2753 (1949).
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[50] BORTNER, T. E., Dose Rates of Radiation from Natural Uranium, O RNL740 (1950).
[51] M U EH LER, L. E. and CRABTREE, J. I., “ Materials of construction for
photographic processing equipment” , Photogr. Sci. and Techn. 19 B (1953)
79-88, 92-104.
[52] TO C H ILIN , E., DAVIS, R. H. and CLIFFORD, J., “A calibrated roentgenray film badge dosimeter” , Aimer. J. Roentgenol. 64 (1950) 475.
[53] BAKER, R. and SILVERM AN, L. B., “An improved film badge method for
the accurate determination of personnel exposures” , Nucleonics 7 1 (1951)
[54] FRISOLI, A. and SILVERM AN, L. B., “A new plastic tape film badge
holder” , Nucleonics 16 10 (1952) 62.
[55] Japanese Industrial Standards for “Badge Cases for X-Ray Dosimetry” ,
Z 4301 (1956); for “Hard X-Ray and Gamma-Ray Dosimetry” , Z 4302
(1957); for “ Characteristics of Photographic Emulsion for X-Ray Dosi­
metry”, K 7557 (1956); and “Characteristics of Photographic Emulsion for
Hard X-Ray Dosimetry and Gamma-Ray Dosimetry” , K 7779 (1958); in
[56] W A C H SM AN N , F. und SCHUBERT, W ., „Probleme und Fortschritte der
Strahlenschutziiberwachung nadi der Filmschwarzungsmethode“, Rontgenblatter 12 4 (1959) 1.
[57] M U SIA TO W IC Z, T., PENSKO, J. and WYSOPOLSKI, J., Personnel Film
Monitoring Service in Poland During the Year 1959, Report No. CLOR-3,
Warsaw (1960).
[58] NIKITIN, N. S., “O primenenii fotograficeskoj plenki dlja individual’nogo
dozimetriceskogo kontrolja potokov beta-castic” , Vestn. Rentgenol. i Radiol.
34 4 (1959) 59; see also review in Nuclear Sci. Abstr. 14 4 (1960) 475.
[59] PAIC, V., “A simple film badge, Institute ‘Rudjer Boskovic’ ” , Hlth Phi/s.
4 (1961) 180.
[60] FUJITA, M. and YAM AM O TO , M., “Gamma-ray dosimetry with film
badges” , Annual Report No. 2 of Health Physics Division, Atomic Energy
Research Institute, Japan, JAERI-5002 (I960).
[61] Verfahren zur Strahlensdiutzuberwachung nach der Filmschwarzungsmethode, D IN 006816, FadmormenausschuG Radiologie (FNR) im Deutschen NormenausschuB (DNA), Beuth Vertriebs Ges. m. b. H., Berlin, Koln,
Frankfurt am Main.
[62] TRICE, J. B., “ Measuring reactor spectra with thresholds and resonances” ,
Nucleonics 16 (1958) 81.
[63] SCH ULM AN, J. H., GINTHER, R. J. and KLICK, C. C., “ Dosimetry of
X-rays and gamma-rays by radio-photoluminescence” , J. appl. Phi/s. 22
(1951) 1479.
[64] Film Badge Service Instruction Manual, A EE T/R M L/1, Atomic Energy
Establishment Trombay (1959).
[65] SOUDAIN, G., «Perfectionnements dans la dosimetrie individuelle par
emulsions photographiques», Health Physics in Nuclear Installations, Riso
Symposium 1959, European Nuclear Energy Agency, OEEC, Paris, p. 95.
[66] BAUM GARTNER, W . Y. “An X-ray spectrometry method for evaluating
doses to 2000 r on film” , Nucleonics 18 8 (1960) 76.
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[67] DRESEL, H., „Praktisdie Bestimmung der Personendosis mit photographischen Emulsionen in Rontgen-, Isotopen- und Reaktorbetrieben“ , Kerntechnik 2 (1960) 239.
[68] DAVIS, D. M., GUPTON, E. D. and HART, J. C., “Criticality accident
application of the Oak Ridge National Laboratory badge dosimeter” ,
Hlth Phys. 5 (1961) 57.
[69] HURST, G. S. and RICHIE, R. H., Radiation Accidents, Dosimetric Aspects
of Neutron and Gamma Ray Exposures, ORNL-2748 (1959).
[70] FUJITA, M. and YAM AM O TO , M., “Development of a film badge for the
measurement of large neutron doses (Genken Type II badge)” , Annual
Report No. 2 of Health Physics Division, Atomic Energy Research Institute,
Japan, JAERI-5002 (1960).
[71] CIPPERLEY, F. V., “ Improvements in personnel-metering procedures at
the National Reactor Testing Station” , Hlth Phijs. 4 (1961) 173.
[72] FARAGGI, H., BO NNET, A. et CO HEN, M. J., irradiations et developpement des emulsions nucleaires exposees a des flux intenses de neutrons
thermiques accompagnes de rayons X», J. Phys. Radium, Supplement N ° 7
13 105 A (1952).
This publication is not longer valid
Please see
This publication is not longer valid
Please see
'- V i
VIENNA, 1962
Nuclear Safety and Environmental Protection/Radiological Safety
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