Model 575A
Amplifier
Operating and Service Manual
Printed in U.S.A.
ORTEC® Part No. 717460
Manual Revision C
1202
Advanced Measurement Technology, Inc.
a/k/a/ ORTEC®, a subsidiary of AMETEK®, Inc.
WARRANTY
ORTEC* warrants that the items will be delivered free from defects in material or workmanship. ORTEC makes
no other warranties, express or implied, and specifically NO WARRANTY OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR PURPOSE.
ORTEC’s exclusive liability is limited to repairing or replacing at ORTEC’s option, items found by ORTEC to
be defective in workmanship or materials within one year from the date of delivery. ORTEC’s liability on any
claim of any kind, including negligence, loss, or damages arising out of, connected with, or from the performance
or breach thereof, or from the manufacture, sale, delivery, resale, repair, or use of any item or services covered
by this agreement or purchase order, shall in no case exceed the price allocable to the item or service furnished
or any part thereof that gives rise to the claim. In the event ORTEC fails to manufacture or deliver items called
for in this agreement or purchase order, ORTEC’s exclusive liability and buyer’s exclusive remedy shall be release
of the buyer from the obligation to pay the purchase price. In no event shall ORTEC be liable for special or
consequential damages.
Quality Control
Before being approved for shipment, each ORTEC instrument must pass a stringent set of quality control tests
designed to expose any flaws in materials or workmanship. Permanent records of these tests are maintained for
use in warranty repair and as a source of statistical information for design improvements.
Repair Service
If it becomes necessary to return this instrument for repair, it is essential that Customer Services be contacted in
advance of its return so that a Return Authorization Number can be assigned to the unit. Also, ORTEC must be
informed, either in writing, by telephone [(865) 482-4411] or by facsimile transmission [(865) 483-2133], of the
nature of the fault of the instrument being returned and of the model, serial, and revision ("Rev" on rear panel)
numbers. Failure to do so may cause unnecessary delays in getting the unit repaired. The ORTEC standard
procedure requires that instruments returned for repair pass the same quality control tests that are used for
new-production instruments. Instruments that are returned should be packed so that they will withstand normal
transit handling and must be shipped PREPAID via Air Parcel Post or United Parcel Service to the designated
ORTEC repair center. The address label and the package should include the Return Authorization Number
assigned. Instruments being returned that are damaged in transit due to inadequate packing will be repaired at the
sender's expense, and it will be the sender's responsibility to make claim with the shipper. Instruments not in
warranty should follow the same procedure and ORTEC will provide a quotation.
Damage in Transit
Shipments should be examined immediately upon receipt for evidence of external or concealed damage. The carrier
making delivery should be notified immediately of any such damage, since the carrier is normally liable for damage
in shipment. Packing materials, waybills, and other such documentation should be preserved in order to establish
claims. After such notification to the carrier, please notify ORTEC of the circumstances so that assistance can be
provided in making damage claims and in providing replacement equipment, if necessary.
Copyright © 2002, Advanced Measurement Technology, Inc. All rights reserved.
*ORTEC® is a registered trademark of Advanced Measurement Technology, Inc. All other trademarks used
herein are the property of their respective owners.
iii
CONTENTS
WARRANTY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
SAFETY INSTRUCTIONS AND SYMBOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
SAFETY WARNINGS AND CLEANING INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
1. DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.1. GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2. POLE-ZERO CANCELLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3. ACTIVE FILTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
1
1
3
2. SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1. PERFORMANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2. CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3. INPUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.4. OUTPUTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.5. RELATED EQUIPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.6. ELECTRICAL AND MECHANICAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
4
4
4
4
4
5
3. INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1. GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2. CONNECTION TO POWER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3. CONNECTION TO PREAMPLIFIER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4. CONNECTION OF TEST PULSE GENERATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.5. SHAPING CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.6. LINEAR OUTPUT CONNECTIONS AND TERMINATING CONSIDERATIONS . . . . . . . . . . . . . .
3.7. SHORTING OR OVERLOADING THE AMPLIFIER OUTPUT . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
5
5
5
6
6
6
7
4. OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.1. INITIAL TESTING AND OBSERVATION OF PULSE WAVEFORMS . . . . . . . . . . . . . . . . . . . . . . 7
4.2. FRONT PANEL CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.3. PANEL CONNECTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.4. STANDARD SETUP PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.5. POLE-ZERO ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.6. OPERATION WITH SEMICONDUCTOR DETECTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.7. OPERATION IN SPECTROSCOPY SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.8. OTHER EXPERIMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5. MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.1. TEST EQUIPMENT REQUIRED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2. PULSER TEST* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3. SUGGESTIONS FOR TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4. FACTORY REPAIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5. TABULATED TEST POINT VOLTAGES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
15
15
16
16
16
iv
SAFETY INSTRUCTIONS AND SYMBOLS
This manual contains up to three levels of safety instructions that must be observed in order to avoid
personal injury and/or damage to equipment or other property. These are:
DANGER
Indicates a hazard that could result in death or serious bodily harm if the safety instruction is
not observed.
WARNING
Indicates a hazard that could result in bodily harm if the safety instruction is not observed.
CAUTION
Indicates a hazard that could result in property damage if the safety instruction is not
observed.
Please read all safety instructions carefully and make sure you understand them fully before attempting to
use this product.
In addition, the following symbol may appear on the product:
ATTENTION – Refer to Manual
DANGER – High Voltage
Please read all safety instructions carefully and make sure you understand them fully before attempting to
use this product.
v
SAFETY WARNINGS AND CLEANING INSTRUCTIONS
DANGER
Opening the cover of this instrument is likely to expose dangerous voltages. Disconnect the
instrument from all voltage sources while it is being opened.
WARNING Using this instrument in a manner not specified by the manufacturer may impair the
protection provided by the instrument.
Cleaning Instructions
To clean the instrument exterior:
! Unplug the instrument from the ac power supply.
! Remove loose dust on the outside of the instrument with a lint-free cloth.
! Remove remaining dirt with a lint-free cloth dampened in a general-purpose detergent and water
solution. Do not use abrasive cleaners.
CAUTION To prevent moisture inside of the instrument during external cleaning, use only enough liquid
to dampen the cloth or applicator.
!
Allow the instrument to dry completely before reconnecting it to the power source.
vi
1
ORTEC MODEL 575A AMPLIFIER
1. DESCRIPTION
1.1. GENERAL
The ORTEC 575A Amplifier is a single-width NIM
module that features a versatile combination of
jumper-selectable pulse-shaping characteristics.
The amplifier has extremely low noise, a wide gain
range, and excellent overload response for
univ ersal application in high-resolution
spectroscopy. It accepts input pulses of either
polarity. Input may originate from germanium or
silicon semiconductor detectors, from scintillation
counters with either fast or slow scintillators, from
proportional counters, from pulsed ionization
chambers, from electron multipliers, etc.
S
The unit has an input impedance of ~1000 and
accepts either positive or negative input pulses with
rise times <650 ns and fall times >30 s. Three
integration and differentiation time constants are
jumper-selectable on the printed wiring board
(PWB) to provide optimum shaping for resolution
and count rate. The differentiation network has
variable pole-zero cancellation that can be adjusted
to match preamplifiers with decay times >30 s.
The pole-zero cancellation drastically reduces the
undershoot after the differentiator and greatly
improves overload and count rate characteristics. In
addition, the amplifier contains an active, filtershaping network that optimizes the signal-to-noise
ratio and minimizes the overall resolving time.
:
:
The amplifier has unipolar and bipolar BNC outputs.
The unipolar output is used for spectroscopy in
systems where dc coupling can be maintained from
the 575A to the analyzer. A BLR (baseline restorer)
circuit is included in the unit for improved
performance at all count rates. Baseline correction
is applied only during intervals between input pulses
and automatically selects a discriminator level to
identify input pulses. The unipolar output dc level is
within the range of !5 mV to +5 mV. This output
permits the use of the direct-coupled input of the
analyzer with a minimum amount of interface
problems.
The 575A can be used for constant-fraction timing
when operated in conjunction with an ORTEC 551,
552, or 553 Timing Single-Channel Analyzer. The
ORTEC Timing Single-Channel Analyzers feature
a minimum of walk as a function of pulse amplitude
and incorporate a variable delay time on the output
pulse to enable the timing pick-off output to be
placed in time coincidence with other signals.
The 575A has complete provisions, including power
distribution, for operating any ORTEC solid-state
preamplifier. Normally, the preamplifier pulses
should have a rise time of 0.25 s or less to
properly match the amplifier filter network and a
s for proper pole-zero
decay time >30
cancellation. The input impedance is 1000 .
:
:
S
When long preamplifier cables are used, the cables
can be terminated in series at the preamplifier end
or in shunt at the amplifier end with the proper
resistors. The output impedance is ~0.2 , and the
output can be connected to other equipment by a
single cable going to all equipment. The cable must
be shunt-terminated at the far end. (See Section 3
for further information).
S
1.2. POLE-ZERO CANCELLATION
Pole-zero cancellation is a method for eliminating
pulse undershoot after the differentiating network.
In an amplifier not using pole-zero cancellation
(Fig. 1) the exponential tail on the preamplifier
output signal (usually 50 to 500 s) causes an
undershoot whose peak amplitude is roughly
determined from :
:
undershoot amplitude
differentiated pulse amplitude
=differentiation time
peramplifier pulse decay time
:
:
For a 1- s differentiation time and a 50- s pulse
decay time the maximum undershoot is 2%, and
this decays with a 50- s time constant. Under
overload conditions this undershoot is often
sufficiently large to saturate the amplifier during a
considerable portion of the undershoot, causing
excessive dead time. This effect can be reduced by
increasing the preamplifier pulse decay time (which
generally reduces the counting rate capabilities of
the preamplifier) or compensating for the
undershoot by providing pole-zero cancellation.
:
2
Pole-zero cancellation is accomplished by the
network shown in Fig. 2. The pole [s + (1/To)] due to
the preamplifier pulse decay time is cancelled by
the zero of the network [s + (k/R2C1)]. In effect, the
Fig. 1. Differentiation in an Amplifier Without Pole-Zero Cancellation.
Fig. 2. Differentiation in a Pole-Zero Cancelled Amplifier.
dc path across the differentiation capacitor adds an
attenuated replica of the preamplifier pulse to just
cancel the negative undershoot of the
differentiating network.
3
Total preamplifier-amplifier pole-zero cancellation
requires that the preamplifier output pulse decay
time be a single exponential decay and be matched
to the pole-zero cancellation network. The variable
pole-zero cancellation network allows accurate
cancellation for all preamplifiers having 30- s or
greater decay times. Improper matching of the polezero network will degrade the overload performance
and cause excessive pileup distortion at medium
counting rates. Improper matching causes either an
undercompensation (undershoot is not eliminated)
or an overcompensation (output after the main
pulse does not return to the baseline but decays to
the baseline with the preamplifier time constant).
The pole-zero adjust is accessible on the front
panel of the 575A and can easily be adjusted by
observing the baseline on an oscilloscope with a
monoenergetic source or pulser having the same
decay time as the preamplifier under overload
conditions. The adjustment should be made so that
the pulse returns to the baseline in the minimum
time with no undershoot.
:
Fig. 3; this waveform has characteristics superior to
the n = 2 Gaussian approximation, yet obtains them
with two complex poles and a real pole. By this
method, the output pulse shape has a good signalto-noise ratio, is easy to measure, and yet requires
only a practical amount of electronic circuitry to
achieve the desired results.
1.3. ACTIVE FILTER
When only FET gate current and drain thermal
noise are considered, the best signal-to-noise ratio
occurs when the two noise contributions are equal
for a given input pulse shape. The Gaussian pulse
shape (Fig. 3) for this condition requires an
amplifier with a single RC differentiation and n
equal RC integrations where n approaches infinity.
The Laplace transform of this transfer function is
G( s) =
s
1
×
(n → ∞),
s + (1 / RC) [s + (1 / RC)]n
where the first factor is the single differentiation,
and the second factor is the n integrations. The
active filter approximates this transfer function.
Figure 3 illustrates the results of pulse shaping in an
amplifier. Of the four pulse shapes shown the cusp
would produce minimum noise, but this is
impractical to achieve with normal electronic
circuitry and would be difficult to measure with an
ADC. The true Gaussian shape deteriorates the
signal-to-noise ratio by only about 12% from that of
the cusp and produces a signal that is easy to
measure but requires many sections of integration
(n64). With two sections of integration the
waveform identified as a Gaussian approximation
can be obtained, and this deteriorates the signal-tonoise ratio by about 22%. The ORTEC active filter
network in the 575A provides a fourth waveform in
Fig. 3. Pulse Shapes for Good Signal-to-Noise Ratios.
4
2. SPECIFICATIONS
2.1. PERFORMANCE
2.2. CONTROLS
GAIN RANGE Continuously adjustable from 5 to
1250.
FINE GAIN Ten-turn precision potentiometer with
graduated dial for continuously variable directreading gain factor of ×2.5 to ×12.5.
PULSE SHAPE Semi-Gaussian on all ranges with
peaking time equal to 2.2J, 50% pulse width equal
to 3.3 , and pulse width at 0.1% level equal to 4.0
times the peaking time. Bipolar crossover = 1.5 .
J
INTEGRAL NONLINEARITY
shaping time.
:
J
<±0.05% for 1.5-:s
:
NOISE <5 V rms referred to the input using 3 s
unipolar shaping; <7 V using 1.5 s shaping; both
for a gain $100.
:
:
TEMPERATURE INSTABILITY
Gain #±0.0075%/°C, 0 to 50°C.
Dc Level #±30 V/°C, 0 to 50°C.
:
:
WALK #±5 ns at 0.5 s shaping for 50:1 dynamic
range, including contribution of an ORTEC 551 or
552 Constant-Fraction Timing Single-Channel
Analyzer.
OVERLOAD RECOVERY Recovers to within 2%
of rated output from ×300 overload in 2.5
nonoverload pulse widths using maximum gain for
unipolar output. Same recovery from ×500 overload
for bipolar.
COARSE GAIN
Six-position switch selects
feedback resistors for gain factors of 2, 4, 10, 20,
40, and 100.
SHAPING TIME Three-position printed wiring
board (PWB) jumpers, easily accessible through
side panel, select time constants for active pulseshaping filter network of 0.5, 1.5, or 3 s.
:
POS/NEG Toggle switch selects either Pos or Neg
input pulse polarity.
PZ ADJ Screwdriver adjustable potentiometer to
set the pole-zero cancellation to compensate input
decay times from 30 s to 4.
:
2.3. INPUT
INPUT BNC (UG-1094A/U) front and rear panel
connectors accept either positive or negative pulses
with rise times of 10 to 650 ns and decay times of
dc-coupled; linear
30 s to 4; Zin = 1000
maximum 2 V; absolute maximum 20 V.
:
S
2.4. OUTPUTS
S
RESTORER Gated active baseline stabilizer with
automatic threshold circuit to provide the threshold
level as a function of signal noise to the baseline
restorer discriminator.
UNI Front panel BNC connector with Zo <1 and
rear panel connector with Zo = 93 . Short-circuit
proof; full-scale linear range of 0 to +10 V; active
filter shaped; dc-restored with dc level adjustable to
±25mV.
SPECTRUM BROADENING* Typically <10%
FWHM for a 60Co 1.33-MeV gamma line at 85% of
full scale for an incoming count rate of 1 to 50k cps.
Unipolar output, 1.5 s shaping.
BI Front panel BNC connector with Zo < 1 and
rear panel connector with Zo = 93 . Short-circuit
proof; positive lobe leading and full-scale linear
range of 0 to +10 V; active filter shaped.
SPECTRUM SHIFT* Peak position shifts typically
<0.02% for a 60Co 1.33-MeV gamma line at 85% of
full scale (measured at the unipolar output, 1.5 s
shaping, 1 to 50k cps).
PREAMP POWER Rear panel standard ORTEC
power connector (Amphenol 17-10090) mates with
captive and noncaptive power cords on all ORTEC
preamplifiers.
:
:
S
S
S
2.5. RELATED EQUIPMENT
*These count rate specifications were measured with a 10% HPGe detector.
Detectors with a large number of slow, rise-time signals will most likely give poorer
results.
The ORTEC 575A Amplifier accepts linear pulses
from, and furnishes power to, any standard ORTEC
preamplifier or equivalent. Its output pulses may be
used for linear signal analysis, using any of the
5
ORTEC modular instruments and multichannel
analyzers.
WEIGHT
Net 1.5 kg (3.3 lb).
Shipping 3.1 kg (7.0 lb.)
2.6. ELECTRICAL AND MECHANICAL
POWER REQUIRED +24 V, 55 mA;
mA; +12 V, 70 mA; !12 V, 75 mA.
!24 V,
40
DIMENSIONS Standard single-width NIM module
3.43 × 22.13 cm (1.35 × 8.714 in.) per TID-20893
(Rev).
3. INSTALLATION
3.1. GENERAL
The 575A operates on power that must be furnished
from a NIM-standard bin and power supply such as
the ORTEC 4001A/4002A Series. The bin and
power supply is designed for relay rack mounting.
If the equipment is to be rack mounted, be sure that
there is adequate ventilation to prevent any
localized heating of the components used in the
575A. The temperature of equipment mounted in
racks can easily exceed the maximum limit of 50°C
unless precautions are taken.
3.2. CONNECTION TO POWER
The 575A contains no internal power supply and
must obtain the necessary dc operating power from
the bin and power supply in which it is installed for
operation. Always turn off power for the power
supply before inserting or removing any modules.
After all modules have been installed in the bin and
any preamplifiers have also been connected to the
Preamp Power connectors on the amplifiers, check
the dc voltage levels from the power supply to see
that they are not overloaded. The ORTEC
4001A/4002A Series Bins and Power Supplies have
convenient test points on the power supply control
panel to permit monitoring these dc levels. If any
one or more of the dc levels indicates an overload,
some of the modules will need to be moved to
another bin to achieve operation.
3.3. CONNECTION TO PREAMPLIFIER
The preamplifier output signal is connected to the
575A through the Input BNC connectors on the front
and rear panels. The input impedance is ~1000
and is dc-coupled to ground; therefore, the
preamplifier output must be either ac-coupled or
have approximately zero dc voltage under no-signal
conditions.
S
The 575A incorporates pole-zero cancellation to
enhance the overload and count rate characteristics
of the amplifier. This technique requires matching
the network to the preamplifier decay-time constant
to achieve perfect compensation. The pole-zero
adjustment should be set each time the preamplifier
or the shaping time constant of the amplifier is
changed. For details of the pole-zero adjustment
see Section 4.5. An alternate method is
accomplished easily by using a monoenergetic
source and observing the amplifier baseline with an
oscilloscope after each pulse under ~×2 overload
conditions. Adjustment should be made so that the
pulse returns to the baseline in a minimum amount
of time with no undershoot.
Preamplifier power at +24 V, !24 V, +12 V, and
V is available through the Preamp Power
connector on the rear panel. When the preamplifier
is connected, its power requirements are obtained
from the same bin and power supply as is used for
the amplifier, and this increases the dc loading on
each voltage level over and above the
requirements for the unit at the module position in
the bin.
!12
When the 575A is used with a remotely located
preamplifier (i.e., preamplifier-to-amplifier
connection through 25 ft or more of coaxial cable),
be careful to ensure that the characteristic
impedance of the transmission line from the
preamplifier output to the 575A input is matched.
Because the input impedance of the 575A is
~1000 , sending-end termination will normally be
preferred; the transmission line should be seriesterminated at the preamplifier output. All ORTEC
preamplifiers contain series terminations that are
either 93 or variable; coaxial cable type RG-62/U
or RG-71/U is recommended.
S
S
6
3.4. CONNECTION OF TEST PULSE
GENERATOR
THROUGH A PREAMPLIFIER The satisfactory
connection of a test pulse generator (such as the
ORTEC 419 Precision Pulse Generator or
equiv alent) depends primarily on two
considerations: the preamplifier must be properly
connected to the unit as discussed in Section 3.3,
and the proper input signal simulation must be
applied to the preamplifier. To ensure proper input
signal simulation, refer to the instruction manual for
the particular preamplifier being used.
DIRECTLY INTO THE 575A Since the input of the
575A has 1000- input impedance, the test pulse
generator will normally have to be terminated at the
amplifier input with an additional shunt resistor. In
addition, if the test pulse generator has a dc offset,
a large series isolating capacitor is also required
because the 575A input is dc coupled. The ORTEC
test pulse generators are designed for direct
connection. When any one of these units is used, it
should be terminated with a 100- terminator at the
amplifier input or be used with at least one of the
output attenuators set at In. (The small error due to
the finite input impedance of the amplifier can
normally be neglected.)
S
S
SPECIAL CONSIDERATIONS FOR POLE-ZERO
CANCELLATION When a tail pulser is connected
directly to the amplifier input, the PZ ADJ should be
adjusted if overload tests are to be made (other
tests are not affected). See Section 4.5 for the polezero adjustment. If a preamplifier is used and a tail
pulser is connected to the preamplifier test input,
similar precautions are necessary. In this case the
effect of the pulser decay must be removed; that is,
a step input should be simulated.
3.5. SHAPING CONSIDERATIONS
The shaping time constant on the 575A is
selectable by PWB-mounted jumpers in steps of
0.5, 1.5, and 3 s. The choice of the proper shaping
time constant is generally a compromise between
operating at a shorter time constant for
accommodation of high counting rates and
operating with a longer time constant for a better
signal-to-noise ratio. For scintillation counters, the
energy resolution depends largely on the scintillator
and photomultiplier, and therefore a shaping time
constant of about four times the decay-time
constant of the scintillator is a reasonable choice
(for Nal, a 1.5! s shaping time constant is about
optimum). For gas proportional counters, the
:
:
:
collection time is normally in the 0.5 to 5 s range
and a 1.5 s or greater time constant selection will
generally give optimum resolution. For surface
barrier semiconductor detectors, a 0.5! to 2! s
resolving time will generally provide optimum
resolution. Shaping time for Ge(Li) detectors will
vary from 1.5 to 6 s, depending on the size,
configuration, and collection time of the specific
detector and preamplifier. When a charge-sensitive
preamplifier is used, the optimum shaping time
constant to minimize the noise of a system can be
determined by measuring the output noise of the
system and dividing it by the system gain. The
575A has almost constant gain for all shaping
modes; therefore, the optimum shaping can be
determined by measuring the output noise with a
voltmeter as each shaping time constant is
selected.
:
:
:
3.6. LINEAR OUTPUT CONNECTIONS
AND TERMINATING CONSIDERATIONS
Since the 575A unipolar output is normally used for
spectroscopy, the unit is designed with the flexibility
to interface the pulse with an analyzer. A gated
baseline restorer (BLR) circuit is included in this
output for improved performance at all count rates.
The threshold for the restorer gate is determined
automatically, according to the input noise level.
The unipolar output dc level is 0 to ± 5 mV. Three
general methods of termination are used. The
simplest of these is shunt termination at the
receiving end of the cable. A second method is
series termination at the sending end. The third is a
combination of series and shunt termination, where
the cable impedance is matched both in series at
the sending end and in shunt at the receiving end.
The combination is most effective, but this reduces
the amount of signal strength at the receiving end
to 50% of that which is available in the sending
instrument.
To use shunt termination at the receiving end of the
cable, connect the output from the 575A front or
rear panels through 93- cable to the input of the
receiving instrument. Then use a BNC tee
connector to attach both the interconnecting cable
and a 100- terminator at the input connector of
the receiving instrument. Since the input
impedance of the receiving instrument is normally
1000 or more, the effective instrument input
impedance with the 100- terminator will be of the
order of 93 , and this will match the cable
impedance correctly.
S
S
S
S
S
7
For customer convenience, ORTEC stocks the
proper terminators and BNC tees, or they can be
ordered from a variety of commercial sources.
not be harmed. When the amplifier is terminated
with 100 , the maximum count rate consistent with
linear output is
S
3.7. SHORTING OR OVERLOADING THE
AMPLIFIER OUTPUT
The 575A output is dc-coupled with an output
impedance of ~0.2 . If the output is shorted with
a direct short circuit, the output stage will limit the
peak current of the output so that the amplifier will
S
Ratemax =
125 000 cps
τ
×
10
Vo
where Vo is the peak output pulse amplitude in volts
(V) and J is the shaping time in s.
:
4. OPERATION
4.1. INITIAL TESTING AND OBSERVATION
OF PULSE WAVEFORMS
Refer to Section 5 for information on testing
performance and observing waveforms at front
panel test points. Figure 4 shows typical output
waveforms.
cancellation; input linear amplitude range 0 to 2 V
with a maximum limit of ±20 V. Input impedance is
~1000 .
S
4.2. FRONT PANEL CONTROLS
GAIN A Coarse Gain switch and a Gain control (a
precision 10-turn locking potentiometer) select and
precisely adjust the gain factor for the amplification
in the 575A. Switch settings are ×2, 4, 10, 20, 40,
and 100. Continuous fine gain range is from ×0.5 to
×12.5 using markings of 500 through 1250 dial
divisions.
Using these controls collectively, the gain can be
set at any level from ×5 through ×1250.
Fig. 4. Typical Unipolar and Bipolar Output
Waveforms.
POS/NEG A toggle switch selects an input circuit
which accepts either polarity of pulses from the
preamplifier.
PZ ADJ A screwdriver control sets the pole-zero
cancellation to match the preamplifier pulse decay
characteristics. The range is from 30 s to 4.
:
SHAPING PWB jumpers, easily accessed through
the side panel, select equal integration and
differentiation time constants to shape the input
pulses. Settings are 0.5, 1.5, and 3 s. Illustrated
drawings and instructions for setting time-constant
jumpers are shown in Fig. 5.
:
4.3. PANEL CONNECTORS
INPUTS Accept input pulses to be shaped and/or
amplified by the 575A. Compatible characteristics;
positive or negative with rise time from 10 to
650 ns; decay time >30 s for proper pole-zero
:
Fig. 5. Settings for Time-Constant Jumpers.
8
OUTPUTS
UNI Front panel BNC connector with Zo<1 and
rear panel connector with Zo = 93 . Short-circuit
proof; full-scale linear range of 0 to +10 V; active
filter shaped; dc-restored with dc level adjustable to
±25 mV.
S
S
S
BI Front panel BNC connector with Z o < 1 and
rear panel connector with Zo = 93 . Short-circuit
proof; positive lobe leading and full-scale linear
range of 0 to +10 V; active filter shaped.
S
b. Observe the unipolar output with an
oscilloscope. Adjust the PZ ADJ control so that
the pulse trailing edges return to the baseline
without overshoot or undershoot (Fig. 6).
The oscilloscope used must be dc coupled and
must not contribute distortion in the observed
waveforms. Oscilloscopes such as Tektronix 453,
454, 465, and 475 will overload for a 10-V signal
when the vertical sensitivity is <100 mV/cm. To
prevent overloading the oscilloscope, use the clamp
circuit shown in Fig. 7.
PREAMP POWER Rear panel standard ORTEC
power connector (Amphenol 17-10090) mates with
captive and noncaptive power cords on all ORTEC
preamplifiers.
4.4. STANDARD SETUP PROCEDURE
a. Connect the detector, preamplifier, high-voltage
power supply, and preamplifier into a basic
system and connect the amplifier output to an
oscilloscope. Connect the preamplifier power
cable to the Preamp connector on the 575A rear
panel. Turn on power in the bin and power
supply and allow the electronics of the system to
warm up and stabilize.
b. Set the 575A controls initially as follows:
Shaping
Coarse Gain
Fine Gain
Pos/Neg
:
1.5 s
10
5.00
Match input
polarity
pulse
c. Use a 60Co calibration source; place it about
25 cm from the active face of the detector. The
unipolar output pulse from the 575A should be
about 8 to 10 V using a preamplifier with a
conversion gain (charge sensitivity) of
170 mV/MeV.
d. Readjust the Gain control so that the higher
peak from the 60Co source (1.33 MeV) provides
an amplifier output at ~9 V.
4.5. POLE-ZERO ADJUSTMENT
The pole-zero adjustment is extremely critical for
good performance at high count rates. This
adjustment should be checked carefully for the best
possible results.
USING A GERMANIUM SYSTEM AND 60Co
a. Adjust the radiation source count rate beween
2 kHZ and 10 kHz.
Fig. 6. Typical Waveforms Illustrating Pole-Zero
Adjustment Effects; Oscilloscope Trigger,
Internal Pos., 60Co Source with 1.33-MeV Peak
Adjusted ~9 V; Count Rate 3 kHz; Shaping Time
Constant 1.5 :s.
9
a. Connect the detector to be used to the
spectrometer system; that is, preamplifier, main
amplifier, and biased amplifier.
b. Allow excitation from a source of known energy
(e.g., alpha particles) to fall on the detector.
Fig. 7. A Clamp Circuit that can be used to Prevent
Overloading the Oscilloscope Input.
U S I N G S Q U A R E W AV E T H R O U G H
PREAMPLIFIER TEST INPUT
A more precise pole-zero adjustment in the 575A
can be obtained by using a square wave signal as
the input to the preamplifier. Many oscilloscopes
include a calibration output on the front panel, and
this is a good source of square wave signals at a
frequency of ~1 kHZ. The amplifier differentiates
the signal from the preamplifier so that it generates
output signals of alternate polarities on the leading
and trailing edges of the square wave input signal,
and these can be compared as shown in Fig. 8 to
achieve excellent pole-zero cancellation. Use the
following procedure:
a. Remove all radioactive sources from the vicinity
of the detector. Set up the system as for normal
operation, including detector bias.
b. Set the 575A controls as for normal operation;
this includes gain, shaping, and input polarity.
c. Connect the source of 1-kHz square waves
through an attenuator to the Test input of the
preamplifier. Adjust the attenuator so that the
575A output amplitude is ~9 V.
d. Observe the Unipolar output of the 575A with an
oscilloscope. Adjust the PZ ADJ control for
proper response according to Fig. 8. Use the
clamp circuit in Fig. 7. to prevent overloading
the oscilloscope input.
4.6. OPERATION WITH SEMICONDUCTOR
DETECTORS
CALIBRATION OF TEST PULSER An ORTEC
419 Precision Pulse Generator (or equivalent) is
easily calibrated so that the maximum pulse height
dial reading (1000 divisions) is equivalent to 10MeV loss in a silicon radiation detector. The
procedure is as follows:
Fig. 8. Pole-Zero Adjustment Using a Square W to
the Preamplifier.
c. Adjust the amplifier gain and the bias level of
the biased amplifier to give a suitable output
pulse.
10
d. Set the pulser Pulse Height control at the
energy of the alpha particles striking the
detector (e.g., set the dial at 547 divisions for a
5.47-MeV alpha particle energy).
e. Turn on the pulser and use its Normalize control
and attenuators to set the output due to the
pulser for the same pulse height as the pulse
obtained in step c. Lock the Normalize control
and do not move it again until recalibration is
required.
The pulser is now calibrated; the Pulse Height dial
reads directly in MeV if the number of dial divisions
is divided by 100.
AMPLIFIER NOISE AND RESOLUTION
MEASUREMENTS
As shown in Fig. 9, a
preamplifier, amplifier, pulse generator,
oscilloscope, and wide-band rms voltmeter such as
the Hewlett-Packard 3400A are required for this
measurement. Connect a suitable capacitor to the
input to simulate the detector capacitance desired.
To obtain the resolution spread due to amplifier
noise:
a. Measure the rms noise voltage (Erms) at the
amplifier output.
b. Turn on the 419 precision pulse generator and
adjust the pulser output to any convenient
readable voltage, Eo, as determined by the
oscilloscope.
Fig. 9. System for Measuring Amplifier and Detector
Noise Resolution.
capacitance to the input. The detector noiseresolution spread can be isolated from the amplifier
noise spread if the detector capacitance is known,
since
(Ndet)2 + (Nelec)2 = (Ntotal)2,
where Ntotal is the total resolution spread, and Nelec
is the electronic resolution spread when the detector
is replaced by its equivalent capacitance.
The detector noise tends to increase with bias
voltage, while the detector capacitance decreases.
The net change in resolution spread will depend
upon which effect is dominant. Figure 10 shows
curves of typical noise-resolution spread versus
bias voltage using data from several ORTEC silicon
surface-barrier semi-conductor radiation detectors.
The full-width-half-maximum (FWHM) resolution
spread due to amplifier noise is then
N ( FWHM ) =
2.35 E rms E dial
Eo
where Edial is the pulser dial reading in MeV, and
2.35 is the factor for rms to FWHM. For averageresponding voltmeters such as the Hewlett-Packard
400D, the measured noise must be multiplied by
1.13 to calculate the rms noise.
The resolution spread will depend on the total input
capacitance, because the capacitance degrades the
signal-to-noise ratio much faster than the noise.
DETECTOR
NOISE-RESOLUT ION
MEASUREMENTS The measurement just
described can be made with a biased detector
instead of the external capacitor that would be used
to simulate detector capacitance. The resolution
spread will be larger because the detector
contributes
both
noise
and
Fig. 10. Noise as a Function of Bias Voltage.
AMPLIFIE R
NOISE-RESOLUTION
MEASUREMENTS USING MCA Probably the
most convenient method of making resolution
measurements is with a pulse height analyzer, as
shown by the setup illustrated in Fig. 11.
11
The electronic noise-resolution spread can be
measured directly with a pulse height analyzer and
the mercury pulser as follows:
a. Select the energy of interest with an ORTEC
419 Precision Pulse Generator. Set the amplifier
and biased amplifier gain and bias level controls
so that the energy is in a convenient channel of
the analyzer.
b. Calibrate the analyzer in keV per channel, using
the pulser; full scale on the pulser dial is 10
MeV when calibrated as described above.
c. Obtain the amplifier noise-resolution spread by
measuring the FWHM of the pulser peak in the
spectrum.
Fig. 12. System for Detector Current and Voltage
Measurements.
Fig. 11. System for Measuring Resolution with a Pulse
Height Analyzer.
Figure 12 shows the setup required for current
voltage measurements. An ORTEC 428 Bias
Supply is used as the voltage source. Bias voltage
should be applied slowly and reduced when noise
increases rapidly as a function of applied bias.
Figure 13 shows several typical current voltage
curves for ORTEC silicon surface-barrier detectors.
When it is possible to float the microammeter at the
detector bias voltage, the method of detector
current measurement shown by the dashed lines in
Fig. 12 is preferable. The detector is grounded as in
normal operation, and the microammeter is
connected to the current monitoring jack on the 428
detector bias supply.
The detector noise-resolution spread for a given
detector bias can be determined in the same
manner by connecting a detector to the preamplifier
input. The amplifier noise-resolution spread must be
subtracted as described in “Detector NoiseResolution Measurements.” The detector noise will
vary with detector size and bias conditions and
possibly with ambient conditions.
CURRENT VOLTAGE MEASUREMENTS FOR Si
AND Ge DETECTORS The amplifier system is not
directly involved in semiconductor detector current
voltage measurements, but the amplifier serves to
permit noise monitoring during the setup. The
detector noise measurement is a more sensitive
method than a current measurement of determining
the maximum detector voltage that should be used
because the noise increases more rapidly than the
reverse current at the onset of detector breakdown.
Make this measurement in the absence of a source.
.
Fig. 13. Silicon Detector Back Current vs Bias Voltage
12
4.7. OPERATION IN SPECTROSCOPY
SYSTEMS
H I G H-RESO L UT I O N AL PHA-PART I CL E
SPECTROSCOPY SYSTEM The block diagram of
a high-resolution spectroscopy system for
measuring natural alpha particle radiation is shown
in Fig. 14. Since natural alpha radiation occurs only
above several MeV, an ORTEC 444 Biased
Amplifier is used to suppress the unused portion of
the spectrum; the same result can be obtained by
using digital suppression on the MCA in many
cases. Alpha-particle resolution is obtained in the
following manner:
a. Use appropriate amplifier gain and minimum
biased amplifier gain and bias level.
Accumulate the alpha peak in the MCA.
b. Slowly increase the bias level and biased
amplifier gain until the alpha peak is spread
over 5 to 10 channels and the minimum- to
maximum-energy range desired corresponds to
the first and last channels of the MCA.
c. Calibrate the analyzer in keV per channel using
the pulser and the known energy of the alpha
peak (see “Calibration of Test Pulser”) or two
known-energy alpha peaks.
d. Calculate the resolution by measuring the
number of channels at the FWHM level in the
peak and converting this to keV.
obtain resolutions from about 1 keV FWHM up
(depending on the energy of the incident radiation
and the size and quality of the detector).
Reasonable care is required to obtain such results.
Some guidelines for obtaining optimum resolution
are:
a. Keep interconnection capacitance between the
detector and preamplifier to an absolute
minimum (no long cables).
b. Keep humidity low near the detectorpreamplifier junction.
c. Operate the amplifier with the shaping time that
provides the best signal-to-noise ratio.
d. Operate at the highest allowable detector bias
to keep the input capacitance low.
Fig. 15. System for High-Resolution Gamma
Spectroscopy.
SC I N T I L L AT I O N - C O U N T E R G AMMA
SPECTROSCOPY SYSTEMS The ORTEC 575A
can be used in scintillation-counter spectroscopy
systems as shown in Fig. 16. The amplifier shaping
time constants should be selected in the region of
0.5 to 1.5 s for Nal or plastic scintillators. For
scintillators having longer decay times, longer time
constants should be selected.
:
Fig. 14. System for High-Resolution Alpha-Particle
Spectroscopy.
HIGH-RESOLUTION GAMMA SPECTROSCOPY
SYSTEM A high-resolution gamma spectroscopy
system block diagram is shown in Fig. 15. Although
a biased amplifier is not shown (an analyzer with
more channels being preferred), it can be used if
the only analyzer available has fewer channels and
only higher energies are of interest.
When a germanium detector that is cooled by a
liquid nitrogen cryostat is used, it is possible to
13
The block diagram in Fig. 17 shows a system of this
type. Analysis can be accomplished by
simultaneous acquisition of all data on a
multichannel analyzer or counting a region of
interest in a single-channel analyzer window with a
counter and timer or counting ratemeter.
4.8. OTHER EXPERIMENTS
Fig. 16. Scintillation-Counter Gamma Spectroscopy
System.
X-RAY
SPECTROSCOPY
USING
PROPORTIONAL COUNTERS Space charge
effects in proportional counters, operated at high
gas amplification, tend to degrade the resolution
capabilities drastically at x-ray energies, even at
relatively low counting rates. By using a high-gain,
low-noise amplifying system and lower gas
amplification, these effects can be reduced and a
considerable improvement in resolution can be
obtained.
Fig. 17. High-Resolution X-Ray Energy Analysis System
Using a Proportional Counter.
Block diagrams illustrating how the 575A and other
ORTEC modules can be used for experimental
setups for various other applications are shown in
Figs. 18, 19, and 20.
Fig. 18. Gamma-Ray Charged-Particle Coincidence Experiment.
14
Fig. 19. Gamma-Ray Pair Spectrometry.
Fig. 20. Gamma-Gamma Coincidence Experiment.
15
5. MAINTENANCE
5.1. TEST EQUIPMENT REQUIRED
The following test equipment should be used to
adequately test the specifications of the 575A
amplifier:
1. ORTEC 419 Precision Pulse Generator or 448
Research Pulser.
2. Tektronix 547 Series Oscilloscope with a type
1A1 plug-in or equivalent.
3. Hewlett-Packard 3400A rms voltmeter.
:
FUNCTIONAL CHECKS Set the 575A controls as
follows:
100
7.5
Neg
1.5 s
OVERLOAD TESTS Start with maximum gain,
J = 1.5 s, and a +10 V output amplitude. Increase
the pulser output amplitude by ×200 and observe
that the unipolar output returns to within 200 mV of
the baseline within 24 s after the application of a
single pulse from the pulser. It will probably be
necessary to vary the PZ ADJ control on the front
panel in order to cancel the pulser pole and
minimize the time required for return to the
baseline.
:
:
a. Connect a positive pulser output to the 575A
input and adjust the pulser to obtain +10V at the
unipolar output. This should require an input
pulse of 13.3 mV using a 100- terminator at
the input. Adjust PZ if necessary.
b. Change the input polarity switch to Pos and
then back to Neg while monitoring the output for
a polarity inversion.
c. Monitor the bipolar output for dc level of
<±5 mV; pulse shape should be bipolar. Return
to UNI.
d. Recheck the output pulse amplitude and adjust
if necessary to set it at +10 V with maximum
gain. Decrease the Coarse Gain switch stepwise
from 100 to 2 and ensure that the output
amplitude changes by the appropriate amount
for each step. Return the Coarse Gain switch to
100.
e. Decrease the Gain control from 7.5 to 2.5 and
check to see that the output amplitude
decreases by a factor of 2. Return the Gain
control to maximum at 7.5.
f. With the shaping jumpers set for 1.5 s
measure the time to the peak on the unipolar
output pulse; this should be 3.3 s (or 2.2J).
S
:
:
Fig. 21. Circuit Used to Measure Nonlinearity.
*See IEEE Standards No. 301-1976.
:
:
:
5.2. PULSER TEST*
Coarse Gain
Gain
Input Polarity
Shaping Time Constant
Measure the time to baseline crossover of the
bipolar output; this should be 5.0 s (or 3.3J).
g. Change the shaping jumpers to 0.5 and 3 s in
turn. At each setting, check to see that the time
to the unipolar peak is 2.2J. Return the jumpers
to 1.5 s.
16
LINEARITY The integral nonlinearity of the 575A
can be measured by the technique shown in
Fig. 21. In effect, the negative pulser output is
subtracted from the positive amplifier output to
cause a null point that can be measured with
excellent sensitivity. The pulser output must be
varied between 0 to 10 V, which usually requires an
external control source for the pulser. The amplifier
gain and the pulser attenuator must be adjusted to
measure 0 V at the null point when the pulser
output is 10 V. The variation in the null point as the
pulser is reduced gradually from 10 V to 0 V is a
measure of the nonlinearity. Since the subtraction
network also acts as a voltage divider, this variation
must be less than
(10 V full scale) × (±0.05% maximum nonlinearity)
×(1/2 for divider network)
=±2.5 mV for the maximum null-point variation.
OUTPUT LOADING Use the test setup of Fig. 21.
Adjust the amplifier output to 10 V and observe the
null point when the front panel output is terminated
in 100 . The change should be <2.5 mV.
S
NOISE Measure the noise at the amplifier unipolar
output with maximum amplifier gain and 3- s
shaping time. Using a true-rms voltmeter, the noise
should be <5 V × 750 (gain), or 3.75 mV.
:
:
can be completely removed from the module to
enable oscilloscope and voltmeter observations.
5.4. FACTORY REPAIR
This instrument can be returned to the ORTEC
factory for service and repair at a nominal cost. Our
standard procedure for repair ensures the same
quality control and checkout as for a new
instrument. Always contact Customer Services at
ORTEC, (865) 483-2231, before sending in an
instrument for repair to obtain shipping instructions.
A Return Authorization Number is required and will
be assigned to the unit. This number should be
marked on the address label and on the package to
ensure prompt attention when the unit reaches the
factory.
5.5. TABULATED TEST POINT VOLTAGES
The voltages given in Table 5.1 are intended to
indicate typical dc levels that can be measured on
the PWB. In some cases the circuit will perform
satisfactorily even though, due to component
tolerances, there may be some voltage
measurements which differ slightly from the listed
values. The tabulated values should not be
interpreted as absolute voltages but rather should
be used as an aid during troubleshooting.
Table 5.1. Typical dc Voltages
For an average responding voltmeter, the noise
reading would have to be multiplied by 1.13 to
calculate the rms noise. The input must be
during the noise
terminated in 100
measurements.
S
Note: All voltages measured with no input signal,
with the input terminated in 100 , and all
controls set fully clockwise at maximum.
S
Location
5.3. SUGGESTIONS FOR
TROUBLESHOOTING
In situations where the 575A is suspected of a
malfunction, it is essential to verify such
malfunction in terms of simple pulse generator
impulses at the input. The unit must be
disconnected from its position in any system, and
routine diagnostic analysis performed with a test
pulse generator and oscilloscope. It is imperative
that the testing not be performed with a source and
detector until the amplifier performs satisfactorily
with the test pulse generator.
The testing instructions in Section 5.2 should
provide assistance in locating the region of trouble
and repairing the malfunction. The two side plates
T1
T2
T3
T4
T5
T6
T7
Voltage
±50 mV
±60 mV
±0.7 V
±1.0 V
±60 mV
0 to ! 0.8 V
±6 mV
17
Bin/Module Connector Pin Assignments
For Standard Nuclear Instrument Modules
per DOE/ER-0457T.
Pin
1
2
3
4
5
6
7
8
9
*10
*11
12
13
14
15
*16
*17
18
19
20
21
22
Function
+3 V
!3 V
Spare bus
Reserved bus
Coaxial
Coaxial
Coaxial
200 V dc
Spare
+6 V
!6 V
Reserved bus
Spare
Spare
Reserved
+12 V
!12 V
Spare bus
Reserved bus
Spare
Spare
Reserved
Pin
23
24
25
26
27
*28
*29
30
31
32
*33
*34
35
36
37
38
39
40
*41
*42
G
Function
Reserved
Reserved
Reserved
Spare
Spare
+24 V
!24 V
Spare bus
Spare
Spare
117 V ac (hot)
Power return ground
Reset (Scaler)
Gate
Reset (Auxiliary)
Coaxial
Coaxial
Coaxial
117 V ac (neutral)
High-quality ground
Ground guide pin
Pins marked (*) are installed and wired in
ORTEC’s 4001A and 4001C Modular System
Bins.