GettysburgCollegeProtonAcceleratorLaboratorySafetyProgram

GettysburgCollegeProtonAcceleratorLaboratorySafetyProgram
Gettysburg
College
Proton
Accelerator
Laboratory
Safety Program
Table of Contents
I.
II.
III.
IV.
V.
VI.
VII.
Scope and Application
Responsibilities
A. President/Provost of Gettysburg College
B. Environmental Health & Safety Officer
C. Radiation Safety Officer
D. Accelerator Laboratory Supervisor
E. Accelerator Operator
F. Safety Committee
Training
Accelerator Description
Radiation Safety Surveys
A. Initial Survey
B. Periodic Operator Surveys
Personnel Dosimetry
Accelerator Operating Procedures
A. Accelerator Startup Procedures
B. Accelerator Shutdown Procedures
1. Emergency Shutdown Procedure
2. Normal Shutdown Procedure
C. Accelerator Tank Gas Filling/Emptying Procedures
D. Vacuum System Procedures
VIII.
IX.
Accelerator Maintenance
Record Keeping
A. Training Records
B. Operator Logbook/Maintenance Records
C. Annual Audits
Appendix A:
Appendix B:
Appendix C:
Proton Accelerator Operator Safety Training Certification
Radiation Survey Report
Proton Accelerator Laboratory Facility Layout
I.
Scope and Application
All researchers, students, or others who use the Gettysburg College Proton
Accelerator Laboratory are required to comply with this document, to ensure
radiation exposure to accelerator users is as low as reasonably achievable
(ALARA) and well within the limits established by the Pennsylvania
Department of Environmental Protection’s Bureau of Radiation Protection.
II.
Responsibilities
A. The President of Gettysburg College has the ultimate responsibility for
radiation safety within the institution. General oversight responsibility is
assigned to the Provost of the College.
B. The Environmental Health & Safety Officer advises on matters of
radiation safety policies and practices and:
1.
establishes policies on the safe use of the accelerator.
2.
ensures the accelerator is licensed/annually renewed
according to state law.
3.
reviews operational procedures and annual audits of the
safety program to determine compliance with Pennsylvania
Department of Environmental Protection.
4.
reviews incident analyses involving the use of the accelerator
to determine the cause and take necessary corrective actions
to prevent reoccurrence.
5.
maintains records required to meet compliance with federal,
state, and local regulations.
C. The Radiation Safety Officer has a primary responsibility for
implementing this safety program and:
1.
providing individual workers with training, advice, and
assistance on all matters pertaining to the safe use of the
accelerator (training may be designated to lab supervisors by
the RSO).
2.
reviewing work practices to determine compliance with
regulations and approved procedures.
3.
assuring that all required radiation monitoring and protective
devices are calibrated, in place, and used appropriately.
4.
assuring the integrity of all accelerator systems through
regular inspection and testing.
5.
performing incident analyses involving the use of the
accelerator.
6.
maintaining calibration and training records.
7.
ensuring that all required signs and labels are applied.
8.
providing supervision and assistance for the management of
emergency situations.
9.
performing an annual audit of the accelerator safety program
to determine that all activities are being conducted safely and
reporting findings in a written report to the environmental
health & safety officer.
10.
terminates any operation involving the use of the accelerator
which he/she deems unsafe.
11.
has the authority to approve individuals with the requisite
experience and knowledge as authorized users (laboratory
supervisors).
D. The Accelerator Laboratory Supervisors (authorized users) are those
faculty members under whose instruction the particle accelerator is used.
The supervisor has a primary responsibility for assuring the safe use of the
accelerator, including but not limited to:
1.
complying with and enforcing the accelerator safety program.
2.
assuring that all personnel are properly trained in the safe use
of the accelerator.
3.
assuring that any new procedures for use of the accelerator
are submitted to the radiation safety officer for review before
initial testing/implementation.
4.
maintaining the required accelerator logbook, maintenance
records, and circuit diagrams.
5.
performing any required radiation safety surveys and report
results in the operator’s logbook.
6.
reviewing in advance all lab procedures using the accelerator.
7.
maintaining records required by the radiation safety officer or
the environmental health & safety officer.
E. All Accelerator Operators (including accelerator laboratory supervisors
and students working under their direct supervision) are responsible for:
1.
following the procedures prescribed in this document for
operating the accelerator. Failure to do so is a serious breach
of college policy and subject to disciplinary action that might
include termination of employment at the college. The
procedures to be followed in the event of such action shall be
in keeping with existing guidelines as stated in the
appropriate handbook for faculty, administrators, staff, or
students.
2.
completing the required accelerator use logbook at each time
of operation.
3.
reporting any malfunction, no matter how slight, to the
accelerator laboratory supervisor in charge before resuming
use of the accelerator.
F. The Gettysburg College Safety Committee assists the environmental
health & safety officer and:
1.
annually reviews the radiation safety program.
2.
conducts safety audits.
III.
Training
A. Accelerator Laboratory Supervisors are qualified professionals who by
their educational backgrounds and work experience Gettysburg College
and the Pennsylvania Department of Environmental Protection recognize
as having had the radiation training necessary to safely operate the
accelerator in accordance with this document and the accelerator
instruction manual.
B. All Accelerator Operators who are not designated as authorized users on
the state license must work under the direct supervision of an authorized
user and:
1.
complete general radiation safety training which ensures the
operator:
a.
has a basic knowledge of the different types of ionizing
radiation,
b.
understands the sources of potential radiation in the
Gettysburg College Proton Accelerator Laboratory
c.
understands the risks from occupational radiation
exposure,
d.
understands the units of radiation dose,
e.
understands the measures that can be taken to protect
against exposure to radiation, including specific,
procedures the college has implemented such as work
practices, emergency procedures, and personal
protective equipment to be used,
f.
understands the purpose and function of monitoring
equipment,
g.
understands the applicable details of the Gettysburg
College Proton Accelerator Safety Program and the
accelerator instruction manual,
2.
complete site-specific “hands-on” training in accelerator
operation under the supervision of an accelerator laboratory
supervisor, and
3.
complete laboratory safety training.
When the accelerator laboratory supervisor or radiation safety officer have
reason to believe that an operator who has been trained does not have the
understanding and skill required to safely operate the proton accelerator, the
operator must be retrained. Circumstances where retraining is required
include, but are not limited to, situations where:
1.
2.
changes in the laboratory render previous training obsolete.
changes in the work practices, emergency response or the
type of protective equipment used render previous training
obsolete.
3.
IV.
inadequacies in an operator’s knowledge or use of
equipment indicate that the operator has not retained the
requisite understanding and skill to safely operate the
accelerator.
Accelerator Description
The accelerator and operator controls are located in Masters Hall, Room 106
(Appendix C). This machine, model PN250, was manufactured by High
Voltage Engineering Corporation, Burlington, MA. A copy of the unit
instruction manual is available in the accelerator lab and contains a complete
description of its construction and capabilities. All accelerator operators are
required to review this in addition to any other training.
The primary radiation source is expected to be X-rays from back-streaming
electrons created by the interaction of the proton beam with residual gas atoms
within the acceleration tube. The accelerator tank is constructed of 1 cm thick
steel lined with ¼” lead, which will stop essentially all X-rays below 250 keV.
X-rays can also be produced when the proton beam interacts with certain
target materials. It is expected that the 1"-thick aluminum walls of the target
chamber will prevent exposure from these potential X-rays. Actual radiation
levels are determined from radiation surveys.
V.
Radiation Safety Surveys
A. Initial Survey Results
An initial radiation survey conducted by Dr. Bret Crawford at full energy
(250kV) showed all radiation levels to be below the 2-mR/hr standard for
public radiation exposure.
A possible source of major exposure is that of neutron-producing
reactions. For accelerators under 2 MeV such reactions are rare except
when deuterium or tritium is used as a target or projectile. We do not have
such targets, nor do we have deuterium as a source gas for the ion source
for the accelerator. Therefore, there are no neutrons produced by this
facility.
Another potential problem would be if the machine were used to produce
electron beams. This machine is not capable of running negative voltages,
so no electron beams are produced.
B. Periodic Operator Surveys
During normal operation, accelerator supervisors will monitor the lab prior
to the start of the fall semester, spring semester, and summer research
session to ensure radiation levels remain ALARA. Survey readings will
be recorded in the operators’ logbook and reported in the annual audit to
the environmental health & safety officer.
All surveys will be performed using a properly calibrated survey meter
capable of measuring the x-ray radiation emitted. Survey meters will be
sent out for calibration annually.
VI.
Personnel Dosimetry
According to federal and state regulations, persons likely to receive
radiation exposure levels at 10% or more of the annual limit of 5
Rem/year must be assigned to wear a personnel dosimeter during work
with the accelerator. The initial survey conducted by Dr. Crawford
indicates all exposures are below the public dose limit of 2 mRem/hr, and
therefore a personnel dosimetry program will not be necessary.
VII.
Accelerator Operating Procedures
The radiation safety officer shall retain the authority to modify details of the
operating procedures given below as needed to maintain safe and effective use
of the accelerator laboratory.
Accelerator operation is controlled by a key system. The accelerator key is
kept in a combination locked box in the accelerator lab. Only accelerator
laboratory supervisors know the combination to the lock box. A logbook is
located at the accelerator controls. This log is completed by the accelerator
operator each time the system is used. This log indicates the operator, date,
time on/off, and all necessary operating parameters. This data will assist the
accelerator laboratory supervisor in monitoring the accelerator system safety
on a continuous basis.
No one will be allowed to perform any maintenance, repairs, or modifications
until the accelerator laboratory supervisor has given permission to do so.
Records of all maintenance, repair, and modifications will be maintained by
the accelerator laboratory supervisor. Operation and service of the
accelerator will always be in accordance with High Voltage Engineering
PN250 accelerator operators’ manual and with the instruction of the
accelerator laboratory supervisor.
The radiation safety officer shall be informed of all abnormal events and
departures from normal use of the accelerator, which harm or have the
potential to harm humans or the environment.
A. Accelerator Start-up Procedure
(See PN-250 Instruction Book for details.)
1. Scan Operator Logbook for any anomalous running conditions.
2. Log starting date and time.
3. Log tank pressure (between 90 and 100psi). If not at appropriate
pressure see Tank Gas Filling Instructions
4. Log vacuum level on Accelerator Tube line, left of gate valve (<4x10-6
Torr). If tube is not under vacuum, see Vacuum System Instructions.
5. Obtain Control Key from lock box.
6. Check that Belt Charge control (big knob in the center) is completely
counter-clockwise. Turn key clockwise and toggle upward the start
switch.
7. After motor has gotten up to speed (you’ll hear the starting capacitor
relay drop out), you are ready to turn Belt Charge knob to reach the
desired terminal voltage. See Energy Calibration chart in Operator’s
Logbook to convert micro-amp reading of terminal-voltage meter to
actual beam energy.
8. Adjust Gas control to desired gas pressure.
9. Adjust Beam (probe voltage) and Focus controls to maximize beam
current.
10. Once at running energy, log beam energy, up-charge current, column
current, corona current, and beam current.
B. Accelerator Shutdown Procedure
(See PN-250 Instruction Book for details.)
Emergency Shutdown
1. Toggle downward the Control Power switch.
2. Remove key and place back in lock box.
3. When safe to do so, log emergency conditions in Operator
Logbook and contact the radiation safety officer.
Normal Shutdown
1. Slowly rotate the Belt Charge control counter-clockwise taking note of
the Total Charge and Voltage meters. As charge leaks off the dome,
the voltage should approach zero.
2.
3.
4.
5.
6.
7.
Bring the Beam control (probe voltage) to zero.
Bring the Focus control voltage to zero.
Toggle downward the Control Power switch.
Remove key and place it back in lock box.
Log Stop time in Operator Logbook.
Comment on any abnormal running conditions in Operator Logbook.
C. Accelerator Tank Gas Filling/Emptying Procedures
•
Fill Directly from source bottle
1. Evacuate accelerator tank with roughing pump.
2. Regulator on source bottle should be fully counter-clockwise.
3. Open valves 1 and 2 (in line from source bottle to accelerator
tank).
4. Open valve on top of source bottle and slowly rotate regulator
control clockwise to control flow (do not allow the line to freeze).
Fill tank to 95—100 psig.
5. Close valves 1 and 2, return regulator to fully counter-clockwise,
and close valve on top of source bottle.
6. Release pressure in gas line with pressure-relief valve.
•
Fill Directly from storage tank
1. Evacuate accelerator tank with roughing pump.
2. Open valves 8, 7, and 4 (in line from storage tank to accelerator
tank, bypassing the compressor).
3. Slowly open valve 1 to allow gas pressures between the accelerator
tank and storage tank to equalize.
4. Once pressure has equalized, close valve 4.
5. Open valves 3 and 5. Note: now valves 8, 7, 5, 3, and 1 are open.
6. Start compressor.
7. When storage tank is empty, turn compressor OFF.
8. Close valves 1, 3, 5, 7, and 8 (all valves closed).
9. If needed, fill from source bottle as per directions.
10. Release pressure in gas line with pressure-relief valve.
•
Empty into storage tank
1. Evacuate storage tank with roughing pump.
2. Open valves 8, 7, and 4.
3. Slowly open valve 1 to allow gas pressures between the accelerator
tank and storage tank to equalize.
4. Once pressure has equalized, close valves 3 and 7.
5. Open valves 5 and 6. Note: now valves 1, 4, 5, 6, and 8 are open.
6. Start compressor.
7. When accelerator tank is empty, turn compressor OFF.
8. Close valves 1, 4, 5, 6, and 8 (all valves closed).
9. Release pressure in gas line with pressure-relief valve.
D. Vacuum System Procedures
There are two pumping stations: one for the Acceleration Tube to the left
of the gate valve, one for the remainder of the beam line to the right of the
gate valve. The latter includes the target chamber. The accelerator may
be operated with the target chamber up to air, so long as the gate valve is
closed. The gate valve is interlocked with the vacuum meters such that
both lines have to be <5x10-5 Torr for the gate valve to open. If either
pressure rises, the gate valve will close automatically. However, since the
gate valve may not close fast enough to protect the turbo pumps and/or
Acceleration Tube, one should not rely on the interlock. Always double
check vacuum pressures before making a change to the vacuum
system.
1. Check that the gate valve is closed (upper panel of control rack). If
not, close it.
2. Turn on vacuum pressure meters (power switch is at the rear of the
Gauge Controller).
3. Press CHAN to scroll through the 4 thermocouple gauges (1 =
A.Tube, 2=Chamber, 3,4 = not used) and the 2 penning gauges (1
= A. Tube, 2 = Chamber). The thermocouple gauges read
pressures >10-3 Torr. The penning gauges read pressures <10-3
Torr. If up to air, you should read 760 Torr on the appropriate
thermocouple gauge. If not, press the ATM button to recalibrate
the thermocouple.
4. Double check that the line you wish to evacuate is closed up. If so,
press START on the relevant Pump Control Box (left box = A.
Tube). This will start the turbo pump and its associated backing
pump.
5. When the thermocouple gauge falls into the 10-2 to 10-3 Torr range,
press CHAN to the relevant penning gauge and press EMIS. You
may have to wait and press EMIS again, possibly several times,
until the penning gauge measures a current.
6. Log Start time in Operator Log.
Bringing a vacuum line up to air:
1. Press CHAN on the Gauge Controller to monitor the beam line you
wish to bring up to air.
2. Press EMIS to turn OFF the penning gauge.
3. Press the START button on the relevant Pump Control Box (left
box = A. Tube). The green light above the button will go out, but
the pump will continue to spin as it slowly winds down. Once the
pressure is high enough, the vent valve will be automatically
opened.
4. Log Stop time in Operator Log.
VIII.
Accelerator Maintenance
Maintenance on the Gettysburg College Proton Accelerator will be performed
in house by or under the direct supervision of the authorized users identified
on the state license.
Most maintenance problems are described in the Model PN Positive Ion
Accelerator Instruction Book (HVI-368, High Voltage Engineering
Corporation, Burlington, MA) or in the Gettysburg College Proton
Accelerator Laboratory Maintenance Logbook.
Whenever maintenance is performed, including pre-semester and annual
preventative maintenance as described below, details should be logged in the
GCPAL Maintenance Logbook.
Station
Daily
Preventative Maintenance Inspection Chart
Component
Action
Log only abnormal conditions.
Generator
Tank
Check buffer gas and replenish to 100psi if
below 90psi.
All Stations
System
Inspect by eye and ear for signs of wear or
abnormal operation.
Check tank-cooling water.
Log in Maintenance Logbook.
All Stations
System
Annually
(pre-summer)
Generator
Check-run using Operator’s Procedure.
Check for signs of abnormal noise.
Check mechanical pump oil.
Check turbo pump cooling fans.
Log in Maintenance Logbook.
Belt
Inspect for frayed sides, burns, deterioration,
Pre-Semester
and replace if necessary.
Vacuum Sys.
Operator Cntrl.
Motor
Check freedom of rotation; replace bearings if
needed.
Alternator
Check freedom of rotation; replace bearings if
needed.
Lightly oil alternator mount screws.
Belt Chg. Ass’y
Remove, clean, inspect screen; replace if worn.
Term. Collector
Remove, clean, inspect screen; replace if worn.
Column Resistors
Remove, clean, inspect for broken and/or loose
resistors, good contact. Replace as necessary.
Gradient Bars
Clean bars.
Column
Clean and inspect insulators.
Accelerator Tube
Check spark gaps and tube clips.
Tube Connectors
Check for position.
Tank
Blow out, check surfaces and repair burned
areas.
Terminal Shell
Clean and polish.
Terminal
Inspect electronics for signs of excessive
heating.
Ion Source
Circuit
Inspect for signs of wear or burning.
Retune before closing up.
Mechanical
pumps
Total yearly hours run from Operator Logbook.
Check oil.
Turbo pumps
Total yearly hours run from Operator Logbook.
Control Cabinet
Open and blow out. Visually inspect for loose
and/or burned contacts.
Log annual hours run.
Accelerator base
Open and blow out. Visually inspect for loose
and/or burned contacts.
Beam Optics
IX.
Steerers
Inspect for evidence of excessive heating.
Quads
Inspect for evidence of excessive heating.
Record Keeping
A. Training Records
The radiation safety officer will maintain records of all employees who
have attended radiation training. Training dates, times, locations, and
participants will be included in the annual audit submitted to the
environmental health & safety officer.
B. Operator Logbook and Maintenance Records
The Operator Logbook and maintenance records for the proton accelerator
shall be maintained in the Gettysburg College Proton Accelerator
Laboratory.
C. Annual Program Audits
The environmental health & safety officer will maintain records of annual
audits of the Gettysburg College Proton Accelerator Safety Program,
including results of periodic radiation surveys.
Appendix A
Proton Accelerator Operator Safety Training Certification
By signing this certification form at a training session, you acknowledge that you are
aware of the Gettysburg College Proton Accelerator Laboratory Safety Program and the
policies and procedures applicable to the safe operation of the High Voltage Engineering
PN250 Proton Accelerator, and you have attended a training session by the radiation
safety officer or his/her designate.
I have received training in the use of the High Voltage Engineering PN250 Accelerator.
This training included the following topics:
•
•
•
•
•
•
•
knowledge of the different types of ionizing radiation
sources of potential radiation in the Gettysburg College Proton Accelerator
Laboratory
risks from occupational radiation exposure
units of radiation dose
measures that can be taken to protect against exposure to radiation, including
specific procedures the college has implemented such as work practices,
emergency procedures, and personal protective equipment to be used
the purpose and function of monitoring equipment
applicable details of the Gettysburg College Proton Accelerator Safety
Program and the accelerator instruction manual
Name:__________________________________________________________________
Signature:_______________________________________________________________
Today’s Date:____________________________________________________________
Accelerator Laboratory Supervisor’s Name:____________________________________
Name of Trainer:__________________________________________________________
Signature of Trainer:_______________________________________________________
Today’s Date:____________________________________________________________
Appendix B
Radiation Survey Report
Spring _______
Summer _______
Fall _______
Has the instrument operated since completion of the last survey report? _____ Y_____N
(If Answer is No, a survey report is not necessary)
Operating Energy _____keV
Beam Current _____µA
Vacuum Pressure_____Torr
Surveyor__________________________________ Date_________________________
Location
1
2
3
4
5
6
7
8
Description
Back of Tank
One meter from Control Side of Tank
One meter from Compressor Side of Tank
Control Rack
Bending Magnet
Target Chamber
Surface of Tank
Accelerator Output
Survey Reading (µR/hr)
Appendix C
Accelerator Lab Facility Layout
358"
217"
offices
Room 106
Room 108
electronics
shop
156"
hall
accelerator
laboratory
electronics
laboratory
outside
machine shop
Room 104
380"
134"
71"
13"
acc
ele
rato
r
bed
table
table
acc
ele
rato
r
air
compressor
accelerator
control rack
storage
bending
magnet
target
chamber
storage
storage
storage
table
file
cabinet
90"
90"
16"
18"
acc
ele
rato
r
133"
27"
21"
acc
ele
rato
r
50"
75"
6"
air
compressor
17"
file
cabinet
22"
bed
table
table
25"
26"
accelerator
control rack
23"
358"
bending
magnet
23"
69"
storage
table
67"
30"
43"
36"
106"
storage
20"
24"
target
chamber
31"
129"
46"
41"
storage
storage
25"
36"
217"
36"
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