CAMD Radiation Safety
Training Manual
Author : Dr. Lorraine Day
Copyright 漏 1999 by [L.Day and K. Bangalore].
Table of Contents INTRODUCTION
Introduction This booklet is contains informational materials to
Regulations and help you prepare for the radiation safety test
Hierarchy available on the CAMD web page:
CAMD Access
Computer Access Radiation Safety Test
card You must receive a score of at least 80% in order to
Experimental Hall be able to obtain a radiation badge from the
Door radiation safety office and a computer access card
Experimental Hall from the CAMD facility manager.
Radiation production
at CAMD
ALARA
Radiation
Monitoring
Radiation Exposure
Units
Quality factors
Risk assessment
General safety tips
Personnel Safety
Tips
REGULATIONS AND HIERARCHY
Highlights
The CAMD Safety Officer reports to two separate
Regulations and individuals regarding safety. These are the Radiation
Hierarchy
Safety Officer for the University, and the Campus
CAMD Safety
Safety Officer in all other matters. Thus safety is
LSU Radiation Safety
independent from the CAMD administration. This
Officer
permits the CAMD safety office to make decisions
LSU Radiation Safety
Committee regarding the safe operation of the facility in an
LSU System Radiation unencumbered manner.
Safety Committee
The CAMD safety officer reports to the campus
Department of
Radiation Safety Officer for the university in all
Environmental Quality -
matters pertaining to radiation safety. When the CAMD
Radiological Protection
safety officer is unavailable, this office is in charge of
Division
radiation safety at CAMD.
Whenever changes in operation are made or alterations
which might affect the overall radiation safety of
CAMD personnel, these changes are discussed and
approved by the LSU (Baton Rouge Campus)
Radiation Safety Committee. In cases where no
decision is reached or an event has occurred then the
matter will be forwarded to the LSU System Radiation
Safety Committee.
Louisiana is what is termed an "agreement state" in that
is does not report directly to the Nuclear Regulatory
Commission. Thus the DEQ or Department of
Environmental Quality is the highest level of
authority for matters pertaining to radiological
protection. It is this body which gives CAMD its license
to operate the accelerators. If at any time you feel that
CAMD safety is not doing everything possible to
protect its workers from radiation, you may call the
state department of environmental quality - radiation
protection division at the following telephone number:
(504) 765-0160.
Our license to operate stipulates that all persons
working at CAMD will receive radiation safety training
and that said persons shall be re-trained yearly. Persons
not attending the annual refresher training course will
be denied access to the experimental hall and will lose
their badge until such time as they have received re-
training from the CAMD safety office.
CAMD ACCESS
The CAMD facility is opened from approximately 6:30
Highlights AM until 6 PM in the evening. Access during these times
may occur through either the gray door facing the parking
CAMD Access lot or via the double glass doors facing the park area.
Normal Operating Access to the experimental hall requires that the person
Hours have an active security card. Such cards may be obtained
6:30 AM-6:00 PM only after radiation safety training and approval of your
hours CAMD contact person. A sheet signed by the CAMD
Experimental Hall safety officer is supplied to a trained individual. This sheet
computer card is then transferred to the CAMD Facility Manger who will
issue the security access card. Radiation safety badges are
After Hours Access:
also ordered following this training. A person may remain
Approval as a guest of the CAMD facility for up to one week
Gate Key without a badge provided they are always accompanied by
Access Code a badged individual.
Radiation Training Individuals who are not members of a state supported
institution, must sign an indemnification agreement as part
of their radiation training. It is the responsibility of the
person being trained to inform the CAMD safety officer if
he/she is not a member of a state-supported institution.
Some individuals may request after hours access to the
building. Such access requires approval by the CAMD
director who must sign the access sheet. Additionally, the
individual must apply to receive a key to the gate and an
access code to the building. Normally such privileges are
reserved for CAMD staff or faculty.
Persons wishing to receive radiation safety training should
contact their CAMD contact person (i.e. the person with
whom you will be working while at CAMD). The contact
person will then contact CAMD safety to set up a training
schedule. The information requested will include, name,
date of birth and social security number. The date of birth
is required to ascertain that persons working in the CAMD
laboratory are at least 18 years of age. Exceptions have
been made and can be made for minors under 18 years of
age.
Once a radiation badge has been issued from the LSU
radiation safety office, you will be requested to sign a
form stating that you have never been exposed above the
allowable limit. If you have been exposed, then your
radiation records must be retrieved before you can begin
work at CAMD.
THE SECURITY ACCESS CARD
Highlights The security access card is obtained from the
facility manager after he/she has received
The Security Access proof of radiation safety training and an active
Card radiation badge has been assigned to that
Requires: individual.
Radiation safety The security access card is a tiered computer
training level card as follows. Upon completion of
Contact person radiation safety training, the card is issued
approval which permits entrance to the experimental
Signature hall only. Those individuals who wish to
Returned when you access the facility after normal operating hours
leave must obtain prior written permission from the
Tiered Access CAMD director.
Security access cards are coded for the
Experimental
Hall. experimental hall, for after hours access and
for cleanroom access. Cleanroom access
Clean Room requires separate training following radiation
safety training. Further, your project must be
After Hours
approved by the CAMD director before access
Access
to the cleanroom is obtained.
After radiation safety training testing
(computer based), print out your results and
bring them to the CAMD Facility Manager.
You must receive a minimum of 80% on the
radiation safety test before you can obtain your
security access card. You will be asked to sign
for this card before it can be activated. Further,
when you leave CAMD, this card should be
returned to the Facility Manager or to your
CAMD contact person.
Highlights EXPERIMENTAL HALL DOOR
At the entrance to the experimental hall , a computer
Experimental Hall Door
monitor and several signs are posted. Most noticeable of
Computer Moniter
these is the computer monitor which is located to the right
Stored Beam
Injection
of the door at about 7 feet above the floor. This monitor
Flashing White and Red
displays the mode of operation of the machine. Two main
Sign
screens are possible. The first displays the exponential
Door Announcements
Caution Radiation
decay of stored beam with time. The monitor also displays
Danger Nd-Yag laser
the number of mA circulating in the ring and the energy of
operation, either 1.5 or 1.3 GeV. Each day the ring must be
re-filled. At this time (approximately 3-5 times per day), the
display changes to the yellow graphic which models the
injection of electrons from the linac into the ring. Some
95% of all the radiation that is produced in the facility
occurs during the injection mode. Fortunately, injection
only takes about 1 minute. However, the display will
remain yellow until the electrons have been ramped from
200 MeV to the operating energy of at least 1.3 GeV.
Above the experimental hall door is a flashing red and
white sign which says. " Caution Radiation, Authorized
Personnel Only". This sign represents a terminal display of
our interlock system, such that the accelerators may not be
turned on unless this interlock system has been set. A
flashing sign here indicates that there is either potential for
beam in the machine or that there is beam in the machine.
To determine the status of the machine just turn to the
computer monitor to assess the situation.
The door also holds two signs: the international symbol for
radiation which must be visible when we are operating and
the danger Nd-Yag laser sign. The laser is located on the
experimental hall floor, 90o clockwise from the
experimental hall door behind some blue welding screen.
Because of the potential for serious eye injury, this area can
not be entered without proper eye protection. We bring it to
your attention for your own protection. Knowledge reduces
risk.
Highlights THE EXPERIMENTAL HALL
When you enter the experimental hall, you will observe
The Experimental that there is a utility distribution bridge. This is an eight-
Hall sided structure. In the middle of each of these spans is a
single red light. This is also a display of our interlock
system. When the light is illuminated, either beam is in the
Ring of Red Lights machine or the potential for beam exists. To confirm the
status of the beam, you may walk to any beamline which
houses an identical monitor to the one outside the
7 foot Shield Wall experimental hall door.
Use of ladders Additionally, there is a 7 foot concrete shield wall in the
experimental wall which houses the CAMD storage ring.
Obviously , one may not scale the shield wall nor can any
Announcements work above 7 feet in height be done in the CAMD
experimental hall during injection or stored beam. Thus, it
is clear that no ladders are permitted on the experimental
hall while the accelerator is in operation. Conversely, if a
ladder is brought into the experimental hall when the
accelerators are turned off, the person bringing the ladder
in is responsible for removing the ladder prior to operation
of the synchrotron .
Injection is preceded by a verbal announcement" Prepare
for injection" followed by the following: "Injection.
Injection, Injection". When injection is terminated you
will hear one of the following announcements: " Injection
is complete" or "Injection has been aborted due to a
technical failure, stand by for further instructions".
Radiation falls off as 1/distance squared increases as the
4th power of the energy
Highlights. RADIATION PRODUCTION AT CAMD
Whenever relativistic electrons are bent, usually by a magnetic
Radiation field, they produce the entire electromagnet spectrum, from infra-
Production red rays (long wave lengths) to X-rays. The CAMD synchrotron
light source (storage ring) is optimized for soft X-rays, up to 4
Synchrotron KeV. To achieve this goal, 8 magnets, each weighing 12 tons,
with a 45o bending radius are installed in the CAMD ring. It is
Light
Relativistic from each of these 1.7 Tesla magnets that synchrotron radiation is
Electrons given off tangentially. The normal operating energy is either 1.3
Threshold for GeV or 1.5 GeV. The CAMD electrons achieve speeds
Neutron approaching 99.9997% of the speed of light.
Production The threshold for neutron production is somewhere between 6 and
10 MeV, Normally the hardest X-ray coming down a beamline is
around 22 KeV at 1.5 GeV. When an insertion device is in
operation, this may increase to 60 KeV. Thus, any photons on the
Personnel experimental hall are below the energy threshold for neutron
Radiation production. However, inside the ring, it is possible to exceed this
Badges threshold. Neutrons are produced when electrons or photons hit
high Z materials such as lead, tungsten, or iron. These collisions
cause excess neutrons to be released from these heavy Z materials.
Monitoring at Eventually sufficient neutrons are removed so that the remaining
CAMD materials become unstable and remain radioactive (activated) even
after the storage ring energy has been removed. Activation is a
CAMD function of the energy of operation of the accelerators, the
Radiation efficiency of the machine during injection and the materials
Characterizat bombarded by the electrons and photons. For this reason,
ion: personnel dosimeters (badges) should be worn at all times when at
Prompt CAMD, especially if working in a front end or other work in the
Activation ring while the machine is turned off.
Everyone working at CAMD is provided with a personal
dosimeter or radiation badge. The badge is effective in recording
all exposures from photons. The badges are to be kept in your
assigned drawer at the CAMD facility when you are not wearing
it. You must wear your badge whenever you are at the CAMD
facility. Visitors staying less than one week do not normally
receive a "radiation badge". Users no longer receive a neutron
dosimeter since five years of monitoring showed no significant
exposure to neutrons in the experimental hall.
ALARA
Highlights CAMD subscribes to ALARA. ALARA is an
acronym which stands for "as low as reasonably
ALARA achievable". In practice, this means that CAMD
maintains an active and on-going radiation shielding
program such that radiation exposures are kept as
Alara low as is reasonably possible.
The ALARA is based on three guiding principles as
follows:
1) limit the time of exposure
2) maximize the distance from the source
3) use the appropriate kinds of shielding for the
radiation hazard at hand.
Basically, you are not permitted to set up camp at
CAMD. Theoretically, radiation falls off as 1/r2 or
one over the distance squared. In practice this
relationship appears to hold for distances > 100 feet
from the source. This is why the badge drawers are
located in the receiving area, or as far as is practical
from the storage ring source.
Radiation also varies to the 4th power of the energy.
Thus there is a slight increase in radiation when the
storage ring is operated at 1.5 GeV compared with
1.3 GeV. Nevertheless, shielding is adequate to
handle these differences.
The third principle of ALARA is to use the
appropriate kinds of shielding. For photons, lead
banding is placed in the short straight sections
through which the beamlines protrude. Additional
lead shielding is placed in and around the beamlines
at the levels of the shield wall. The shield wall is 7
feet high and varies in thickness form 2 to 3 feet. It is
reinforced with iron bars and is of a high density
containing several pebbles in the mixture. All these
things contribute to the overall effective photon
shield. However, the bound water in the concrete is
so effective against neutrons that neutron personnel
dosimeters have been discontinued.
Highlights Radiation Monitoring
Constant 24 hour a day monitoring of the facility is
Radiation accomplished using an ADM 610 ion chamber and
Monitoring a neutron detector. In addition, 25 places in the
facility are equipped with TLD's (thermoluminscent
Area Monitoring dosimeters) which are changed monthly. Other
TLD's are placed at the perimeter of the CAMD
Personal TLD's location. Weekly surveys are taken of both injection
and stored beam cycles. Surveys are also taken after
each shutdown or whenever there are significant
operational changes in the machine.
Wear your badge all the time you are at CAMD!
Badges must be kept in their assigned drawer when
not in use. There are three reasons for this.
1) The badge cabinet contains the badge controls.
2) We wish to evaluate only the CAMD portion of
your radiation exposure.
3) We change out the badges quarterly and must be
able to retrieve the badges.
Highlights RADIATION EXPOSURE UNITS
The roentgen is named after the discoverer of X-rays, Conrad
Radiation Roentgen. It is a unit of energy equivalent to 87.7 ergs per
gram. An erg is equivalent to 10-7 joules. However, this value
Exposure Units
is only appropriate for the study of X-rays or gamma rays in
Roentgen (R) = air.
87.7 ergs/gram. The Health Physicist is concerned with the amount of
radiation deposited in the body. This is the absorbed dose. In
rad (rad) = 100 the United States the rad is the term used to describe
ergs/gram absorbed radiation dose. It has a value of 100 ergs / gram (of
gray (Gy) = 1 J / material). Most of the rest world uses a value which is 100
Kg times larger than the rad. This is the Gray. It is abbreviated
Gy and is equivalent to 1 joule of energy deposited per
Roentgen kilogram mass.
equivalent man Since not all radiation is equivalent, quality factors assigned
(rem) = QF * rad to each type of radiation are used to give tissue equivalent
(rem). energy values. For instance the rad (100 ergs/gm) x the
Sievert (Sv) = QF) Quality Factor gives the Rem (roentgen equivalent man).
* Gy (Sv). Similarly the Gray (Gy at 1 joule of energy per kilogram) x
the quality factor gives a tissue equivalent value called the
Quality Factor Sievert (Sv). The Sievert is 100 times larger than the Rem.
(QF) Later we shall describe the significance of these quality
1 for gamma and X- factors.
rays.
2 for betas
2-10 for neutrons.
20 for alpha
particles.
Highlight
QUALITY FACTORS
s
Quality
Quality factors which are assigned to a packet of radiation are
Factors
determined by the biological effectiveness of a particle. For example,
a packet of radiation must have sufficient energy if it is to have an
effect on a liver cell of the body. This energy then is a function of the
LET
ability of the radiation to traverse the thickness of material to reach
the living cell in question. The energy lost over distance travelled is
Photons -
the linear energy transfer or LET. In other words, if one plots the
gamma
amount of energy deposited over distance traveled, you will obtain a
and X-
value from which the quality factor (or biological effectiveness) may
rays
be derived. This LET is related to the cross-sectional area available
for the interaction of radiation with materials, whether they be
Beta
biological or not. Photons are primarily wave-functions and therefore
Particles
have no mass. They can travel long distances in air without forfeiting
any energy. This is because they exhibit essentially no cross-sectional
Neutrons
area. Photons, like gamma and X-rays are assigned a quality factor of
1. Thus the rad and the rem are equivalent for photons. A beta particle
Alpha
is an electron ejected from the nucleus of an atom. An electron has a
Particles
mass of about 1/1840th the mass of a neutron. Still this mass
represents enough of a cross-sectional area, to give beta particles a
quality factor of 2. Thus electrons of equivalent energy to photons are
twice as damaging. Neutrons, which have a significant mass, are
assigned quality factors from 2-10 depending on their energy. 2-5
MeV neutrons are most damaging because they carry sufficient
energy to enter the body but do not have enough energy to travel
through the body. Thus, all the energy is trapped within the body. As
this energy is dissipated, cells are damaged by both direct and indirect
effects. Such neutrons are assigned a quality factor of 10. Alpha
particles are even more damaging. Their heavy mass (2 neutrons, 2
protons) provides a large cross-sectional area which results in their
being assigned a quality factor of 20.
RISK ASSESSMENT
Highlights The Linear No Threshold Model (LNTM) is a concept that suggests that
risk is directly proportional to dose. This model is derived from the high
Risk dose exposures of individuals present in Hiroshima or Nagasaki in 1945.
Assessmen There is no scientific basis for this model. On the other hand, there are
t no good studies for occupational radiation workers. Epidemiological
Linear No studies have only been extensively carried out for the survivors of
Threshold Hiroshima and Nagasaki.
Model Nevertheless, let us discuss two interesting studies. The Hanford study
Hanford reported on 37,000 occupational workers and 35,000 controls who were
Study followed for 30 years, or an average of about 1.5 generations. In
Chernobyl conclusion, the study found that the Hanford reactor workers had a
Study decreased incidence of cancer than did the control group. The study
Occupatio however, is not clear on how the controls were chosen, or if they
nal received equivalent preventative care.
Radiation The second study is the Chernobyl study which was published in 1996.
Workers It is a mathematical model predicting an increase in the incidence of
thyroid cancer in children and a concomitant rise in childhood leukemia
cases. The former observation has held true, but to date, the incidence of
childhood leukemia in children exposed to radiation as a result of the
Chernobyl disaster has not significantly increased. This suggests that
more work needs to be done to understand all of the complexities of
radiation exposure and the response of biological systems to such an
insult.
It is also obvious that there are few good epidemiological studies for
occupational radiation workers.
A Lawrence Berkeley Laboratory mathematical model has suggested
that an exposure of 1 Rem acutely (within an hour) would increase the
rate of fatal cancer in the United States from 1650 /10,000+/-40 to
1651/10,000 +/-40.
Let us put this into perspective for CAMD. The background radiation in
Baton Rouge is between 90 and 120 mrem per year. If you lived in
Denver, it would be about 360 mrem per annum. If one builds an X-ray
wing in a hospital, then one must shield the adjacent waiting area such
that someone occupying the space 24 hours per day 7 days per week and
365 days per year would not receive a dose of radiation in excess of 100
mRem per annum. Thus this is the public dose limit.
With respect to CAMD, no one has received a dose in excess of 30
mRem per year, or less than one third of the public dose limit. Even
though we are well below what is traditionally the public dose limit
where no badges are required, the state requires us to badge those
persons working at CAMD because we are radiation producing facility.
The occupational worker limit is 5000 mrem / year or 500 mrem/year for
a declared pregnant worker or an individual under the age of 18.
Highlights GENERAL SAFETY TIPS
The stairs to the Linac or Storage ring are very steep. Caution
General should be used when using this stairs which have a 30%
Safety Tips incline grade.
Stairs Fire extinguishers are located at every 65 feet on the outside
Fire perimeter of the experimental hall. Emergency plans are
Extinguishers posted at each beamline as well as in the cleanroom. All
Emergency CAMD telephones are equipped with a bright orange sticker
Plans displaying the emergency telephone numbers. Within the
experimental hall, exits are located at every 120o. Fire alarm
LSU Police
pull stations are also located at these doors. The fire alarm
system is connected to the LSU police via a keltron system. If
the emergency is not fire related, you may dial 911 to be
directly connected to the LSU police. They will address the
nature of the emergency and release the appropriate
emergency personnel
PERSONNEL SAFETY TIPS
Highlights
SAFETY DO'S Do's
AND DON'TS 1. DO READ AND OBEY SIGNS
2. WEAR BADGES WHILE AT CAMD
3. LEAVE BADGE IN DRAWER WHEN OFF-SITE
4. ASK IF UNSURE
5. VERIFY YOU HAVE THE CORRECT BADGE
6. REQUEST MSDS FOR ALL CHEMICALS
CHEMICALS AND INFORM CAMD SAFETY OF
THEIR USE.
Don'ts
1. DON'T CROSS BARRICADES
2. DON'T MOVE SHIELDING
3. DON'T MOVE MONITORING EQUIPMENT
4. DON'T LEND OR BORROW BADGE
5. DON'T ESCORT VISITORS WITHOUT
WEARING YOUR BADGE.
6. MOST IMPORTANTLY - DO NOT WORK
ALONE
7. NO CHEMICALS TO BE BROUGHT INTO CAMD
WITHOUT CAMD SAFETY APPROVAL
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