AN ABSTRACT OF THE THESIS OF
Alysse K. Bak for the degree of Masters of Science in Radiation Health Physics
presented on April 22, 2005.
Title: Assessing and Evaluating the Energy and Angular Dependence of the Selfindicating Instant Radiation Alert Dosimeter (SIRAD).
Abstract approved:
Redacted for Privacy
Kathryn A. Higley
The
Self-indicating
Instant
Radiation
Alert
Dosimeter,
SIRADTM,
manufactured by JP Labs*, is a dosimeter that can be used by emergency response
persoimel. It is a user-friendly, inexpensive, and disposable radiation dosimeter. It
monitors high doses, 5-200 rads, of ionizing radiation. The card resembles the size of a
credit card and is always active and ready to use. It can be worn around the neck like
an ID badge, or even placed in one's wallet. When the dosimeter is exposed to
radiation there is a permanent color change on the chemical sensing strip. This color
change is cumulative and proportional to dose.
The individual will be able to
immediately self-assess any dose to which they might be subjected.
SIRAD is
designed to provide the wearer and medical professionals instant, easy, and accurate
JP Labs., 120 Wood Avenue, Middlesex, NJ 08846, E-mail: sirad(a,jplabs.com, Internet:
www.j plabs.coni
on the radiation exposure of the victim. This will help assess the health risks and
guide in the treatment of the victim.
An evaluation of the cards to their response to gamma exposures between 2.5
and 125 rads was conducted. Cs-137, Ra-226, and Co-60 gamma sources were used to
measure this response. Angular dependence of the badges was also measured using
the Cs-137 and Ra-226 sources.
The badges were read and evaluated using a
commercially available flatbed scanner and Adobe Photoshop 7.O® software. The
device can also be read by personnel by using the color reference charts already built
into the device. Six doses; 2.5 rads, 5 rads, 7.5 rads, 10 rads, 40 rads, and 125 rads,
were tested. The results yielded a possibility of energy dependence but no angular
dependence for the Cs- 137 cards at a
150
angle and for the Ra-226 cards at a 45°.
©Copyright by Alysse K. Bak
April 22, 2005
All Rights Reserved
Assessing and Evaluating the Energy and Angular Dependence of the Self-indicating
Instant Radiation Alert Dosimeter (SIRAD)
by
AlysseK. Bak
A THESIS
submitted to
Oregon State University
in partial fulfillment of
the requirements for the
degree of
Master of Science
Presented April 22, 2005
Commencement June 2005
Master of Science thesis of Alysse K. Bak presented on April 22. 2005.
APPROVED:
Redacted for Privacy
Major Professor, representing Radiation Health Physics
Redacted for Privacy
the Department of'Nuclear Engineering and Radiation Health Physics
Redacted for Privacy
Dean of the th'aduate School
I understand that my thesis will become part of the permanent collection of Oregon
State University libraries. My signature below authorizes release of my thesis to any
reader upon request.
Redacted for Privacy
Alysse K. Bak, Author
ACKNOWLEDGEMENTS
I would like to express sincere appreciation and thanks to my advisor Dr.
Kathryn A. Higley for her support, encouragement, and guidance throughout my
graduate program. Coming into a new field she reminded me it would be similar to
learning a new language. She was right and taught me how to use everything around
me as my guidance and resources.
I thank Dr. David M. Hamby and Dr. Anna K. Harding for all their help and
support as well as for being on my committee. I would also like to thank Dr. Kenneth
S. Krane for being the Graduate Council Representative on my committee.
I would like to give special thanks to H. Michael Stewart for his assistance
with this project. I thank Dr. Scott Menn for his patience, time, and help with this
evaluation and Steve Smith for his technical help.
Finally, I would like to thank my parents, Elizabeth and Henry Bak, my
brother Michael Bak, and my dearest grandparents Louis and Mary Vetere, for all of
their love, support, and encouragement even though they are thousands of miles away.
This research was performed under appointment to the U.S. Department of
Energy Nuclear Engineering and Health Physics Fellowship Program sponsored by the
U.S. Department of Energy's Office of Nuclear Energy, Science, and Technology.
TABLE OF CONTENTS
1... INTRODUCTION
2
LITERATURE REVIEW
.
1
.
3
2.1
SIRAD ......................................................................................
2.2
DOSIMETERS USED BY EMERGENCY
RESPONSEPERSONNEL ...................................................... 8
3
2.2.1 Thermal Luminescent Dosimeter (TLD) ........................ 9
2.2.2 Electronic Dosimeters ..................................................... 10
2.2.3 Ionization Chambers ....................................................... 11
2.3
3
BIOLOGICAL RESPONSE (SYMPTOMS
TORADIATION ..................................................................... 12
MATERIALS .................................................................................... 14
3.1
SIRAD BADGES ..................................................................... 14
3.2
IRRADIATORS (RADIATION SOURCES) .......................... 14
3.3
VICTOREEN CONDENSER R-CHAMBER ....................... 16
3.4
EPSON PERFECTION 2480
3.5
ADOBE PHOTOSHOP 7.0® .................................................. 18
SCANNER ............... 17
4
METHODS ....................................................................................... 20
5
RESULTS ......................................................................................... 28
6
5.1
CONTROLCARDS ................................................................ 28
5.2
Cs-137 EXPOSURES .............................................................. 31
5.3
Ra-226 EXPOSURES .............................................................. 35
5.4
Co-60 EXPOSURES ................................................................ 38
DISCUSSION ................................................................................... 42
TABLE OF CONTENTS (Continued)
7
.42
6.1
CONTROLCARDS
6.2
Cs-137 EXPOSURES .............................................................. 42
6.3
Ra-226 EXPOSURES .............................................................. 43
6.4
Co-60 EXPOSURES ................................................................ 46
CONCLUSION ................................................................................. 48
BIBLIOGRAPHY ................................................................................... 49
APPENDICES........................................................................................ 51
APPENDIX A Control Card Picture and Graphs ............................. 52
APPENDIX B Cs-137 Pictures and Graphs ..................................... 54
APPENDIX C Ra-226 Pictures and Graphs ..................................... 62
APPENDIX D Co-60 Pictures and Graphs ....................................... 68
LIST OF FIGURES
Figure
2.1
A SIRAD badge prior to radiation exposure and
the black UV protective film for the SIRAD badge .......................... 4
2.2
Color bars taken from a SIRAD badge ............................................. 4
3.1
Cs-137 irradiator ............................................................................... 15
3.2
Gammacell 220 Co-60 irradiation unit ............................................. 15
3.3
Ra-226 needle .................................................................................... 15
3.4
Epson Perfection 2480
4.1
Set often SIRAD cards with a 150 angle
createdby a spacer ............................................................................ 22
4.2
Card set placed on the plexiglass over Well A
of the Cs-137 irradiator .................................................................... 23
4.3
Jig set-up on the Epson Perfection 2480
PHOTOTM scanner bed ...................................................................... 24
4.4
Histograms ........................................................................................ 25
4.5
SIRAD badge set at a 45° angle on the Ra-226 wheel ...................... 26
4.6
Ra-226 needle.................................................................................... 26
4.7
Gammacell 220 Co-60 irradiation unit .............................................. 27
5.1
Blank set control card from the Cs-137 2.5 rads set ......................... 28
5.2
Luminosity Calibration Curve........................................................... 29
5.3
Red Calibration Curve ........................................................................29
5.4
Green Calibration Curve ................................................................... 30
5.5
Blue Calibration Curve ..................................................................... 30
5.6
Cs-137 10 rads SIRAD badges ......................................................... 32
scanner ........................................ 18
LIST OF FIGURES (Continued)
Figure
Pag
5.7
Luminosity Values for Cs-137 and Calibration Curve ..................... 33
5.8
Red Values for Cs-137 and Calibration Curve ................................. 33
5.9
Green Values for Cs-137 and Calibration Curve .............................. 34
5.10
Blue Values for Cs-137 and Calibration Curve ................................ 34
5.11
Ra-226 2.5 rads SIRAD badges ........................................................ 35
5.12
Luminosity Values for Ra-226 and Calibration Curve ..................... 36
5.13
Red Values for Ra-226 and Calibration Curve ................................. 37
5.14
Green Values for Ra-226 and Calibration Curve .............................. 37
5.15
Blue Values for Ra-226 and Calibration Curve ................................ 38
5.16
Co-60 40 and 125 rads SIRAD badges ............................................. 39
5.17
Luminosity Values for Co-60 and Calibration Curve ....................... 40
5.18
Red Values for Co-60 and Calibration Curve ................................... 40
5.19
Green Values for Co-60 and Calibration Curve ................................ 41
5.20
Blue Values for Co-60 and Calibration Curve .................................. 41
LIST OF TABLES
Page
Table
4.1
Cs-137 irradiation times for SIRAD badges
4.2
Ra-226 irradiation times for SIRAD badges ..................................... 21
4.3
Co-60 irradiation times for SIRAD badges....................................... 21
5.1
Average of Control Card Intensity Values ........................................ 31
5.2
Averaged Color Readings for Cs-137 Irradiated Cards .................... 32
5.3
Averaged Color Readings for Ra-226 Irradiated Cards .................... 36
5.4
Averaged Color Readings for Co-60 Irradiated Cards ...................... 39
6.1
Gamma Ray Attenuation for selected Ra-226 progeny .................... 45
21
LIST OF APPENDIX FIGURES
Figure
ig
A-i
Blank set control card from the Cs-137 2.5 rads set ......................... 52
A-2
The Cs-137 set controls compared to the overall
controlcard at 0 rads ......................................................................... 52
A-3
The Ra-226 set controls compared to the overall
control card at 40 rads ....................................................................... 53
A-4
The Co-60 set controls compared to the overall
controlcard at 200 rads ..................................................................... 53
B-i
Cs-l372.SradsSlRADbadges ........................................................ 54
B-2
Cs-i 37 2.5 rads card set compared to the set control ........................ 55
B-3
Cs-137 2.5 rads set control graph ...................................................... 55
B-4
Cs-137 5 rads SIRAD badges ........................................................... 56
B-S
Cs-137 5 rads card set compared to the set control ........................... 56
B-6
Cs-137 7.5 rads SIRAD badges ........................................................ 57
B-7
Cs-137 7.5 rads card set compared to the set control ........................ 57
B-8
Cs-137 7.5 rads set control graph ...................................................... 58
B-9
Cs-137 10 rads SIRAD badges ......................................................... 58
B-iO
Cs-i37 10 rads card set compared to the set control ......................... 59
B-li Cs-i374oradsSiRADbadges ......................................................... 59
B-12
Cs-137 40 rads card set compared to the set control ......................... 60
B-i3
Cs-l37l25radsSIRADbadges ....................................................... 60
B-i4
Cs-i37 125 rads card set compared to the set control....................... 61
C-i
Ra-226 2.5 rads SIRAD badges ........................................................ 62
C-2
Ra-226 2.5 rads card set compared to the set control ....................... 63
LIST OF APPENDIX FIGURES (Continued)
Figure
C-3
Ra-226 2.5 rads set control graph ..................................................... 63
C-4
Ra-226 5 rads SIRAD badge ............................................................. 64
C-5
Ra-226 5 rads card set compared to the set control .......................... 64
C-6
Ra-226 7.5 rads SIRAD badges ........................................................ 65
C-7
Ra-226 7.5 rads card set compared to the set control ....................... 65
C-8
Ra-226 7.5 rads set control graph ..................................................... 66
C-9
Ra-226 10 rads SIRAD badges ......................................................... 66
C-i 0
Ra-226 10 rads card set compared to the set control ........................ 67
D-1
Co-60 40 rads SIRAD badge ............................................................. 68
D-2
Co-60 40 rads card set compared to the set control .......................... 69
D-3
Co-60 125 rads SIRAD badge, I ....................................................... 69
D-4
Co-60 125 rads card set compared to the set control, I ..................... 70
D-5
Co-60 125 rads card set compared to the set control
For 125 rads and 200 rads ................................................................. 70
D-6
Co-60 125 rads SIRAD badge, II ...................................................... 71
D-7
Co-60 125 rads card set compared to the set control, II .................... 71
ASSESSING AND EVALUATING THE ENERGY AND ANGULAR
DEPENDENCE OF THE SELF-INDICATING INSTANT RADIATION ALERT
DOSIMETER (SIRAD)
1. INTRODUCTION
Following the tragic events of September
there has been a fear instilled in
many people of the possibility of a nuclear terrorist attack which may include the use
of a "dirty bomb" or radiological dispersal device (RDD). In order to protect our first
responders from radiation exposure, there is a need for a durable device which can
quickly provide an indication of high radiation exposure. The Self-indicating Instant
Radiation Alert Dosimeter, SIRADTM, manufactured by JP Labs, is a dosimeter that is
targeted for use by emergency response personnel. It is used for the determination of
personnel exposure from radiation sources that a first responder may encounter during
a possible nuclear conflict or radiological accident. It is a user-friendly, inexpensive,
and disposable radiation dosimeter. It monitors high doses, 5-200 rads, of ionizing
radiation. When the badge is exposed to radiation, its chemical sensing strip will
change a shade of blue which will correspond to a dose on the adjacent color reference
chart. The card resembles the size of a credit card and is always active and ready to
use. It can be worn around the neck like an ID badge, or even placed in one's wallet.
The SIRAD dosimeter was put under an evaluation at Oregon State University
to determine its response to different gamma exposures as well as its angular
dependence. Angular dependence is important to test for because the wearer of the
SIRAD may be exposed from any angle.
Self-shielding or other factors may
contribute to erroneous readings. In-house irradiators were used to subject the badges
to pre-determined doses for evaluation.
The cards were evaluated with a
commercially available flatbed scanner and Adobe Photoshop 7.O® software. The
objective of this evaluation is to determine if the card meets the manufacturer claims
and to see if this is a reliable dosimeter for emergency response personnel to utilize.
The results will indicate if SIRAD works according to the SIRAD manual that can be
accessed through JP Labs.
2. LITERATURE REVIEW
2.1 SIRAD
The
Self-indicating
Instant
Radiation
Alert
Dosimeter,
SIRADTM,
manufactured by JP Labs, is a dosimeter that can be used by emergency response
personnel. It is a user-friendly, inexpensive, and disposable radiation dosimeter. It
monitors high doses, 5-200 rads, of ionizing radiation. The card resembles the size of
a credit card and is always active and ready to use. It can be worn around the neck
like an ID badge, or even placed in one's wallet. The dosimeter does not need a power
source. The sensing strip is protected by a black UV film. By lifting the film, the
sensing strip and the color reference chart can be easily viewed. The card is coated
with an anti-glare and scratch resistant film which protects the sensing strip and plastic
card. Figure 2.1 shows the SIRAD badge prior to exposure to radiation and the black
UV protective film which covers the badge.
4
W$ONJusEO5
0
!E9
0
CD
Ritn Airt flrimtpr
0
Keep this protective cover in place at all
ni0
times except when reading the badge. The
radiation sensing strip will change color on
prolonged exposure to ultraviolet light from
sunlight or fluorescent lights. This ensures
the maximum usable life of the sensor.
1
125
__
Evacus
-Do
e
1
- S
LNluuit I Il
*m
(1)
C,)
CD
0
d
*IpsI*ss
Figure 2.1 A SIRAD badge prior to radiation exposure (left) and the black UV
protective film for the SIRAD badge (right).
When SIRAD is subjected to radiation, the chemical sensing strip in the middle
of the card will change color. The strip will turn a shade of blue which can be
compared to one of the pre-pnnted color bars with a dose-number printed on either
side of the sensing strip. As the dose increases the intensity of the color blue will
deepen. The person wearing the dosimeter should be able to match the sensing strip to
one of the color bars to determine their dose.
0
5
10
25
40
75
125
Figure 2.2 Color bars taken from a SIRAD badge.
The sensing strip is composed of diacetylenes (R-C=C-C=C-R, where R is a
substituent group).
Diacetylenes are of a unique group of compounds and are
colorless solid monomers. When irradiated with high energy radiations such as X-ray,
gamma rays, electrons, and neutrons, they usually form red or blue-colored
polymers/plastics.
(JP Labs, 2005a)
The color of the
strip will intensify
proportionally to dose when it is irradiated. Low Cost (Casualty) Shelf Indicating
Dosimeter (LOCCSID) is another name often given to SIRAD tecimology.
According to manufacturer claims, the ability of the sensing strip to detect
radiation while it is shielded and exposed is discussed as follows. When the sensing
strip is unprotected, it is sensitive to all types of radiation that have energies higher
than approximately 10 eV. SIRAD has the potential to monitor X-rays (60 keV and
higher), high energy electrons and high energy beta particles. When the sensing strip
is covered with its black UV protective film it will absorb high LET (linear energy
transfer2)
particles of moderate (MeV) energies. Electrons greater than 1 MeV and
photons greater than 10 keV may be able to penetrate through the .01cm thick black
UV protective film and may be monitored by the sensing strip3. (JP Labs, 2005a)
SIRAD is a one-time use dosimeter with an expiration date (shelf-life). The
expiration date expresses the manufactures limited liability of the product. They claim
to have made reasonable efforts to make this product in its early stages free from
defects for a period of one year if it is used and stored properly. This expiration date
is dependent upon the dosimeter being stored at room temperature, < 25° C, and
protected from overexposure to ultraviolet and sunlight. If SIRAD is stored at higher
temperatures and/or unshielded from any ultraviolet and sunlight for extended
Linear energy transfer (LET) is the energy transferred per unit length of the track and is usually
express in keV/.tm. It should be noted that for a given type of charge particle, the higher the energy, the
lower the LET and therefore the lower its biologic effectiveness. High-LET particle include alphas,
betas (lower energy), protons, and neutrons. (Hall, 2000)
The manufacturers website states that "protons" can be monitored; as these are high LET particles
they would require energies >> MeV to penetrate the cover. Most likely this is a typographical error.
2
amounts of time, the strip may undergo polymerization resulting in a false positive
reading which can therefore reduce the shelf life of the dosimeter. An example of
overexposure to light is more than four hours of direct sunlight.
If the strip is
subjected to prolonged exposures of higher temperatures and/or ultraviolet/sunlight, a
false positive reading could result. The card is designed to be read under fluorescent
light. However, reading the strip numerous times under sunlight or normal ambient
light should have insignificant effects on the sensing strip. If the sensing strip is left
unprotected under direct exposures for a few weeks to ambient light, or one day to
diffused sunlight, a faint blue color will appear on the strip. JP Labs recommends
keeping the black film cover on all the time except for when reading the dosimeter and
to avoid exposures to high temperatures and UV/sunlight. They also recommend
adhering to the expiration date on the back of the card. (JP Labs, 2005b)
Other ambient conditions SIRAD may be exposed to are humidity, microwave
radiation, and accidental laundry cycles. JP Labs claims that the dosimeter will hold
up when subjected to such conditions. SJRAD is essentially unchanged by ambient or
high humidity. If the badge gets wet, it should be wiped dry. Since microwave
radiation is non-ionizing it will have no effect on the sensing strip; however a slight
heating effect may occur due to its plastic make-up. (JP Labs, 2005b) Even though
the badge will not be affected by being placed in a few normal laundry cycles of
washing and drying, it should be thrown out or returned.
SIRAD should not be
subjected to extended periods of exposure to temperatures higher than 900 C because
this may damage the sensing strip. In the event
SIRAD is
exposed to a fire, it will
burn and melt due to its plastic composition. (JP Labs, 2005b)
For emergency situations there is a need for a dosimeter that is instant, easy to
read, practically non-destructible, and monitors all types of radiation.
SIRAD's
description claims that it is designed with all of these properties and will be very
beneficially especially in a time when there is a high threat of radiological terrorism.
SIRAD may be used for determining personnel exposure from a radiation source that
one may encounter during a possible nuclear conflict or radiological accident. SIRAD
can be very valuable for first-responders to have because it gives an immediate
reading which might help prevent any additional exposure. This can also aid in the
assessment of the health risks and guide in treatment of a victim. (JP Labs, 2005d)
SIRAD has the potential to provide additional benefits to the wearer. It can
help assist the wearer of what actions he should or should not take. The sensing strip
will provide an early warning to leave the affected area and give an indication as to
what the wearer's level of radiation exposure is if it is less than 200 rads. The strain
on the healthcare system will be reduced because there will be no need to estimate
doses by other methods which may take several days.
SIRAD will
also help people
take preventive care and make affected people attentive of their increased risk of
cancer. (JP Labs, 2005e)
It is important to realize that SIRAD does not measure dose-rate. Because it is
an integrating, high-range device, it cannot detect dirty bombs, radiation sources,
radioactive material, and pre-irradiated material or people. The dosimeter will not
r]
monitor low doses (<1 rad) of radiation. The manufacturers state that the wearer
should be able to visually detect about 1-2% of the highest dose listed. For the 0-200
rads SIRAD, one may only see a shade of blue comparable to 2-4 rads. If using
spectroscopy or optical densitometry to read the chemical strip, color detection is
approximately 0.5-1% of the highest dose listed.
For this card the lowest dose
detectable is about 1-2 rads. It should only be used to measure the exposure to
radiation to which a person may be subjected to. (JPLabs, 2005f)
2.2 DOSIMETERS USED BY EMERGENCY RESPONSE PERSONNEL
Ionizing radiation is "any radiation displacing electrons from atoms or
molecules, thereby producing ions. Examples of ionizing radiation are alpha (a), beta
(Is),
and gamma (y) radiation and short-wave ultra-violet light. Ionizing radiation may
produce severe skin or tissue damage" (Hall, 2000, pg. 536). Since ionizing radiation
is known to cause cancer, it is important to monitor this type of radiation.
When it comes to monitoring radiation dose, SIRAD is a new device that is
good for first responders and those without a dosimetry program.
Other more
commonly used dosimeters by emergency response personnel are TLDs, electronic
dosimeters, and ionization chambers.
2.2.1 Thermo Luminescent Dosimeter (TLD)
Thermoluminescence occurs when a crystal emits light when it is heated after
being exposed to radiation. A TLD is based on of this effect. The absorption of
energy from ionizing radiation will excite atoms in a crystal which results in the
production of free electrons and holes in the thermoluminescent crystal. These in turn
are trapped by the activators or by imperfections within the crystalline lattice which
traps the excitation energy in the crystal. The heating of the crystal releases the
excitation energy as light. A glow curve is created by the heating of the irradiated
crystal at a uniform rate and measures the emitted light as the temperature increases.
The light output is directly proportional to the amount of thermoluminescent material
and to the dose received. There are several formulations of compounds that are used
as TLDs. Common ones include LiF, CaF2:Dy, CaSO4, and many others. Each has
unique sensitivities and fading characteristics. (Cember, 1996, pg. 369)
TLDs are used as personal and environmental integrating dosimeters. After
being worn for a designated period of time, the TLD is analyzed, typically by being
sent to an analytical laboratory. The badge can only be read once during processing
and are essentially "reset" by the effort. TLDs are beneficial to wear because they can
monitor low doses of radiation (0.00 1 rad) and are independent of dose rate. The
badge has the capabilities of being recycled for multiple uses and is inexpensive. It is
small and light weight so it will not interfere with a person's task in an emergency
situation. TLDs often lack uniformity in response and batch calibration is needed.
10
The TLD can also undergo fading and can be light sensitive. No permanent record is
retained within the TLD. TLDs have supplanted film badges as the preferred method
for monitoring personnel exposure. This is primarily due to cost.
2.2.2 Electronic Dosimeters
Electronic dosimeters are a combination of the constant progression of solid-
state electronics and electronic data processing. They come in many shapes, sizes,
weights, and capabilities. Accurate electronic dosimeters have been referred to as
being more useful for personal dosimetry and dose tracking than a TLD. They have
the capability to display instantaneous dose rate and can integrate over time to display
cumulative dose. Several electronic dosimeters are equipped with built in alarms.
Many electronic type dosimeters are being used by emergency response
personnel because they are easy to use and no experience or knowledge about how
they work is needed. Many electronic dosimeters have the capability to transfer data
to a computer. Electronic dosimeters also require the use of a power source. They can
be specifically designed to suit specific needs, i.e., firefighters in extreme heat.
However, they can be expensive, bulky, and fragile at times depending on its
application.
Examples of electronic dosimeters are: electronic personal dosimeters
which resemble a pager and have the ability to detect beta and gamma radiation over a
wide range of dose rates and doses; Canberra's Mini-Radiac Personal Radiation
Monitor which is designed for the needs of first responders and is gamma energy
11
dependent at +1- 20% 80 keV to 3 MeV; and the Canberra D1NEUTRON which is a
portable unit for neutron dosimetry and works within an energy range of 0.025 eV to
15 MeV.
2.2.3 Ionization Chambers
Ionization chambers are used for its capabilities of measuring gamma-ray
exposure and beta dose rates with corrections.
They have responses that are
proportional to absorbed energy and are used to make dose measurements. Most
ionization chambers have an air-equivalent wall and measure exposure as opposed to
dose. Ionization chambers are typically not very sensitive, and consequently are not
for detecting contamination. They are more often used for assessing exposure or dose.
These instruments are also known for their fragility and for being expensive.
The portable ion chamber comes in many different designs.
They are
commonly used as survey meters for radiation monitoring. An ion chamber consists
of "a closed air volume of several hundred cm3 from which the saturated ion current is
measured using a battery-powered electrometer circuit" (Knoll, 2000, pg. 145). The
walls of the chamber are just about air equivalent. The ion chambers yield fairly
accurate measurements of the exposure for gamma-ray energies. The measurements
of the reading are just high enough and just low enough to avoid considerable
attenuation in the walls or entrance window and to create electronic equilibrium in the
walls, respectively. There are other types of portable ion chambers that are used for
12
dose measurements.
These are based on the charge integration principle.
The
chamber is usually charged and placed in a radiation field for a period of time. The
drop in the voltage is then used as a measure of the total integrated ionization charge.
(Knoll, 2000)
2.3 BIOLOGICAL RESPONSE (SYMPTOMS) TO RADIATION
Acute whole-body irradiation can occur if one is exposed to a situation
including ionizing radiation. Early radiation lethality is usually death occurring within
a few weeks of an exposure to a specific high-intensity exposure to radiation. Soon
after exposure, symptoms will appear for a limited period of time known as the
prodromal radiation syndrome. The symptoms in this syndrome will vary.
They
usually depend on the time of onset, maximum severity, and duration depending on
the size of the dose. Two main groups of this syndrome are gastrointestinal (nausea,
vomiting, diarrhea etc.) and neuromuscular (fatigue, apathy, sweating, fever,
headache). All symptoms will not be evident unless the dose is> 10 Gy (1000 rad),
which is considered supralethal.
Receiving a supralethal dose will likely cause
neuromuscular symptoms and likely death. Those receiving a dose of 4 Gy (400 rad)
will experience gastrointestinal symptoms with possible recovery. (Hall, 2000)
When exposed to a whole-body dose of 2 Gy (200 rad) the hematopoietic
syndrome appears. At this dose, blood forming organs (bone marrow) are the most
sensitive.
This causes cell populations to be significantly reduced and the
13
repopulation of mature functioning blood cells is hindered. The loss of mature blood
cells can lead to anemia and an increased risk of infection.
Symptoms of this
syndrome include malaise, fatigue, and epilation. Death can occur within a few
months due to the damage done to the bone marrow or infection. (Hall, 2000)
The gastrointestinal syndrome will develop at exposures of .10 Gy (1000 rad).
The intestinal epithelium is destroyed and there is almost complete destruction of bone
marrow. All effects of the hematopoietic syndrome occur. Other symptoms present in
this kind of exposure include severe nausea, vomiting and explosive diarrhea. Death
will likely occur within several weeks. (Hall, 2000)
The last syndrome to occur is the cerebrovascular syndrome which is present at
exposures > 20 Gy (2000 rad). Severe damage is done to the central nervous system
(CNS) and other organ systems. Symptoms include all hematopoietic and
gastrointestinal syndrome symptoms as well as unconsciousness within minutes.
Death is certain within hours or days depending on the magnitude of the dose. (Hall,
2000)
14
3. MATERIALS
3.1 SIRAD BADGES
The SIRAD with a 0-200 rad color reference chart was evaluated. The card's
features and abilities have already been discussed in section 2.1.
3.2 IRRADIATORS (RADIATION SOURCES)
Oregon State University's Radiation Center sources were used to irradiate the
cards: a Cs-137 irradiator, the Gammacell 220 Co-60 irradiation unit, and a Ra-226
needle. The Cs-137 irradiator has an 8 Ci source and was assayed on June 8, 2004g.
Cesium 137 has a half life of 30.07 years and undergoes radioactive decay, emitting a
beta particle and a 0.662 MeV gamma. (EPA, 2005a) The Gammacell 220 Co-60
irradiation unit delivers an exposure
rate5
of 8.38E+4 R h'. The Co-60 source was
1022.6 11 Ci on March 5, 2005. Co-60 undergoes radioactive decay and emits beta
particles as well as two gamma rays at 1.173 MeV and 1.332 MeV (EPA, 2005b) The
half life of Co-60 is 5.27 1 years. The Ra-226 needle is a pedigreed, traceable, 10 mCi
source with an exposure rate of 94.1 mR
h1
at one foot as of February 1, 2005.
(Union Miniere, 1974) Radium 226 is found in the U-238 decay series. It emits two
Radiation Center Health Physics Procedure 18, Revision #8, Oct. 2004
Radiation Center Health Physics Procedure 21, Revision #5, Feb. 2000
15
aiphas with energies of 4.784 MeV and 4.602 MeV as well as a .186 MeV gamma. It
has a half life of 1599 years. (EPA, 2005c)
Figure 3.1 Cs-137 irradiator. Well A (Large Source) at 10.5 in. over plexiglass
shield is shown on the left. The Cs- 137 irradiator odometer and control box are
shown on the right.
Figure 3.2 Gammacell 220 Co-60
irradiation unit.
Figure 3.3 Ra-226 needle.
16
3.3 VICTOREEN CONDENSER R-METER
Two Victoreen Condenser RMeters* were used to help determine the traveling
dose within the chamber of the Co-60 irradiator. The traveling dose is the amount of
dose the cards will receive in the time it takes for them to move from their starting
point at the top of the sample chamber down the column to the source assembly and
back up. The Victoreen Condenser R-Meter is an instrument that yields quick and
accurate measurements of total-X-ray exposure in roentgens. It is a.c. operated and
may be used with a suitable timing device to determine average X-ray intensity. It has
a dust-tight electrometer with a viewing microscope system, a lighting system for the
microscope, an onloff light, and necessary operating controls. The Condenser RMeter is used with interchangeable ionization chambers. The ionization chamber is
sensitive to X-ray radiation in the normal X-ray therapy ranges. Thick wall chambers
can be used to receive accurate measurements of high energy radiation, i.e. Co-60 and
Radium sources.
(Victoreen6)
The ionization chamber is charged by the charger-electrometer unit of the
Condenser R-Meter to a predetermined voltage. When the active volume (ionization
chamber) is placed in an X-ray field, the air within the ionization chamber is ionized
in proportion to the X-ray intensity. The ions will attract to oppositely charged
electrodes within the chamber. This ion migration reduces the charge of the capacitor.
The Victoreen Condenser R Meters are not certified.
The Victoreen Instrument Company, 10101 Woodland Avenue, Cleveland, Ohio 44104. "Instruction
Manual Condenser R-Meter
6
17
As a result, the potential difference across its electrodes is reduced. The scale reading
for this potential is equivalent to the X-ray exposure of the chamber. The exposure is
read in roentgens. (Victoreen)
3.4 EPSON PERFECTION 2480 PHOTOTM SCANNER
An Epson Perfection 2480 PHOTOTM scanner was used to capture images. It
is a flatbed color image scanner with a Color Epson
MatrixCDTM line sensor.
It
reaches an optical resolution of 2400 dpi. The scanner has a color hardware bit depth
of 48-bits per pixel internal, 48-bits per pixel external and a grayscale hardware bit
depth of 16-bits per pixel internal and 16-bits per pixel external. Depending on the
image editing software, external bit depth is selectable to 16 bits. The scanners optical
density is 3.2 Dmax. (Epson, 2005)
The Epson Perfection 2480 PHOTOTM scanner has a start, copy, scan to Email, Scan and Save buttons. It is 10.83in wide, 16.5in deep, 3.4in high, and weighs
6lbs. Its maximum read area is 8.5" x 11.7" (21.6cm x 29.7cm). A white cold cathode
fluorescent lamp is its light source. A Hi-Speed USB 2.0 is the necessary interface for
the printer. The scanner operates on a 2400 dpi high-speed mode. It is reliable up to a
MCBF
10,000 cycles. The scanner is compatible with most Windows programs
containing Pentium®II or higher and iMac® or any G3 or later with built-in USB.
(Epson, 2005)
18
Figure 3.4 Epson Perfection 2480 PHOTOTM scanner.
3.5 ADOBE PHOTOSHOP 7.O®
Adobe Photoshop 7.0® software was used in conjunction with the Epson
scanner to read and evaluate the badges. The software contains a File Browser which
allows you to search for images visually instead of by file name. The software has a
histogram feature which displays the luminosity, red, green, and blue distributions and
values for a picture.
It also calculates the standard deviation for each graph.
Information on how the program calculates the standard deviation has not been found.
It is not in the literature and calls to Adobe technical support and headquarters have
not been successful. Two ways in which the standard deviation may be calculated are
by Full Width at Half Maximum or by summing the square difference of the points on
a graph.
Photoshop requires Intel Pentium II or better, 128 MB of RAM, 280 MB of
available hard disk space, a color monitor with a 16-bit color or greater video card,
19
800 x 600 or greater monitor resolution, and a CD-ROM drive. It is also compatible
with most Windows programs. (EBay, 2005)
20
4. METHODS
Two hundred SIRAD badges were provided to Oregon State University by
Todd Brethauer, Technical Support Working Group (TSWG) Science Advisor at the
US Department of Defense located in Washington, D.C. The following doses where
chosen for evaluation: 2.5 rads, 5 rads, 7.5 rads, 10 rads, 40 rads, and 125 rads. Ten
cards were irradiated at each dose with each group having its own control card. One
card was kept as an overall control for comparison. A control card and a set control is
a card that was not subjected to any radiation, kept at room temperature, and protected
from ultraviolet/sunlight. There is no physical difference between the two types of
control cards. All six doses were tested using the Cs-137 irradiator. The Ra-226
needle only irradiated the 2.5 rad, 5 rad, 7.5 rad, and 10 rad card sets and only 40 rads
and 125 rads were tested with the Co-60 irradiator.
Time for irradiation using the Cs-137 irradiator, Co-60 irradiation unit and the
Ra-226 needle were calculated by using the exposure rates for each source and the
known doses. A conversion factor was not needed because "an exposure of 1 roentgen
is frequently considered approximately equivalent to an absorbed dose of 1 rad"
(Cember, 1996, pg. 178).
Time =
Dose
ExposureR ate
Equation 4.1
21
The times were then converted into the proper time units needed for each irradiator.
Table 4.1 Cs-137 irradiation times for SIRAD badges.
Cs-I 37 Irradiation Times
Rate
(mR/h)
5780
5780
5780
5780
5780
5780
mRad
2500
5000
7500
10000
40000
125000
Time (h)
0.43
0.87
1.30
1.73
6.92
21.63
Time
(mm)
25.95
51.90
77.85
103.81
415.22
1297.58
Table 4.2 Ra-226 irradiation times for SIRAD badges.
Ra-226 Irradiation Times
mRad
2500
5000
7500
10000
Rate
(mR/h)
94.1
94.1
94.1
94.1
Time
(sec)
95642.93
191285.9
286928.8
382571.7
Table 4.3 Co-60 irradiation times for SIRAD badges.
Co-60 Irradiation Times
Dose
(Rad)
40
125
Exposure Rate
(R/h)
8.38E+04
8.38E+04
Time
(sec)
1.72E+00
5.37E+00
The Cs-137 series was used to represent a mid-range gamma energy exposure.
The badges were exposed to all six doses. Each irradiation was configured by having
a card set of 10 cards taped together in a small stack. Using a spacer and tape, card
number ten was raised to a 150 angle. The angle was calculated the following way:
22
I
Not drawn
to scale.
_içTIIIIIl
A 8.5cm
8 = arctan
8 = arctan
A
2.3cm
8.5cm
8 = 15
°
Equation 4.2 Angle determination for the Cs-137 series.
The adjacent side, A, is the length of the SIRAD card and the opposite side, 0, is the
height of the spacer.
Figure 4.1. Set often SIRAD cards
with a 15° angle created by a spacer.
In order to receive the proper doses, the settings for the Cs- 137 irradiator were
taken from Radiation Center Health Physics Procedure (RCHPP) 18 table 3: The
Decay Corrected Exposure Rates and Odometer Settings for Wells A and B at 10.5 in.
23
and 2.5 in. above the Wells. Following Well A, large source information for the first
half of 2005, the head Health Physicist (HP) of Oregon State University's Department
of Nuclear Engineering and Radiation Health Physics set the odometer at 192.2 and
the plexiglass shield at 10.5 in. With guidance from the head HP, the set of cards were
placed on the plexiglass shield with card number ten on the top. Each card set was
irradiated for the appropriate amount of time.
Figure 4.2 Card set placed on the plexiglass over Well
A of the Cs-137 irradiator.
Each card was labeled with isotope, date irradiated, card number, and dose
received. As mentioned earlier, each set of cards has its own control card. Each card
was scanned individually and all cards were placed in the same area of the scanner.
The scanner was set at a dpi of 1200. This resolution was chosen because of its
quality and speed. Figure 4.3 shows a jig that was set up on the scanner to ensure that
24
all of the cards were placed in the same spot to help deter any variance in the card
readings.
Figure 4.3 Jig set-up on the Epson Perfection 2480 PHOTOTM
scanner bed.
Once the card was scanned it was saved and opened in the Adobe Photoshop
7.O® application. Using this software, the portion of the card being evaluated was
highlighted and a histogram was created. The histogram provided intensity readings
for luminosity, red, green, and blue. It also provided the standard deviation for each
read ing.*
Figure 4.4 is an example of what the luminosity, red, green, and blue
histograms look like.
The standard deviation for 2.5 rads and 7.5 rads card sets was calculated by taking the average of the 0
and 5 rads color chart readings and the 5 and 10 rads color chart readings, respectively. This is based
on the assumption of linearity between these points on a graph. The numbers for luminosity, red, green,
and blue were calculated from equations resulting from set control graphs.
25
Charnel:
I.r1e.r
I
k.
Mean 10603
Std Dev 1603
Level
Percentile.
Pixels: 77070
CaChe Level:
I
Chanrl: Iei
Mean
Count:
Median. 104
OK
1
.35
Level
Std Dev 23.82
Median: 78
Pixels: 77070
Count
PercentIle:
CaChe Level:
1
I1bwInli
Channel
&eerI
Mean: 104.90
StdDev:22,50
Median: 1C
Pixels: 77070
Charnel
A
Level:
Ccxjit:
PerCentlix:
CaChe Level: I
Blue
Meat: 182.13
StdDev: 1223
Median: 183
Pixels 77070
level:
Cwit.
PercentIle.
CacheLevel. I
Figure 4.4 Histograms. The luminosity, red, green, and blue histograms for 75
rads on the SIRAD overall control color chart created by Adobe Photoshop 7.O®.
The numbers were recorded, entered into Microsoft Excel®, and graphed. The
graphs display the intensity values for each card and the set control with error bar
values taken from the histograms. These graphs can be seen in Appendix A-D. For
the control card and each set control card, the entire color reference chart and the
sensing strip were read. All irradiated cards had only their sensing strip read. Each
set's control card was compared to the overall control. Each color on the color chart
and the strip was individually read and compared.
The Ra-226 needle was used to irradiate badges at 2.5 rads, 5 rads, 7.5 rads,
and 10 rads. Angular dependence was also tested. Since the Ra-226 needle is an
isotropic source, it is placed in the center of a rotating wheel.
Each card was
individually attached to a holder and placed within a slot exactly one foot from the
26
source. Card number ten was used to test for angular dependence at
45°.
Since the
cards were not stacked like those in the Cs-137 sets, the angle was measured a
different way. An inch was measure and marked in two directions and then the card
was place against a peg creating a 45° angle. The cards were read and evaluated in the
same manner as those in the Cs-137 series.
Figure 4.5 SIRAD badge set at a 45° angle
on the Ra-226 wheel. Not drawn to scale.
Figure 4.6 Ra-226 needle. SIRAD badges are attached to holders and inserted
into slots on the wheel one foot from the source.
27
The Gamniacell 220 Co-60 irradiation unit was used to irradiate doses of 40
rads and 125 rads. The cards were taped ten together with no angular dependence
being tested for card number ten. They were placed in a beaker. The beaker was then
placed inside the chamber of the irradiator. The irradiation times for each dose were
double checked by the head HP with a computer program designed especially for the
Co-60 irradiator. A Victoreen Condenser R-Meter was placed inside the chamber to
check for traveling dose. The cards were not present in the chamber during traveling
dose runs. The traveling dose was tested a total of six times, three for each R-Meter.
These cards were also read in the same manner as the Cs-137 and Ra-226 series.
Figure 4.7 Gammacell 220 Co-60 irradiation unit.
5. RESULTS
5.1 CONTROL CARDS
The overall control card was used as reference for the set control cards. The
overall control card and the set control cards are blank cards not subjected to any
radiation.
Each dose from the color reference chart on all the controls was read,
charted, and graphed. A histogram was created to compare each set control in each
series with the overall control. There was slight or no variation among the cards and
they were statistically similar to the overall control. Examples of these graphs can be
found in Appendix A. There were a total of 12 set control cards and one overall
control card. The intensity values for each card were averaged and plotted on a semilog graph to form a calibration curve with error bars at two standard deviations. These
graphs can be seen in figures 5.2 -5.5.
0
&#tRadbon..
Hazard 5-:
L..J
Warning 10
EXPSONJU#4f3S,2IS5
40
75
125
Evacuate 25
Protsd Rad4aon Sensing 3flp *vm prolongsd
exporsem UV/su$lgM & high tsmpe.jrss
Figure 5.1 Blank set control card from the Cs-137 2.5 rads set.
29
Luminosity Calibration Curve
250
200
10
25
150
40
c
LuminoyJ
100
125
50
200
0
1
1000
100
10
Dose (Rads) on Color Reference Chart
Figure 5.2 Luminosity Calibration Curve. Each point represents the average
values of each dose on the color reference charts for all of the control cards in the
evaluation. Error bars were calculated to two standard deviations.
Red Calibration Curve
250
200
110
150
-I-
125
100
j40
1
1125
50
j 200
0
1
10
100
1000
Dose (Rads) on Reference Color Chart
Figure 5.3 Red Calibration Curve. Each point represents the average values of
each dose on the color reference charts for all of the control cards in the
evaluation. Error bars were calculated to two standard deviations.
Ii
Green Calibration Curve
250
200
I10
rT
---
150
40
0
100
-1-75
125
50
! 200
0
100
10
1
1000
Dose (Rads) on Reference Color Chart
Figure 5.4 Green Calibration Curve. Each point represents the average values of
each dose on the color reference charts for all of the control cards in the
evaluation. Error bars were calculated to two standard deviations.
Blue Calibration Curve
250
Io
200
25
r40
100 --
! 125
150
!200
50
0
100
10
1
1000
Dose (Rads) on Reference Chart
Figure
5.5
Blue Calibration Curve. Each point represents the average values of
each dose on the color reference charts for all of the control cards in the
evaluation. Error bars were calculated to two standard deviations.
31
Table 5.1 Average of Control Card Intensity Values
Parameter
Measured
Luminosity
Red
Green
Blue
Average of Control Card Intensity Values, n = 12
Color Key Listed Dose (rads)
0
5
10
227.67
227.71
231.63
206.67
204.86
192.13
210.62
208.66
185.30
167.09
191.59
201.24
25
151.83
123.15
155.71
209.25
40
135.60
103.31
139.49
202.81
75
102.08
74.07
101.60
181.08
49.26
66.55
160.75
200
45.98
22.11
39.49
145.95
10.04
3.94
3.57
200
3.32
5.85
2.74
4.02
125
71.76
Standard_Deviation of Average Control Card Intensity Values
Parameter
75
125
Measured
10
25
40
0
5
8.17
10.80
8.014
7.71
Luminosity
5.35
6.68
5.39
Red
Green
Blue
7.21
4.86
4.23
9.83
7.56
7.59
13.47
9.79
9.36
12.24
11.91
7.21
2.91
7.00
2.34
11.28
5.54
1.12
5.2 Cs-137 EXPOSURES
All six doses were evaluated in the Cs-137 series. The values for each card
were charted and graphed. All ten cards in the set were compared to each other as
well as the set control in a bar graph. Error bar values were taken from the Adobe
Photoshop 7.0® histograms. These graphs can be seen in Appendix B. Card number
ten was used to test for angular dependence (AD) at 150. Intensity values for cards
one through ten in each set were averaged for each dose and plotted on the calibration
curve for comparison. The error bars were calculated to two standard deviations.
Card number one and number ten for 10 rads is displayed to show the similarity in
their dose and color.
32
EXPRE5OWJUNE*2OO5
0
i
0
Rsdsflon
4S,._JHSZ$fd5
Hazavd
EXPIRES ON JUNE 30, 2005
40
75
Warning 10
125
Evacuae25
.
,
i) Pmlsd Radr Sunsng Sp from pmlonged
Protsd Radlaflon S.nsmg S1p from mong
SXpOaUf$aIQ LNMUni&
exposurss
UV
& nigh srnp&*ims
Figure 5.6 Cs-137 10 rads SIRAD badges. SIRAD badge number one irradiated
to 10 rads by the Cs-137 irradiator (left) and SIRAD badge number 10 irradiated
to 10 rads by the Cs-137 irradiator (right) are shown side by side to show the
uniformity of the color on the sensing strips. Card number 10 was placed at a 15
angle to test for angular dependence.
Table 5.2 Average Color Readings for Cs-137 Irradiated Cards
Averaged Color Readings for Cs-137 Irradiated Cards, n = 10 per dose
Dose delivered to cards (rad)
Parameter
Measured
2.5
5
7.5
10
40
125
Luminosity
Red
Green
Blue
211.19
200.58
216.741
210.295
2.252269
3.073844
1.887396
3.015416
195.799
202.443
210.519
186.442
164.562
192.734
212.352
178.25
154.29
184.585
209.625
119.168
94.425
118.708
189.168
53.691
154.312
3.259631
4.132946
3.186137
2.028825
2.531803
3.103429
2.118473
10.52353
4.010719
4.650047
4.256313
2.432726
3.870123
3.882797
4.919926
2.845391
7.297107
3.935457
9.331073
6.151486
177.31
66.259
58.69
Standard Deviations of the Averaged Color Readings for Cs-I 37 Irradiated
Cards
Parameter
Measured
2.5
5
7.5
10
40
125
Luminosity
Red
Green
Blue
33
Luminosity Values for Cs-137 and Calibration Curve
250
'2.5
200
tb
'
25
150
LLJ
Luminosit
40
-
100
----------
75
1125
50
0
1000
100
10
1
Dose (Rads) on Color Reference Chart
Figure 5.7 Luminosity Values for Cs-137 and Calibration Curve. Each gray
point represents the average values of each dose on the color reference charts for
all of the control cards in the evaluation. Each black point represents the
average value for all ten cards at each dose irradiated in the Cs-137 irradiator.
Error bars were calculated to two standard deviations.
Red Values for Cs-I 37 and Calibration Curve
250
-2-5------------------
200
!:
150
T
_10
-
--7-5
100 ------------------------------50
--
j25
-
L
[CS.1371
40
-
125
-
200
0
1
10
100
1000
Dose (Rads) on Color Reference Chart
Figure 5.8 Red Values for Cs-137 and Calibration Curve. Each red point
represents the average values of each dose on the color reference charts for all of
the control cards in the evaluation. Each black point represents the average
value for all ten cards at each dose irradiated in the Cs-137 irradiator. Error
bars were calculated to two standard deviations.
34
Green Values for Cs-I 37 and Calibration Curve
250-j
'25
200
£
110
25
150
Green
40
Cs-i 37
100
1-75-
125
50
! 200
010
100
Dose (Rads) for Color Reference Chart
Figure 5.9 Green Values for Cs-137 and Calibration Curve. Each green point
represents the average values of each dose on the color reference charts for all of
the control cards in the evaluation. Each black point represents the average
value for all ten cards at each dose irradiated in the Cs-137 irradiator. Error
bars were calculated to two standard deviations.
Blues Values for Cs.137 and Calibration Curve
:::i
!25
___5
40
75
125
200
Cs-i 37
11501
100
0
1
10
100
1000
Dose (Rads) on Color Reference Chart
Figure 5.10 Blue Values for Cs-137 and Calibration Curve. Each blue point
represents the average values of each dose on the color reference charts for all of
the control cards in the evaluation. Each black point represents the average
value for all ten cards at each dose irradiated in the Cs-137 irradiator. Error
bars were calculated to two standard deviations.
35
5.3 Ra-226 EXPOSURES
The SIRAD cards in the Ra-226 series were subjected to 2.5 rads, 5 rads, 7.5
rads, and 10 rads. The values for each card were charted and graphed. All ten cards in
the set were compared to each other as well as the set control in a bar graph. Error bar
values were taken from the Adobe Photoshop 7.0® histograms. These graphs can be
seen in Appendix C. Card number ten was used to test for angular dependence (AD)
at 45°. Intensity values for cards one through ten in each set were averaged for each
dose and plotted on the calibration curve for comparison.
The error bars were
calculated to two standard deviations. Card number one and number ten for 2.5 rads is
displayed to show the similarity in their dose and color.
0 wS ON Jul11 * a*
75
I
125
Evucusis
-
.9
0 V1 Oil JUl11 IS, ISSI
-
W"j)
W$
Figure 5.11 Ra-226 2.5 rads SIRAD badges.
d
Ci)
Pvald Ro S.nN Ib
from juL..d
AimWig 10
_75
26
Evscusls
Pvd Rathallon S.rsng Sp from pwb..d
.xposu LN1UrI & h l.mpsMxss
SIRAD badge number one
irradiated to 2.5 rads by the Ra-226 needle (left) and SIRAD badge number 10
irradiated to 2.5 rads by the Ra-226 needle (right) are shown side by side to show
the uniformity of the color on the sensing strips. Card number 10 was placed at a
45° angle to test for angular dependence.
36
Table 5.3 Averaged Color Readings for Ra-226
Irradiated Cards
Averaged Color Readings for Ra-226 Irradiated Cards,
n = 10 per dose
Parameter
Measured
Dose delivered to cards (rad)
2.5
203.202
187.275
Luminosity
209.566
212.47
2.435402
2.742023
2.59689
2.14886
3.05697
3.667152
3.247624
2.97637
Red
Green
Blue
7.5
173.731
5
184.78
162.843
191.239
209.945
10
149.178
179.455
209.985
162.174
136.128
167.079
206.93
Standard Deviations of the Averaged Color Readings
for Ra-226 Irradiated Cards
Parameter
Measured
2.5
5
7.5
10
Luminosity
Red
Green
Blue
2.040925
2.446509
3.185037
3.404739
3.364646
2.463277
2.2481 05
1.815128
Luminosity Values for Ra-226 and Calibration Curve
L2.5
200
.
10
,150C
-25
'40
0
C
Ra-226
.7
100
125
50
200
0I
1
10
100
1000
Dose (Rads) on Color Reference Chart
Figure 5.12 Luminosity Values for Ra-226 and Calibration Curve. Each gray
point represents the average values of each dose on the color reference charts for
all of the control cards in the evaluation. Each black point represents the
average value for all ten cards at each dose irradiated in the Ra-226 irradiator.
Error bars were calculated to two standard deviations.
37
Red Values for Ra-226 and Calilbratin Curve
250
200
r25
150
7.5
!
110
Li
ed
25
100
f
1
50
1125
0
200
100
10
1
1000
Dose (Rads) on Color Reference Chart
I
Figure 5.13 Red Values for Ra-226 and Calibration Curve.
Each red point
represents the average values of each dose on the color reference charts for all of
the control cards in the evaluation. Each black point represents the average
value for all ten cards at each dose irradiated in the Ra-226 irradiator. Error
bars were calculated to two standard deviations.
Green Values for Ra-226 and Control
250
5
200
j25
150
40
100
I
Ra-226
75
4 125
50
tI
200
0
1
10
100
1000
Dose (Rads) on Color Reference Chart
Figure 5.14 Green Values for Ra-226 and Calibration Curve. Each green point
represents the average values of each dose on the color reference charts for all of
the control cards in the evaluation. Each black point represents the average
value for all ten cards at each dose irradiated in the Ra-226 irradiator. Error
bars were calculated to two standard deviations.
Blue Values for Ra-226 and Control
r 2.5
200
f.5
10
r 25
40
75
125
150
200
Blue
Ra-226
100
50-f
or
10
1
100
1000
Dose (Rads) on Color Reference Chart
Figure 5.15 Blue Values for Ra-226 and Calibration Curve. Each blue point
represents the average values of each dose on the color reference charts for all of
the control cards in the evaluation. Each black point represents the average
value for all ten cards at each dose irradiated in the Ra-226 irradiator. Error
bars were calculated to two standard deviations.
5.4 Co-60 EXPOSURES
The Co-60 series did not test for angular dependence so only card one is
displayed.
Only 40 rads and 125 rads were tested with the Gammacell Co-60
irradiation unit. All ten cards in the set were compared to each other as well as the set
control in a bar graph. Error bar values were taken from the Adobe Photoshop 7.0®
histograms. These graphs can be seen in Appendix D. Intensity values for cards one
through ten was averaged for 40 rads and plotted on the calibration curve for
comparison with the 125 rads color reference chart values.
calculated to two standard deviations.
The error bars were
39
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Figure 5.16 Co-60 40 and 125 rads SIRAD badges. SIRAD badge number one
irradiated to 40 rads (left) and 125 rads (right) by the Gammacell 220 Co-60
irradiation unit.
Table 5.4 Averaged Color Readings for Co-60 Irradiated Cards
Averaged Color Readings
for Co-60 Irradiated Cards,
n = 10 per dose
Dose delivered
to cards (rad)
Parameter
Measured
125
Luminosity
Red
Green
Blue
66.72
61 .496
53.461
152.118
Standard Deviations of the
Averaged Color Readings
for Co-60 Irradiated Cards
Parameter
Measured
125
Luminosity
Red
Green
Blue
5.243001685
1.644903239
7.053607115
5.61 9567401
Luminosity Values for Co-60 and Calibration Curve
250
200
10
25
150
40
100
Luminosity
Co-60
75
125
50
20U
0
1
10
100
1000
Dose (Rads) on Color Reference Chart
Figure 5.17 Luminosity Values for Co-60 and Calibration Curve. Each gray
point represents the average values of each dose on the color reference charts for
all of the control cards in the evaluation. Each black point represents the
average value for all ten cards at 40 rads irradiated by the Gammacell Co-60
irradiation unit compared to 125 rad values. Error bars were calculated to two
standard deviations.
Figure 5.18 Red Values for Co-60 and Calibration Curve.
Each red point
represents the average values of each dose on the color reference charts for all of
the control cards in the evaluation. Each black point represents the average
value for all ten cards at 40 rads irradiated by the Gammacell Co-60 irradiation
unit compared to 125 rad values. Error bars were calculated to two standard
deviations.
41
Green Values for C 0-60 and Calibration Curve
250
200
----i
--
150
100
10
1
- --
1000
Dose (Rads) on Color Reference Chart
Figure 5.19 Green Values for Co-60 and Calibration Curve. Each green point
represents the average values of each dose on the color reference charts for all of
the control cards in the evaluation. Each black point represents the average
value for all ten cards at 40 rads irradiated by the Gammacell Co-60 irradiation
unit compared to 125 rad values. Error bars were calculated to two standard
deviations.
Blue Values for Co.60 and Calibration Curve
250
I
200
L
150
1. Blue
100
0-
50
1
10
100
1000
Dose (Rads) on Color Reference Chart
Figure 5.20 Blue Values for Co-60 and Calibration Curve. Each blue point
represents the average values of each dose on the color reference charts for all of
the control cards in the evaluation. Each black point represents the average
value for all ten cards at 40 rads irradiated by the Gammacell Co-60 irradiation
unit compared to 125 rad values. Error bars were calculated to two standard
deviations.
42
6. DISCUSSION
6.1 CONTROL CARDS
According to the histograms created to compare all of the set controls with the
overall control, all of the set controls from each series, Cs-137, Ra-226, and Co-60,
showed slight or no variance among each other. This is due to the luminosity, red,
green, and blue statistics taken from the histograms created by Adobe Photoshop 7.O®
for each color and each card being similar.
The calibration curves created by
averaging all of the control cards together show the red intensity values being the most
consistent and the best indicator. This comparison shows consistency in the make up
and capabilities of the SIRAD cards.
6.2 Cs-137 EXPOSURES
The Cs- 137 exposures showed all of the cards fell within the standard
deviations of the color reference charts calculated by Adobe Photoshop 7.O®. Since
all the cards in the set fell within the control cards standard deviation and closely
resembled each other, it is assumed that there was no appreciable attenuation or
shielding taking place. When compared to the set control, card number ten, which was
raised to a 15 ° angle to test for angular dependence, kept the same pattern as the rest
of the cards in the set. This shows that there was no angular dependence expressed in
this evaluation between
00
and 150.
43
When the intensity values for each dose were averaged and compared to the
calibration curve there was a slight inconsistency with the 40 rad readings for
luminosity, green and blue. Red intensity readings were all within two standard
deviations.
6.3 Ra-226 EXPOSURES
Results from the Ra-226 series were not as clear as those in the Cs-137 and
Co-60 series. According to standard deviation values computed by Adobe Photoshop
7.0®, the 2.5 rad and 7.5 rad card sets were found to be within the error bounds of the
set control. These values were calculated from equations on the set control card graph
(see Appendix C). Based on an assumption of linearity between two points on the
graph, the standard deviations for 2.5 rads and 7.5 rads were calculated by taking the
average of the standard deviations from 0 rads and 5 rads and 5 rads 10 rads,
respectively.
The 5 rads card set did not display statistically similar intensity readings for
red and for cards number one and eight for luminosity. The 10 rads card set showed
inconsistent values on all of the red intensity readings except for cards number six,
seven, and ten. Luminosity readings showed cards number three and five outside of
the set control values. It also showed green intensity readings for card number three
not meeting the set controls values.
44
As a result of card sets 5 rads and 10 rads showing deviations from the set
control, gamma attenuation calculations were done.
Using the mass attenuation
coefficient, --, for Tissue-Equivalent Plastic7, which was used to represent the UV
p
film, attenuation was calculated. A value of .9998 was calculated for the .01 cm film
concluding that there was no attenuation occurring. Attenuation was also calculated
for the total thickness, .11cm, of the card and the UV film combined, and resulted in a
value of .9982. Attenuation for the UV film was calculated using Ra-226 gamma
emitting progeny. Calculations were done for the gamma energies most probable per
decay. Table 6.1 displays the results to these calculations.
Value was taken from the Handbook of Health Physics and Radiological Health, 3 ed, edited by
Bernard Shleien, Lester A. Slaback, Jr. and Brian Kent Birky. Baltimore, Williams & Wilkins, 1998,
5-24
45
Table 6.1 Gamma Ray Attenuation for selected Ra-226 progeny.
The gamma energies which were the most probable per decay were
chosen to check for attenuation of the UV film. The equation used
was: 1/10 = e-it, where 1/10 is the fraction of gamma-ray intensity
transmitted through an absorber of thickness, t, per gamma-ray
intensity at zero absorber thickness. (Cember, pg. 134) The energy
absorption coefficient and density for Tissue Equivalent plastic were
used to represent the black UV ifim. Gamma energies, energy
absorption coefficient, and density were found in Table 8.14, Table
5.1, and Table 5.4, respectfully, in the Handbook of Health Physics
and Radiological Health, 3rd ed.
Gamma Ray Attenuation for the Ra-226 Series
Isotope
Ra-226
Rn-222
Pb-214
Bi-214
Gamma
E(MeV)
0.1862
0.512
0.0108
0.29521
0.35192
0.60931
1.1203
1.7645
(cm /g)
0.014504
0.094924
3.7386
0.118162
0.110862
0.088067
0.065475
0.05262
p
(glcm3)
p(cm1)
1.127
1.127
1.127
1.127
1.127
1.127
1.127
1.127
0.016346
0.106979
4.213402
0.133169
0.124941
0.099252
0.07379
0.059303
Thickness
of film
(cm)
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
1/10
0.999837
0.998931
0.958741
0.998669
0.998751
0.999008
0.999262
0.999407
Since there was no attenuation found, the Ra-226 needle is certified, and all of
the cards were consistent with each other within their sets, the irradiation times were
recalculated and all graphs, numbers, and charts were double checked. There were no
discrepancies found. However, when the intensity values were averaged for each dose
and then compared with the calibration curve, none of the intensity values fell within
two standard deviations of the control values. This indicates the possibility that the
SIRAD cards may be energy dependent.
Card number ten, which was tested for angular dependence at an angle of 450,
showed consistency with the rest of the cards in its respective set. There was no
angular dependence observed on the card between a 00 and 45° angle.
6.4 Co-60 EXPOSURES
The Co-60 irradiator was used for the 40 rad and the 125 rad sets. The timer
on the irradiator only allowed for time in the unit of seconds. To get a dose of 40 rads
and 125 rads, calculations yielded a time of 1.72 seconds and 5.37 seconds,
respectively. Since these numbers were unable to be used, 2 seconds for the 40 rads
set and 6 seconds for the 125 rads set was used. Knowing that higher doses would
come out on the cards, adjustments in the calculations were made to account for the
added time in the irradiator. These adjustments showed the cards were supposed to
receive doses of 46.56 rads and 139.67 rads. However, when the cards went through
the evaluation process and also looking at them visually, it was evident that the new
adjusted doses were incorrect.
Since the irradiation times were so short, it was determined that the cards were
receiving a traveling dose. Victoreen Condenser R-Meters were used to determine this
dose. Out of six trials between two R-Meters, an average traveling dose of 77 rads
was calculated. This number was added onto the adjusted doses. The 40 rads card
had received a dose of 123.56 rads and the 125 rads card received a dose of 216.67
rads. Using the corrected doses the 125 rads card exceeded the cards capability of
47
determining its dose and the 40 rads card set was renamed as the 125 rads set. The
new 125 rads set according to Adobe Photoshop 7.0® standard deviation showed no
variances between the cards and the set control at values for 125 rads. This was also
true when the 125 rads set was compared to the calibration curve.
7. CONCLUSION
The Self-indicating Instant Radiation Alert Dosimeter was found to have no or
slight energy dependence among the isotopes of Cs-137, and Co-60. However, it is
possible that the card does have an energy dependence based on the results from the
Ra-226 series. The evaluation displayed no angular dependence between
00
and 45°.
Based on the findings of this evaluation, it is recommended that JP Labs examine the
cards energy dependence to sources of similar strengths and characteristics of Ra-226.
It is also recommended to test more angles and other isotopes. A human evaluation
for visually reading the dosimeters should be conducted as well.
The dosimeter is an easy, cheap, and beneficial device for first responders to
utilize in their line of work. It will give them an indication of whether or not they
were exposed to any type of radiation which includes the aforementioned isotopes.
However, it may be affected by intense heat such as a fire and false-positive readings
can result if the card is not cared for properly. It will also not be suitable for low dose
monitoring. Therefore, it is strongly recommended to wear another form of dosimetry,
such as a TLD, when using SIRAD. Using this device first responders have the
potential to better monitor themselves and take any appropriate actions to reduce any
further exposure.
BIBLIOGRAPHY
Atomic Energy of Canada Limited Commercial Products. Instruction Manual:
Gammacell 220 Cobalt 60 Irradiation Unit. 6th ed. Ottawa; 1968.
Cember, H. Introduction to Health Physics. 3 ed. New York: McGraw Hill
Companies, Inc.; 1996.
Baum, E.M.; Knox, H.D.; Miller, T.R. Nuclides and Isotopes.
2002.
16th
ed. KAPL, Inc.;
Ebay. Adobe Photoshop 7.0®. Available at:
http ://cgi.ebay.com!ws/eBayISAPI.dll?viewltem&category=8673 2&item7 14455703
1&rd=l. Accessed 21 March 2005.
Epson. Epson Perfection 2480 PHOTO. Available at: http://www.epson.com/cgibinlStore/consumer/consDetail.jsp?BV UseBVCookie=yes&infoType=Specs&oid=4
6048265&category=Products. Accessed 9 March 2005.
Hall, E.J. Radiobiology for the Radiologist.
Williams and Wilkins; 2000.
ed. Philadelphia: Lippincott
JP Labs. What is SIRAD. Available at:
http://www.jplabs.com/html/what_is_sirad.html. Accessed 5 March 2005 (a).
JP Labs. Effect of Ambient Conditions. Available at:
http://www.jplabs.com/html/effectof ambient conditions.html. Accessed 5
March 2005 (b).
JP Labs. Need for SIRAD. Available at:
http://www.jplabs.com/html/need for sirad.html. Accessed 5 March 2005 (c).
JP Labs. Manual. Available at: http ://www. jplabs.com!html/manual .html. Accessed
5 March 2005 (d)
JP Labs. What SIRAD Will Do. Available at:
http://www.jplabs.com/html/what_sirad will do.html. Accessed 5 March 2005
(e).
JP Labs. What SIRAD Will Not Do. Available at:
http://www.jplabs.com/html/whatsirad will_not do.html. Accessed 5 March
2005 (f).
4']
JP Labs. Features. Available at: http://www.jplabs.com!html/features.html.
Accessed 5 March 2005 (g).
Knoll, Glenn F. Radiation Detection and Measurement. 31 ed. New York: John
Wiley & Sons, Inc.; 2000.
Martin, J.E. Physics for Radiation Protection. New York: John Wiley and Sons, Inc.;
2000.
Oregon State University Radiation Center Health Physics Procedure 18, Rev. #8.
Maintenance and Calibration Procedures for Radiation Protection Instrumentation
(Including Operator training Manual and Operating Procedures for the Radiation
Center gamma instrument Calibration Facility. Oct. 2004.
Oregon State University Radiation Center Health Physics Procedure 21, Rev. #5.
Operating Procedures for the gamma Irradiation Facility. Feb. 2000.
Shleien, B., Slaback, Jr, L.A., Birky, B.K. Editors. Handbook of Health Physics and
Radiological Health. 3 ed. Baltimore, MD: Williams & Wilkins; 1998
Union Miniere. Radium Source Certificate No. 33871. 22 March 1974.
US Environmental Protection Agency, (EPA). Cesium. Available at:
www.epa.gov/radiationlradionuclides/cesium.html. Accessed 4 April 2005 (a).
US Environmental Protection Agency, (EPA). Cobalt. Available at:
www.epa.gov/radiationlradionuclides/cobalt.html. Accessed 4 April 2005 (b).
US Environmental Protection Agency, (EPA). Radium. Available at:
www.epa.gov/radiation!radionuclides/radium.html. Accessed 4 April 2005 (c).
Victoreen Instrument Company, The. Instruction Manual Condenser R-Meter. The
Victoreen Instrument Company. Cleveland, Ohio: 1-3.
51
APPENDICES
52
Appendix A
Control Card Picture and Graphs
0
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40
5
75
WaminglO
125
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adiation sensing Sinp from prolonged
eposelo UV#eunilgltt & hlgl tsmpsraass
Figure A-i Blank set control card from the Cs-137 2.5 rads set.
Cs-137 Set Controls Compared with Overall Control at 0 rads
240
220
D Lum
200
I
UG
180
160
140
120
OralI
25
5
75
10
40
125
Control
Card Set
Figure A-2 The Cs-137 set controls (blank cards) compared to the overall control
card at 0 rads, where the intensity for luminosity (grey bars), red, green, and blue
are shown for each set control in the Cs-i37 Series and the overall control card.
53
Ra-226 Set Controls Compared with Overall Control at 40 reds
250
200
100
50
0
Owrall Control
25
5
7.5
10
Card S.t
Figure A-3 The Ra-226 set controls (blank cards) compared to the overall control
card at 40 rads, where the intensity for luminosity (grey bars), red, green, and
blue are shown for each set control in the Ra-226 Series and the overall control
card.
Co-60 Set Control Compared with Overall Control at 200 Rads
160
140
120
Lum
R
G
B
100
80
3
60
40
20
0
Overall Control
125
L- ___
____
Figure A-4 The Co-60 set controls (blank cards) compared to the overall control
card at 200 rads, where the intensity for luminosity (grey bars), red, green, and
blue are shown for each set control in the Co-60 Series and the overall control
card.
54
Appendix B
Cs-137 Pictures and Graphs
All six doses were evaluated in the Cs-137 series. Card number ten was used
to test for angular dependence (AD) at
Card number one and number ten are
150.
displayed to show the similarity in their dose and color.
Cs-137
2.5 Rads Card Set
0
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Rac1.ton
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S.n.
$b1p*01
WuulNØI I t
Ismsm,,s
ProSsd R.dison Ssnsi SPip frON .Id
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I MØ 00npsrtss
Figure B-i Cs-137 2.5 rads SIRAD badges. SIRAD badge number one irradiated
to 2.5 rads by the Cs-137 irradiator (left) and SIRAD badge number 10
irradiated to 2.5 rads by the Cs-137 irradiator (right) are shown side by side to
show the uniformity of the color on the sensing strips. Card number 10 was
placed at a 15 angle to test for angular dependence.
55
Cs-137 2.5 Rads
230
220
210
R
G
B
Lum
200
190
180
170
160
150
1
2
3
4
6
5
7
9
8
lOAD
Set
Control
Card
Figure B-2 Cs-137 2.5 rads card set compared to the set control. Each individual
card is listed 1-lOAD on the x-axis. The tenth card in this set was used to test for
angular dependence, AD. The set control card values are for 2.5 rads. Since
there is not a color chart for 2.5 rads, the values were calculated from equations
taken from figure B-3. The y-axis represents the intensity readings for
luminosity (grey bars), red, green, and blue obtained from the 2.5 rads
histograms created by Adobe Photoshop 7.O®.
Cs-137 2.5 Rads Set Control
230
A
--
180
-
---
y=-5O531Ln(x).27118
=
130
80
30
-20
Intensity
Figure B-3 Cs-137 2.5 rads set control graph. Histogram readings for luminosity
(black diamonds), red (red squares), green (green triangles), and blue (blue
squares) were plotted for each color on the set control card. These readings were
graphed with their corresponding dose.
calculated using the equation of the line.
Intensity values for 2.5 rads were
56
5 Rads Card Set
Cs-137
-
0
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Radiation
Hazard 5
Warning ¶0
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A
0
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Warning 10:
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Pvo*ect "Radiation Senadng SE" tritoi prolonged
exposures to LNisunkl I ti UIIIpISISSS
exposuree to UViunhight & hhs
Figure B-4 Cs-137 5 rads SIRAD badges. SIRAD badge number one irradiated
to 5 rads by the Cs-137 irradiator (left) and SIRAD badge number 10 irradiated
to 5 rads by the Cs-137 irradiator (right) are shown side by side to show the
uniformity of the color on the sensing strips. Card number 10 was placed at a
angle to test for angular dependence.
15°
Cs-I 37 5 Rads
Lum
22j
R
G
B
iølfl!
9
lOAD
Set
Control
Card
Figure B-S Cs-137 5 rads card set compared to the set control. Each individual
card is listed 1-lOAD on the x-axis. The tenth card in this set was used to test for
angular dependence, AD. The set control card values are for 5 rads. The y-axis
represents the intensity readings for luminosity (grey bars), red, green, and blue,
obtained from the 5 rads histograms created by Adobe Photoshop 7.0®.
57
Cs -137
7.5 Rads Card Set
0
EXPIRES ON JUNE 30, 2005
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eposur,s o UVun5ght & h,gh Ienpefatur,,
Figure B-6 Cs-137 7.5 rads SIRAD badges. SWAD badge number one irradiated
to 7.5 rads by the Cs-137 irradiator (left) and SIRAD badge number 10
irradiated to 7.5 rads by the Cs-137 irradiator (right) are shown side by side to
show the uniformity of the color on the sensing strips. Card number 10 was
placed at a 15° angle to test for angular dependence.
Cs-I 37 7.5 Rads
240
220
200
Lum
G
B
180
160
140
120
1
2
3
4
5
6
7
8
9
lOAD
Set
Control
Card
Figure B-7 Cs-137 7.5 rads card set compared to the set control. Each individual
card is listed 1-lOAD on the x-axis. The tenth card in this set was used to test for
angular dependence, AD. The set control card values are for 7.5 rads. Since
there is not a color chart for 7.5 rads, the values were calculated from equations
taken from figure B-8. The y-axis represents the intensity readings for
luminosity (grey bars), red, green, and blue, obtained from the 7.5 rads
histograms created by Adobe Photoshop 7.0®.
Cs-I 37 7.5 Rads S.t Control
250
y =-498.77Ln(x) +2673.6
y =-127.11Ln(x) + 678.54
= 0.9778
200
-'---
y = -115.5Ln(x) + 618.89
--A-----
-
R2
= 0.9681
R2 = 0.9871
150
y-90.4o6Lfl(X)+476.39_
0
-50
Into no Ity
Figure B-8 Cs-137 7.5 rads set control graph. Histogram readings for luminosity
(black diamonds), red (red squares), green (green triangles), and blue (blue
squares) were plotted for each color on the set control card. These readings were
Intensity values for 7.5 rads were
graphed with their corresponding dose.
calculated using the equation of the line.
Cs-137
10 Rads Card Set
0
Li
EXPIRES ON JUNE 30. 2005
0
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expoeures to UV/sunhight & high temperatures
Figure B-9 Cs-137 10 rads SIRAD badges. SIRAD badge number one irradiated
to 10 rads by the Cs-137 irradiator (left) and SIRAD badge number 10 irradiated
to 10 rads by the Cs-137 irradiator (right) are shown side by side to show the
uniformity of the color on the sensing strips. Card number 10 was placed at a 15°
angle to test for angular dependence.
59
Cs-137 10 Rads
220
200
Lum
R
G
180
a
160
140
120
100
1
4
3
2
5
6
7
8
lOAD
9
Set
Control
Card
Figure B-b Cs-137 10 rads card set compared to the set control. Each individual
card is listed 1-lOAD on the x-axis. The tenth card in this set was used to test for
angular dependence, AD. The set control card values are for 10 rads. The y-axis
represents the intensity readings for luminosity (grey bars), red, green, and blue,
obtained from the 10 rads histograms created by Adobe Photoshop 7.0®.
Cs-137
40 Rads Card Set
0
0
Rathahon
-
0
EXPIRES ON JUNE 30, 2001
Warning 10
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Figure B-il Cs-137 40 rads SIRAD badges.
a0atx ,enang Str'p
jrex
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UV.sunhigII &
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temperatuils
SIRAD badge number one
irradiated to 40 rads by the Cs-137 irradiator (left) and SIRAD badge number 10
irradiated to 40 rads by the Cs-137 irradiator (right) are shown side by side to
show the uniformity of the color on the sensing strips. Card number 10 was
placed at a 15 angle to test for angular dependence.
Cs-137 40 Rads
230
210
190
170
o Lum
G
UB
150
I
130
110
90
70
50
2
1
3
4
5
8
8
7
9
lOAD
Set
Control
Card
Figure B-12 Cs-137 40 rads card set compared to the set control. Each individual
card is listed 1-lOAD on the x-axis. The tenth card in this set was used to test for
angular dependence, AD. The set control card values are for 40 rads. The y-axis
represents the intensity readings for luminosity (grey bars), red, green, and blue,
obtained from the 40 rads histograms created by Adobe Photoshop 7.0®.
Cs-137 - 125 Rads Card Set
0
EXPIRES ON JUNE 30, 200
Radiabon
40
Haud 5
i
0
RdIi0iøti Ssnsn Sb
4l
5
L.j
11
itjj
IsQawii;:
Pr
EXPIRES ON JUNE 30.2005
ptoongsd
p
slnI.
'J
Figure B-13 Cs-137 125 rads SIRAD badges.
from
,
SIRAD badge number one
irradiated to 125 rads by the Cs-137 irradiator (left) and SIRAD badge number
10 irradiated to 125 rads by the Cs-137 irradiator (right) are shown side by side
to show the uniformity of the color on the sensing strips. Card number 10 was
placed at a 15° angle to test for angular dependence.
61
Cs-I 37 125 Rads
180
160
140
R
o
58
Lum
120
1
2
3
4
5
6
7
8
9
lOAD
Set
Control
Card
Figure B-14 Cs-137 125 rads card set compared to the set control.
Each
individual card is listed 1-lOAD on the x-axis. The tenth card in this set was used
to test for angular dependence, AD. The set control card values are for 125 rads.
The y-axis represents the intensity readings for luminosity (grey bars), red,
green, and blue, obtained from the 125 rads histograms created by Adobe
Photoshop 7.O®.
62
Appendix C
Ra-226 Pictures and Graphs
The SIRAD cards in the Ra-226 series were subjected to 2.5 rads, 5 rads, 7.5
rads, and 10 rads. Card number ten was used to test for angular dependence (AD) at
45°. Card number one and number ten are displayed to show the similarity in their
dose and color.
Ra-226
2.5 Rads Card Set
0
__
d
Evaajae
CI) Ptsl.d R.&slon Ssnslç S
0
EZNNE$ ON JUNE 31, 2N
I
Evacusle 25
-00
CbU&It.S
from _ k...eJ
-
EXMNES CII JUNE 30. 200
,5
00
I&iicss
PrIS3 R.dEslen S.nsEng S
from poIongsd
Figure C-i Ra-226 2.5 rads SIRAD badges. SIRAD badge number one irradiated
to 2.5 rads by the Ra-226 needle (left) and SIRAD badge number 10 irradiated to
2.5 rads by the Ra-226 needle (right) are shown side by side to show the
uniformity of the color on the sensing strips. Card number 10 was placed at a 45°
angle to test for angular dependence.
63
.PtPlIIIIII WI i'I III ri
u
Ii" liii" liii
I
r'i
in r i
iii i i
i
'
P
liii" Ii"
I
Ii,
Figure C-2 Ra-226 2.5 rads card set compared to the set control. Each individual
card is listed 1-lOAD on the x-axis. The tenth card in this set was used to test for
angular dependence, AD. The set control card values are for 2.5 rads. Since
there is not a color chart for 2.5 rads, the values were calculated from equations
taken from figure C-3. The y-axis represents the intensity readings for
luminosity (grey bars), red, green, and blue, obtained from the 2.5 rads
histograms created by Adobe Photoshop 7.O®.
Ra-226 2.5 Rads Sot Control
235
--
y
185
--
-
y
135
85
35
-
a.
-
- -.--------
-109.87Ln(x) + 586.88
= 0.992
-
-497.6lLn(x) + 2663.2
= 0.9528
y
-.-.-.
______
-121.O8Ln(x) +641.69
= 0.9827
-
___________________
_______
y
-81.085Ln(x) +42494
= 0.9822
-
-15
10
___100
.
.
_idoo
nt.nsity
Figure C-3 Ra-226 2.5 rads set control graph. Histogram readings for luminosity
(black diamonds), red (red squares), green (green triangles), and blue (blue
squares) were plotted for each color on the set control card. These readings were
graphed with their corresponding dose. Intensity values for 2.5 rads were
calculated using the equation of the line.
Ra-226
5 Rads Card Set
0
EXPIRES OH JUNE 30 200'
0
EXPIRES ON JUNE 30, 200
4°
EIt_
PoI. RMI.. S..
kt from pmêorsgsd
sxpoorrb UV1ugN&
Pvo,ti Radaon S.ning Sfrtp. from pooêoriged
*smIrss
.,osurss
hç I.mpsmtes
Figure C-4 Ra-226 5 rads SIRAD badges. SIRAD badge number one irradiated
to 5 rads by the Ra-226 needle (left) and SIRAD badge number 10 irradiated to 5
rads by the Ra-226 needle (right) are shown side by side to show the uniformity
of the color on the sensing strips. Card number 10 was placed at a 45° angle to
test for angular dependence.
Ra.226 5 Rads
D Lum
R
G
Figure C-5 Ra-226 5 rads card set compared to the set control. Each individual
card is listed 1-lOAD on the x-axis. The tenth card in this set was used to test for
angular dependence, AD. The set control card values are for 5 rads. The y-axis
represents the intensity readings for luminosity (grey bars), red, green, and blue,
obtained from the 5 rads histograms created by Adobe Photoshop 7.0®.
65
7.5 Rads Card Set
Ra-226
I
0
Radiason
Hazard
1
vS
0
EXPIRES ON JUNE
EXPIRES ON JUNE 30, 2005
Radiation
40
5
5
E1It$
vvarntng ioi
<I1
warning 10
1
Evacuate 25
Protect Radiation Sesut9 Stnp from prolonged
Protect RaaIdto- Sensing Str
exposures to UV,SU'IIIqnI & r
4
exposiars to LJV/surthght & hiOS temperatores
from protongad
Figure C-6 Ra-226 7.5 rads SIRAD badges. SIRAD badge number one irradiated
to 7.5 rads by the Ra-226 needle (left) and SIRAD badge number 10 irradiated to
7.5 rads by the Ra-226 needle (right) are shown side by side to show the
uniformity of the color on the sensing strips. Card number 10 was placed at a 45°
angle to test for angular dependence.
Ra-226 7.5 Rads
220
200
180
Lum
UR
G
160
B
140
120
100
1
2
3
4
5
6
7
8
9
lOAD
Set
Contrct
Card
Figure C-7 Ra-226 7.5 rads card set compared to the set control. Each individual
card is listed 1-lOAD on the x-axis. The tenth card in this set was used to test for
angular dependence, AD. The set control card values are for 7.5 rads. Since
there is not a color chart for 7.5 rads, the values were calculated from equations
taken from figure C-8. The y-axis represents the intensity readings for
luminosity (grey bars), red, green, and blue, obtained from the 7.5 rads
histograms created by Adobe Photoshop 7.0®.
Ra-226 7.5 Rads Set Control
--------
225
\
175
y
y = -497.66Lfl(x) + 2658.4
-1 12.83Ln(x) + 600.21
R=0.9828
R'=0.9328
---_________
125
.
75
-
Y_
25
-25
-
_10
t1
Intensity
Figure C-8 Ra-226 7.5 rads set control graph. Histogram readings for luminosity
(black diamonds), red (red squares), green (green triangles), and blue (blue
squares) were plotted for each color on the set control card. These readings were
graphed with their corresponding dose. Intensity values for 7.5 rads were
calculated using the equation of the line.
Ra-226
10 Rads Card Set
a-_125
0
EXMNES 01 JUNE 31, 2155
(
40
uoss te
.40
30 2005
l25
Evacuate
Evacua$e
a__
5
EXPIRES
i
+
itep w.e
RsV*L 11 _ =-
____I___I.
I) Poatct
4.
'Rarâi S.c*
Stlp from pu4ong.d
exposum. te riugtt & ia.gt tee*ir.s
-
Figure C-9 Ra-226 10 rads SIRAD badges. SIRAD badge number one irradiated
to 10 rads by the Ra-226 needle (left) and SIRAD badge number 10 irradiated to
10 rads by the Ra-226 needle (right) are shown side by side to show the
uniformity of the color on the sensing strips. Card number 10 was placed at a 45°
angle to test for angular dependence.
67
Ra-226 10 rad.
220
200
180
R
G
B
o Lum
1160
140
120
100
1
2
3
4
5
6
7
8
9
lOAD
Sot
Control
Card
Figure C-1O Ra-226 10 rads card set compared to the set control.
Each
individual card is listed 1-lOAD on the x-axis. The tenth card in this set was used
to test for angular dependence, AD. The set control card values are for 5 rads.
The y-axis represents the intensity readings for luminosity (grey bars), red,
green, and blue, obtained from the 10 rads histograms created by Adobe
Photoshop 7.O®.
Appendix D
Ra-226 Pictures and Graphs
The Co-60 series did not test for angular dependence so only card one is
displayed.
Only 40 rads and 125 rads were tested with the Gammacell Co-60
irradiation unit.
Co-60
40 Rads Card Set
0
Redtation
Hazard 5
EXPIRES ON JUNE 30. 2005
40
75
Evac:ate2jJJ
Proteot Rd,atior, S.o,,ng Str.p troat proIorja1
.pooras to UV/urtIght S h,gh
Figure D-1 Co-60 40 rads SIRAD badge. SIRAD badge number one irradiated to
40 rads by the Gammacell 220 Co-60 irradiation unit.
Co-60 40 Rads
250
200
R
G
D Lum
150
- 100
-
B
-
-
50
0
1
3
2
4
5
6
7
9
8
Card
L______
10
Set
Control
Figure D-2 Co-60 40 rads card set compared to the set control. Each individual
card is listed 1-10 on the x-axis. The set control card values are for 40 rads. The
y-axis represents the intensity readings for luminosity (grey bars), red, green, and
blue, obtained from the 40 rads histograms created by Adobe Photoshop 7.0®.
Co-60
125 Rads Card Set (Initial)
0
cxs 0 ju.
3S. ass
WsminglO
125
EvscuMs
3
P.d R.d
exposuros
,o0
+
S.
Sp from o
UVIiunliht & hIgh mpsma.s
Figure D-3 Co-60 125 rads SIRAD badge, I.
SIRAD badge number one
irradiated to 125 rads by the Gammacell 220 Co-60 irradiation unit.
70
IuI'
:Firiririririri
iI II riI; iI
I
,ki
!
u 'i
L; I
Ii
I
I
Figure D-4 Co-60 125 rads card set compared to the set control, I.
Each
individual card is listed 1-10 on the x-axis. The set control card values are for
125 rads. The y-axis represents the intensity readings for luminosity (grey bars),
red, green, and blue, obtained from the 125 rads histograms created by Adobe
Photoshop 7.0®.
Co-80 126 Rads
180
160
140
120
R
G
Lum
80
60
40
20
0
2
3
4
5
6
7
8
9
10
Set
Control
200
Card
Figure D-5 Co-60 125 rads card set compared to the set control for 125 rads and
200 rads. Each individual card is listed 1-10 on the x-axis. The set control card
values are for 125 rads. The set control values for 200 rads are also listed for
comparison. The y-axis represents the intensity readings for luminosity (grey
bars), red, green, and blue, obtained from the 125 rads histograms created by
Adobe Photoshop 7.0®.
71
Co-60
125 Rads Card Set (Formerly the 40 Rads Card Set)
0
Z
E)CPIRES ON JUNE 30. 2005
JH.z.td5.
40
WWI
o
o
Protect Ra<j,ation Sensmg Stnp from protonged
exposures to UV/suntight & high temperatures
Figure D-6 Co-60 125 rads SIRAD badge, II. SIRAD badge number one
irradiated to 125 rads by the Gammacell 220 Co-60 irradiation unit. The dose
subjected to this card was formally thought to be 40 rads. It was renamed 125
rads.
Co-60 125 Rads
180
160
140
R
G
B
lo Lum
120
100
80
60
40
20
0
1
2
3
4
5
6
7
8
9
10
Set
Control
L_____________________ --
Card
-
Figure D-7 Co-60 125 rads card set compared to the set control, II.
Each
individual card is listed 1-10 on the x-axis. The values for each card are the same
as those for the 40 rads card set and are compared to the 125 rads values for the
set control card. The y-axis represents the intensity readings for luminosity (grey
bars), red, green, and blue, obtained from the 40 rads histograms created by
Adobe Photoshop 7.0®.