Elayna Mellas
Radiation Safety Officer
Environmental Health & Safety Manager
Clarkson University
Downtown Snell 155
Tel: 315-268-6640 emellas@clarkson.edu
This training course has been partially adapted from slides provided by Steve Backurz, Radiation
Safety Officer of The University of New Hampshire

Nuclear Physics
Subject
Biological Effects
Radiation Exposure and Dose
Uses of Radioactive Material
Radiation Hazards
Radiation Detection
Lab Procedures at Clarkson
Slides
3-30
31-43
44-60
61-66
67-80
81-87
88-115

• Radiation and radioactive materials are valuable tools used in research at Clarkson
• Radio-labeling of biological materials
• Sealed sources in chemistry/engineering
• X-ray diffraction analysis of samples for chemistry and engineering research
• Radioactive materials and X-ray machines are very safe if used properly and simple precautions are followed

 Nucleus
 Contains protons and neutrons




Small Size
Relatively large mass
Extremely large density
Large amount of stored energy
 Orbiting Electrons


Large size
Low density



Orbit nucleus near speed of light
Small amount of energy relative to nucleus
Responsible for chemical bonds

"X" = Element Symbol
"Z" = # Protons
Each element has a unique "Z”
"N” = # Neutrons
Atomic Mass # = "A"
"A" = Z + N = # Protons + # Neutrons
Isotope: same Z, different N, thus different A
A
Z
X

15 Protons
17 Neutrons
A = 32
Z = 15
32
P
15

 Definition: A collection of unstable atoms that undergo spontaneous transformation that result in new
 elements.
An atom with an unstable nucleus will “decay” until it becomes a stable atom, emitting radiation as it decays
 Sometimes a substance undergoes several
 radioactive decays before it reaches a stable state
The “amount” of radioactivity (called activity) is given by the number of nuclear decays that occur per unit time (decays per minute).

 A unit of activity defined by the number of radioactive decays from a gram of radium
 1Curie (Ci) = 2.22 E12 disintegrations/minute (dpm)
 Sub-multiples of the Curie:
 millicurie 1 mCi = 2.22 E9 dpm
 microcurie 1 uCi = 2.22 E6 dpm

 nanocurie 1 nCi = 2,220 dpm
 picocurie 1 pCi = 2.2 dpm
Typical activities at Clarkson are in the

Ci to mCi range

 Disintegrations per minute (dpm)
 Disintegrations per second (dps)
 The SI unit for activity is the becquerel (Bq)
 1 Bq = 1 disintegration/second
 1 Curie (Ci) = 3.7 E10 Bq or 37 GBq
 1 millicurie = 37 MBq
 1 microcurie = 37 kBq

 Any atom or molecule with an imbalance in electrical charge is called an ion
 In an electrically neutral atom or molecule, the number of electrons equals the number of protons
 Ions are very chemically unstable, and will seek electrical neutrality by reacting with other atoms or molecules

 Definition: Energy in the form of particles or waves
 Types of Radiation
 Ionizing: removes electrons from atoms
 Particulate (alphas and betas)
 Waves (gamma and X-rays)
 Non-ionizing (electromagnetic): can't remove electrons from atoms
 infrared, visible, microwaves, radar, radio waves, lasers

10
8
10
6
Radiation Wavelength in Angstrom Units
10
4
10
2
1 10
-2
10
-4
10
-6
Radio
10
-10
10
-8
Infrared l i b i
V s e
Ultra-Violet
Light
10
-6
10
-4
X-Rays Cosmic Rays
Gamma Rays
10
-2
1 10
Photon Energy in Million Electron Volts (MeV)
10

 Alpha particles
 High mass (4 amu) = 2 protons + 2 neutrons
 High charge (+2)
 High linear energy transfer (cause great biological damage)
 Travel a few centimeters in air
 Stopped by a sheet of paper or protective layer of skin
 Not an external hazard
 Concern would be for ingestion or inhalation

 Low mass (0.0005 amu)
 Low charge - can be positively or negatively charged (+/- 1)
 Travel 10 - 20 feet in air
 Stopped by a book
 Shield betas with low density materials such as lucite or plexiglass
 Shielding high energy betas like P-32 with lead can generate more radiation than it shields due to Bremsstrahlung X-rays

 Wave type of radiation - non-particulate
 Photons that originate from the nucleus of unstable atoms
 No mass and no charge
 Travel many feet in air
 Lead or steel used as shielding

Beta Minus Decay:
0
1 n
Beta Plus Decay:
Alpha Decay:
1
1 p
Z
A
X
0

-
1
+ p
1
0

+ +
0
1 n
A-4
Y +
Z-2
4
2


Beta Minus Decay:
(neutron-excess nuclides)
32
P
15
Beta Plus Decay:
(neutron-deficient nuclides)
22
Na
11
Alpha Decay:
(Heavy nuclides above atomic number 82)
210
84
Po
0
 -
32
+
16
S
0

+
+
22
Ne
10
206
82
Pb +
2
4 

 A decay scheme is a graphical representation of radioactive decay
 Depicts the parent/daughter relationship
 Branching fractions and energy levels are shown
137
55
Cs
6.5%
1.176 MeV
 -
93.5% 0.514 MeV

-
137m
56
Ba
0.662 MeV

137
Ba
56

 Half life: The time required to reduce the amount of a
 particular type of radioactive material by one-half
Example: 120 Ci of P-32 (t
1/2
= 14 days)
Decay Law:
A
(t)
= A
(0)
* e
 t
A
(o)
= Initial Activity
A
(t)
= Activity after time "t" t = Decay time
λ = constant = 0.693 / t
1/2 t
1/2
= half-life
140
120
100
80
60
40
20
0
0 14 28 42 56 70 84 98
Time (days)

 Wave type of radiation - non-particulate
 Photons originating from the electron cloud
 Same properties as gamma rays relative to mass, charge, distance traveled, and shielding
 Characteristic X-rays are generated when electrons fall from higher to lower energy electron shells
 Discrete energy depending on the shell energy level of the atom
 Bremsstrahlung X-rays are created when electrons or beta particles slow down in the vicinity of a nucleus
 Produced in a broad spectrum of energies
 Reason you shield betas with low density material

Energy is lost by the incoming charged particle through a radiative mechanism
Beta Particle
-
+
+
Nucleus
Bremsstrahlung
Photon

High Voltage
Power Supply
Current
Anode
Target
Tungsten Filament
Cathode
Glass Envelope
Tube Housing

 kVp - how penetrating the X-rays are
 Mammography - 20 - 30 kVp
 Dental - 70 - 90 kVp
 Chest - 110 - 120 kVp
 mA - how much radiation is produced
 Time - how long the machine is on
 Combination of the above determines exposure

Alpha
Beta Plus
Beta Minus
Gamma
X-Rays
Neutron
Mass
(amu)
4.0000
0.0005
0.0005
0.0000
0.0000
1.0000
Charge Travel Distance in Air
+2
+1
-1
0
0
0 few centimeters few meters few meters many meters many meters many meters

 Radiation: Energy in the form of particles and waves
 Radioactive Material: Material that is unstable and emits radiation
 Contamination: Radioactive material where it is not wanted
 Campfire example: burning logs (radioactive material), heat (radiation), burning embers that escape the controlled area (contamination)

 Radiation deposits small amounts of energy, or "heat" in matter
 alters atoms
 changes molecules
 damage cells & DNA
 similar effects may occur from chemicals
 Much of the resulting damage is from the production of ion pairs

The process by which a neutral atom acquires a positive or negative charge
Alpha Particle
+
+
electron is stripped from atom
The neutral atom gains a + charge
= an ion
-
-
-

Ionization by a Beta particle:
ejected electron
Beta Particle
-
-
-
Colliding
Coulombic Fields
The neutral absorber atom acquires a positive charge -

 Gamma interactions differ from charged particle Interactions
 Interactions called "cataclysmic" - infrequent but when they occur lot of energy transferred
 Three possibilities:
 May pass through - no interaction
 May interact, lose energy & change direction (Compton effect)
 May transfer all its energy & disappear
(photoelectric effect)

An incident photon interacts with an orbital electron to produce a recoil electron and a scattered photon of energy less than the incident photon
Before interaction
-
After interaction
-
Scattered Photon
-
-
Incoming photon
Collides with electron
-
-
Electron is ejected from atom

 Large Doses Received in a Short Time
Period
 Accidents
 Nuclear War
 Cancer Therapy
 Short Term Effects (Acute Radiation
Syndrome 150 to 350 rad Whole Body)
Anorexia
Fatigue
Epilation
Nausea Erythema
Vomiting Hemorrhage
Diarrhea Mortality

Absorbed
Dose (Rads)
10,000
1,200
600
450
100
50
25
5
Effect
Death in a few hours
Death within days
Death within weeks
LD 50/30
Probable Recovery
No observable effect
Blood changes definite
1st Blood change obs

 Doses Received over Long Periods


Background Radiation Exposure
Occupational Radiation Exposure
 50 rem acute vs 50 rem chronic



 acute: no time for cell repair chronic: time for cell repair
 Average US will receive 20 - 30 rem lifetime
 Long Term Effects
 Increased Risk of Cancer
0.07% per rem lifetime exposure
Normal Risk: 30% (cancer incidence)

•
•
•
•
Ionization within body tissues: similar to water
Ionization causes many derivatives to be formed:
 Peroxides
 Free Radicals
 Oxides
These compounds are unstable and are damaging to the chemical balance of the cell. Various effects on cell enzymes and and structures occur.
Radiation is not the only insult responsible
 Pollutants
 Vitamin imbalance (poor diet)
 Sickness and Disease

 Cells often recover from damage
 Repeated Insults may cause damage to be permanent
 Cell Death
 Cell Dysfunction - tumors, cancer, cataracts, blood disorders
 Mitosis (Cell Division) Delayed or Stopped
 Chromosomal breaks
 Organ Dysfunction at High Acute Doses

 Wide variation in the radiosensitivity of various species
 Plants/microrganisms vs. mammals
 Wide variation among cell types
 Cells which divide are more sensitive
 Non-differentiated cells are more sensitive
 Highly differentiated cells (like nerve cells) are less sensitive

 The fetus consists of rapidly dividing cells
 Dividing cells are more sensitive to radiation effects than nondividing cells
 Effects of low level radiation are difficult to measure
 A lower dose limit is used for the fetus

 It is possible to damage the hereditary material in a cell nucleus by external influences like Ionizing radiation, chemicals, etc.
 Effects that occur as a result of exposure to a hazard while in-utero are called teratogenic effects
 Teratogenic effects are thought to be more severe during weeks 8-17 of pregnancy - the period of formation of the body’s organs
 A higher incidence of mental retardation was found among children irradiated in-utero during the bombings of Hiroshima and Nagasaki

Statistically, a radiation exposure of 1 rem poses much lower risks for a woman than smoking tobacco or drinking alcohol during pregnancy
General
< 1 pack/day
> 1 pack/day
2 drinks/day
2-4 drinks/day
> 4 drinks/day
Smoking
Babies weigh 5-9 oz. Less than average
Infant Death
Infant Death
Alcohol
Babies weigh 2-6 oz. Less than average
Fetal alcohol syndrome
Fetal alcohol syndrome
1 in 5
1 in 3
1 in 10
1 in 3
1 in 3 to 1 in 2
1 rem
1 rem
Radiation
Childhood leukemia deaths before 12 years
Other childhood cancer deaths
1 in 3333
1 in 3571

Acute effects
Effects occur after a threshold
Chronic effects?
Effects occur at any level = stochastic
Dose Dose
The stochastic model is more conservative, and is used to establish dose limits for occupational exposure

 Most important factor in determining when effects will occur
 Recovery is less likely with higher dose rates than lower dose rates for an equivalent amount of dose = more permanent damage
 More recovery occurs between intermittent exposures = less permanent damage

 The larger the portion - the more damage (if all other factors are the same)
 Blood forming organs are more sensitive
 A whole body dose causes more damage than a localized dose (such as in medical therapy).
 Dose limits take this into consideration

 Your exposure to radiation can never be zero because background radiation is always present
 Natural Sources - Radon
 Cosmic
 Terrestrial
 Technologically Enhanced Sources (Man-Made)
 Healing Arts: Diagnostic X-rays, Radiopharmaceuticals
 Nuclear Weapons Tests fallout
 Industrial Activities
 Research
 Consumer Products
 Miscellaneous: Air Travel, Transportation of Radioactive
Material

Total exposure Man-made sources
Medical X-Rays
11 Radon 55.0%
Other 1%
Internal 11%
Man-Made 18%
Cosmic 8% Terrestrial 6%
Nuclear
Medicine 4%
Consumer
Products 3%
Total US average dose equivalent = 360 mrem/year

 2 x 10 particles (mostly protons) per second are
 Energy greater than one BILLION ELECTRON
VOLTS
 Interact with atoms in the atmosphere and produce secondary particles

 muons, electrons, photons, and neutrons responsible for cosmic dose

 Major sources
 Potassium - a few grams per 100 grams of ground material
 Thorium and Uranium - a few grams per
1,000,000 grams of ground material
 Dose due mainly to photons originating near the surface of the ground

 Naturally occurring radioactive gas
 Second leading cause of lung cancer
 Estimated 14,000 deaths per year
 Easy to test for
 short and long term tests available
 EPA guideline is 4 pCi/L
 Fixable
 Radon in water from drilled wells can also be an entry method

 A measure of the ionization produced by
X or Gamma Radiation in air
 Unit of exposure is the Roentgen
Q (charge)
X =
M (mass of air)

 Absorbed Dose (or Radiation Dose) is equivalent to the energy absorbed from any type of radiation per unit mass of the absorber
 Unit of Absorbed Dose is the rad
 1 rad = 100 ergs/g = 0.01 joules/Kg
 In SI notation, 1 gray = 100 rads

 One unit of dose equivalent is that amount of any type of radiation which, when absorbed in a biological system, results in the same biological effect as one unit of low LET radiation
 The product of the absorbed dose, D, and the Quality Factor, Q
H = D Q

 Human dose measured in rem or millirem
 1000 mrem = 1 rem
 1 rem poses equal risk for any ionizing radiation
 internal or external
 alpha, beta, gamma, x-ray, or neutron
 In SI units 1 sievert (Sv) = 100 rem
 External radiation exposure measured by dosimetry
 Internal radiation exposure measured using bioassay sample analysis

X and Gamma Rays
Electrons and Muons
Neutrons < 10 kev
>10kev to 100 Kev
> 100 kev to 2 Mev
>2 Mev
Protons > 30 Mev
Alpha Particles
Quality Factor
10
20
10
10
20
1
1
5

 2 Standard reference points
 Shallow Dose: Live skin tissue at an average depth of .007 cm.
 Deep Dose: Internal organs close to the body surface, 1 cm.
 Shallow Dose Equivalent, SDE
 Alpha radiation not a hazard
 consider beta and gamma radiation.
 Deep Dose Equivalent, DDE
 Alpha and Beta radiation not a hazard.
 For gamma, SDE = DDE (typically)

 All radiation types present a hazard
 2 Dose quantities:
 Committed Dose Equivalent, CDE
(specific to a particular organ)
 Committed Effective Dose Equivalent,
CEDE (sum of all organs x weighting factor for importance or each specific organ)

 Used to combine internal and external doses
 Puts all dose on the same risk base comparison, whether from external or internal sources.
 TEDE = CEDE + DDE
 All units are in rems or Sieverts (Sv)
 All regulatory dose limits are based on controlling the TEDE

• Radiation Protection Program Required
• Occupational Limits
 5 rem per year TEDE
 50 rem per year CDE (any single organ)
 15 rem per year lens of the eye
 50 rem per year skin dose
• Members of Public
 100 mrem per year
 No more than 2 mrem in any one hour in unrestricted areas from external sources
• Declared Pregnant Females (Occupational)
 500 mrem/term (evenly distributed)

 Voluntarily informs her employer in writing of pregnancy
 Estimated date of conception
 Dose limit is 10% of occupational limit
(500 mrem)
 Avoid substantial variation in dose
 Form for declaring pregnancy is on web site

 Anticipated Exposures: Less than the minimum detectable dose for film badges (10 mrem/month) - essentially zero
 Average annual background exposure for U.S. population = 360 mrem/year
 State and Federal Exposure Limits =
5000 mrem/year

 Building materials
 Tobacco (Po-210)
 Smoke detectors (Am-241)
 Welding rods (Th-222)
 Television (low levels of X-rays)
 watches & other luminescent products
(tritium or radium)
 Gas lantern mantles
 Fiesta ware (Ur-235)
 Jewelry

Alpha particles from americium-241 (red lines) ionize the air molecules (pink and blue spheres). The ions carry a small current between two electrodes. Smoke particles (brown spheres) attach to ions reducing current and initiate alarm.

 Radioactive Materials (both open and sealed sources such as S-35, P-32, C-14, H-
3, Xe-133, Ra-226, Am-241)
 Gas Chromatographs (sealed sources)
 Liquid Scintillation Counters (sealed sources for internal standards)
 X-ray Diffraction equipment
 Electron microscopes

 Diagnostic
 X-rays
 Nuclear Medicine (Tc-99m, Tl-201, I-123)
 Positron Emission Tomography (PET)
 Therapeutic
 X-rays (Linear Accelerators)
 Radioisotopes
 Brachytherapy (Cs-137, Ir-192, Ra-226)
 Teletherapy (Co-60)
 Radiopharmaceuticals (I-131, Sr-89, Sm-153)

Use of high activity sealed sources to examine structural components such as beams or pipes

 Time: minimize the time that you are in contact with radioactive material to reduce exposure
 Distance: keep your distance. If you double the distance the exposure rate drops by factor of 4
 Shielding:
 Lead, water, or concrete for gamma & X-ray
 Thick plastic (lucite) for betas
 Protective clothing: protects against contamination only - keeps radioactive material off skin and clothes

 Radiation levels decrease as the inverse square of the distance (i.e. move back by a factor of two, radiation levels drop to one fourth)
 Applies to point sources (distance greater than 5 times the maximum source dimension)
I
1
R
1
2
=
I
2
R
2
2 where I = Intensity (exposure rate) at position 1 and 2 and
R = distance from source for position 1 and 2
Source
R
1
R
2
I
1
(mrem/hr)
Position 1
I
2 (mrem/hr)
Position 2

 Gamma Ray Constant to determine exposure rate


(mSv/hr)/MBq at 1 meter
 Hint: multiply (mSv/hr)/MBq by 3.7 to get (mrem/hr)/uCi
 Exposure Rate Calculation, X (mrem/hr) at one meter:
X =

Where, A = Activity (

Ci)
 =
Gamma Ray Constant(mSv/hr)/Mbq
3.7 is the conversion factor

• 5 Curie Cs-137 Source
• Calculate Exposure Rate at 1 meter

= 1.032 E-4 mSv/hr/MBq @ 1 meter
X = 1.032 E-4 * 3.7 * 5 Ci * 1000 mCi/Ci * 1000 uCi/mCi
X = 1909 mrem/hour
X = 1.91 rem/hour

 Effectiveness increases with thickness, d (cm)
 Variation with material, (1/cm)
 attenuation coefficients µ
 High Z material more effective
Water - Iron - Lead good - better - best

 Low energy betas (H-3, C-14, S-35) need no shielding for typical quantities at Clarkson
 Higher energy beta emitters (P-32) should be shielded
 Beta shielding must be low Z material (Lucite,
Plexiglas, etc.)
 High Z materials, like lead, can actually generate radiation in the form of Bremsstrahlung X-rays
 Bremsstrahlung from 1 Ci of P-32 solution in glass bottle is ~1 mR/hr at 1 meter

 Units of Measure
 activity/area (dpm/100 square cm)
 Fixed vs Removable
 Internal Hazards and Entry Routes
 Ingestion
 Inhalation - Re-suspension
 Skin absorption
 Wound Entry

 Can be a very effective means of preventing skin, eyes, & clothing from becoming contaminated
 Gloves (may want double layer)
 Lab Coat
 Eyewear to prevent splashes and provide shielding for high energy beta emitters
 Closed toe footwear
 It is much easier to remove contaminated clothing than to decontaminate your skin!


Watch out where you put your “hot” hands during an experiment
 Monitor yourself and your work area frequently for radioactivity (gloves, hands, feet, etc.)
 Use most sensitive scale on meter (X0.1 or X1)
 Have meter out and handy
 Make sure to wash your hands frequently and after finishing an experiment

Don’t bring radioactive material to lunch or to your home!
 Monitor your work area before and after an experiment


Don’t bring hands or objects near your mouth during an experiment
 Eating, drinking, smoking, applying cosmetics are strictly prohibited in radioisotope use areas
 Never mouth pipette
 Never store personal food items in refrigerators or freezers used for radioactive material or other hazardous material storage

 Make sure you have proper ventilation for your experiments
 When using volatile materials such as
Iodine-125 and some Sulfur-35 compounds, be sure to use a fume hood that has been inspected and certified for proper airflow

 DAC: Derived Air Concentration, an airborne concentration of of radioactive material which if inhaled for 2000 hrs per year will result in 5 rem
CEDE or 50 rem CDE.
 Units are uCi/cc
 Each DAC-hour gives 2.5 mrem of dose.
 ALI: Annual Limit on Intake, A quantity of radioactive material, which if inhaled or ingested, would result in the applicable annual dose limit.
 1 ALI = 5 rem (CEDE) or 50 rem (CDE)
 ALI and DAC Values listed for each nuclide in NHRCR
(He-P 4090)

 TEDE: Total Effective Dose Equivalent
TEDE = DDE + CEDE
Total Dose = External Dose + Internal Dose
 1 rem internal (CEDE) same as 1 rem external (DDE)
 Internal dose is protracted over several years but calculated over 50 years and assigned in the year of intake

 Gas Filled Detectors
 Geiger Mueller (GM)
 Gas Flow Proportional
Counters
• Solid State Detectors
 Germanium Lithium
High Purity
 Silicone Lithium
 Ionization  Silicone Diode
 Cadmium Telluride
 Scintillation Detectors
 Sodium Iodide (NaI)
 Zinc Sulfide (ZnS)
 Anthracene
 Plastic Scintillators

 Ionization detectors
 High Cost
 Survey meters
 Reference class calibration chambers
 Proportional counters
 High cost
 Gross laboratory measurements
 Contamination monitors
 Geiger Mueller (GM) detectors
 Low cost
 Survey meters
 Contamination monitors

 One of the Oldest Detection Methods, Still
Widely Used Today
 Transducer Converts Radiation Energy to
Visible Light
 Visible Light Signals Amplified With
Photomultiplier Tube
 Output PM Tube Signal Processed
 High Efficiency For Photon Detection
Compared To Gas-Filled Detectors

 Laboratory
 Liquid Scintillation Counters
 gross counting
 spectroscopy
 Quenching
 Field
 Low Level Radiation Survey Instruments
 Thyroid monitoring for Iodine uptakes

 Check Physical Condition
 Cables, Connections, Damage
 Check for Current Calibration (License
Requirement)
 Battery Check
 Zero Check
 Response check prior to use
 Select Proper Scale
 Response Time (Fast or Slow?)
 Audio (On or Off)

 A radiation detector will not detect every disintegration from a source (i.e., they are not 100% efficient)
 Counts per minute (cpm) is the number of disintegrations that a detector “sees”
 The efficiency of a detector is determined by the following:
Efficiency = net cpm / dpm
= gross cpm – background cpm / dpm

• U. S. Nuclear Regulatory Commission
 Regulates the nuclear industry pursuant to the

Atomic Energy Act
Regulatory guides published to describe methods for complying with regulations
• Agreement States
 Some states have entered into an agreement with the NRC to regulate by-product material
(and small quantities of source and special
 nuclear material)
Currently, 30 states are agreement states including New York

 Activities are licensed by the State of New York
 Radiation Safety Committee has responsibility to review, approve, and oversee activities
 Radiation Safety Officer (RSO) runs program
 Clarkson is required to:
 Train individuals that use sources of radiation
 Train non-radiation workers that work in the vicinity of radiation sources
 Monitor and control radiation exposures
 Maintain signs, labels, postings
 Manage and properly dispose of radioactive waste

• Only RSO is authorized to order radioactive material
• Use the Radionuclide Purchase Request Form
• Complete form and fax to RSO at 268-7118
• Be sure to state any special ordering instructions
(preferred delivery date, fresh batch, etc.)
• Packages are received by RSO, checked for contamination, logged in, and delivered to the lab on the same day as receipt

 Tritium (Hydrogen-3)
 12.3 year half life
 Very low energy beta (0.0186 MeV max)
 No shielding needed
 Surveys by wipe method counted on LSC
 Carbon-14
 5730 year half life
 Low energy beta (0.156 MeV max)
 Shielding not needed
 Spot checks with GM are possible but contamination surveys using wipes are necessary

 Phosporous-32
 14.3 day half life
 High energy beta (1.710 MeV max)
 Shield with low Z material such as plastics
 Do not use lead shielding
 Wear safety glasses to shield eyes
 Ring badges are required for handling millicurie
 quantities
GM survey meter required
 Avoid handling containers for extended periods

 Sulfur-35



87.4 day half life
Low energy beta (0.167 MeV max)
Same general precautions as for C-14
 Should be handled in a fume hood
 Nickel-63


100.1 year half life
Low energy beta (0.066 MeV max)


Gas chromatographs with electron capture detector cells
No shielding needed

 Posting
 New York Notice to

Employees form
Caution Radioactive
Materials or X-Rays
• Labels
 All containers (unless exempt) must be


 labeled
With “Caution – Radioactive Material”
Should include radionuclide, quantity, date, initials, radiation levels, etc.

 Right to report any radiation protection problem to state without repercussions
 Responsibility to comply with the Radiation
Protection Program and the RSO's instructions pertaining to radiation protection
 Right to request inspection
 in writing
 grounds for notice
 signed
 Responsibility to cooperate with NY State inspectors during inspections and RSO during internal lab audits

 Required by License and NY Regulations
 Security and Control of Radioactive Material
Unrestricted area
Controlled area
Unrestricted area Unrestricted area
Restricted area

 Licensed RAM must be secured against unauthorized removal at all times
 Must maintain constant surveillance for any radioactive material outside a restricted area
 Lock labs containing radioactive material if last one out even if it’s “just for a minute”

Challenge all unknown individuals with “May
I help you?”
 OK to ask for ID
 Report to supervisor if suspicious

 The goal of radiation protection is to keep radiation doses As Low As Reasonably
Achievable
 Clarkson is committed to keeping radiation exposures to all personnel ALARA
 What is reasonable?
 Includes: -State and cost of technology
-Cost vs. benefit
-Societal & socioeconomic considerations

•
•
•
•
•
Source sign out/in logs
Physical inventories
Leak Tests
Alpha sources every 3 months
Others every 6 months
Lost, stolen, or damaged sources must be reported to RSO
May require notification of the State

• Clarkson Radiation Protection Program specifies
 Monitor all work areas at least once a week
 Instrument surveys and/or wipe surveys should be done after each experiment or more often if needed
 Isotope storage area must be surveyed at least once per month if no work is in progress
 Must keep records of all required surveys for inspection by RSO and state inspectors
• Survey equipment calibration intervals (12 months)

• Randomly survey selected areas outside of normal radioisotope use areas at least once a month to ensure there is no spread of contamination
• Using a form with map of your lab on it is strongly recommended to make documenting surveys easier
• Check wherever human hands and feet can go.
• A good rule of thumb for determining if contamination is present is to look for 2X background
• Common contamination sites include soap/towel dispensers, phones, chairs, desk tops, drawer and door handles, refrigerator handles, pens and log books, and the survey meter itself

• Direct monitoring with a Gieger Mueller detector can be performed when using P-32 and other high energy beta or gamma emitters
• Wipe surveys for removable contamination must be used for low energy beta emitters (H-3, C-14,
S-35)
• Wipes are counted in a liquid scintillation counter
• Direct monitoring for low energy gamma emitters should be done with a low energy gamma scintillation probe (NaI crystal)

• Wear gloves
• Although a moistened swab or filter paper is more efficient, a dry filter or soft absorbent paper be used
• Use uniform moderate pressure and wipe an area of at least
100 cm 2 (about 4” X 4” or standard “S” swipe)
• Keep each wipe separate to avoid cross contamination
• Keep a record of the area wiped so that you know where the contamination is located if the wipe comes up “hot”
• Place the wipe into a liquid scintillation vial, add cocktail, and count according to manufacturer’s procedure or your lab specific procedure
• Results should be in dpm/100 cm 2

• Contamination surveys must be documented
• Record the following
 Date performed


Areas surveyed (map is best)
Results in dpm/100 cm 2 or mR/hour as



 applicable
Initials or name of surveyor
Instrument used and date of calibration
Action taken if contamination is found
Be sure to document all post-spill clean up surveys very well!

• Only for isotopes with half-lives less than 100 d
• Keep all isotopes separate
• Must keep an inventory with amount of activity
• Remove or obliterate all radioactive labels prior to disposal
• Store in labeled receptacle with clear plastic liner
• Hold for 10 half-lives
• Survey with appropriate detector and confirm indistinguishable from background
• Dispose of without regard to radioactivity

• Use “environmentally friendly” cocktail (water soluble)
• If tolulene/xylene based media must be used, keep separate
• Must keep an inventory with amount of activity
• Keep LSC separate from other liquid wastes
• Store vials in flats, and check with RSO regarding method of disposal
• Do not mix these with cocktails containing other radioactive materials

• Readily soluble or readily dispersable biological materials in water may go down the drain if
• No other hazard is present
• The concentration does not exceed the allowable monthly average concentration
• The total amount of radioactivity does not exceed
50

Ci/day
• The sink has been approved by the RSO and is appropriately designated and labeled
• Must keep an inventory with amount of activity

• When cleaning up a spill, place absorbent material around the edges of the spill and clean from the outside edges toward the center to avoid spreading
• Place materials used to clean the spill into appropriate radioactive waste containers
• Notify others in the lab of the spill to prevent inadvertent spread of contamination
• After clean-up, monitor all work areas using survey meter or wipe surveys, as applicable
• Survey your hands, feet, clothing and all other materials that may have come in contact with the spilled material

• A minor spill is one that involves small quantities, low activities, low energy, or low hazard radioactive materials that are confined to a relatively small area
• Most spills that could occur in the lab would be minor and should be cleaned up by lab personnel
ASAP
• Use the general spill clean-up procedure and common sense
• You do not need to notify the RSO in the event of a minor spill

• An intermediate spill is one that involves larger quantities of radioactive material spread over a larger area
• Intermediate spills could also involve small amounts of more hazardous radioactive materials such as higher energy emitters or volatile compounds
• A spill outside a restricted area may also be considered intermediate since controlling the area may be difficult
• Use the general spill clean-up procedure and common sense

• Wear gloves, lab coats, dosimetry, and other protective clothing
• Confine the contamination
• Prevent the spread of contamination
• Use a survey instrument to check yourself for contamination before leaving the area
• Pay special attention to hands and feet
• Restrict access to the spill area
• Inform others in the immediate area and post notice if necessary
• Contact the RSO (x6640) to report the situation

 Fire in radioactive areas:
 Notify Fire Department and RSO, clear the area of people. Remove any seriously wounded persons.
Keep your distance
 Theft of radioactive materials:
 Notify RSO (info is posted on lab door)
 State notification required
 Notify RSO if you suspect:
 Inhalation, ingestion or other intake of radioactive material
 Accidental release of radioactive material into the environment

• Inspections
 NY shall be afforded opportunity to inspect at all reasonable times
 Records shall be made available
 Inspector may consult with workers privately
 Worker may bring matters to inspector privately
 Workers can request inspection
• Must be in writing
• Name is not revealed

• Internal audits by Clarkson RSO are performed in all labs on campus
• Looking for same things as state inspector
 Security of radioactive materials - including
 waste
Surveys for loose contamination
 Proper procedures in use
 Postings, container labeling, use of protective clothing, dosimetry, survey meters, calibrations, records of surveys, sink disposal logs, solid waste container logs, etc.

 Report anything that looks out of the ordinary or if you are uncertain about what to do, where to go, requirements, exposures:
 Call the people on the emergency list
 Ask the Radiation Safety Officer (RSO)
 Elayna Mellas
 268-6640
 emellas@clarkson.edu

This training course has been adapted from slides provided by Steve Backurz, Radiation
Safety Officer of The University of New
Hampshire