CEDO - Cinde Manual Flashcards
1
Q
The monitoring of Thermoluminescent (TLD) or Optically Stimulated Luminescence (OSL) dosimeter badges are monitored by
A
NDR/NDS Health and Welfare Canada
2
Q
How often are TLD/OSL badges issued
A
Bi-Monthly
3
Q
The report sheet for radiation doses received show the
A
Previous 2 week period of the personal radiation dose received and the life time total for the individual
4
Q
Who discovered X-Rays
A
Wilhelm Roentgen 1895
5
Q
Who discovered penetrating radiation
A
Pierre and Marie Curie
6
Q
Who discovered natural radioactivity
A
Henri Becquerel 1896
7
Q
Radiation can be either
A
High speed particles or energy travelling in Electromagnetic Waves
8
Q
What is the main difference between the different forms of electromagnetic energy
A
Their frequency and wavelength
9
Q
The primary part of an Atom
A
Proton: heavy +1 charge
Neutron: heavy, no electrical charge
Electron: light, orbit in shells around nucleus, -1 charge
10
Q
The shells of an electron are lettered ______?
A
K-Q
11
Q
Atomic number is the number of protons located in the nucleus and is represented by what letter
A
Z
12
Q
Mass Number are the total protons and neutrons located in the nucleus and is represented by what letter
A
A
13
Q
To determine the number of neutrons in a nucleus use the formula
A
N = A-Z
Atomic number - Mass Number
= Neutrons
14
Q
What is an Isotope
A
Atoms of the same element but with different mass numbers, with the chemical characteristics remaining the same.
15
Q
Why are some Isotopes radioactive or unstable
A
Some isotopes have too many or too few neutrons in the nucleus and attempt to reach a stable ratio
16
Q
How does an isotope attempt to reach a stable ratio of neutrons and protons
A
Emitting either alpha or beta particles of either sign, capture orbital electrons, or emit gamma radiation
17
Q
What is a X Radiation
A
Transfer of energy between the high speed interaction of electrons and a dense target material
Can be controlled
18
Q
What is Gamma Radiation
A
Emitted from an unstable atom and cannot be controlled
19
Q
Artificial Production of radioisotope are produced in three ways
A
Neutron activation,
Fission product separation,
Charged particle production
20
Q
What is an Ion
A
Any atom or molecule which has a resultant electric charge due to loss or gain of a valence electron
(electrons that orbit near the outer shell of the atom)
21
Q
When almost completely ionized gases form a fourth state of matter known as
A
plasma
22
Q
Free electrons are sometimes loosely classified as
A
Negative ions
23
Q
How are Ion Pairs formed
A
A neutral atom or molecule by the action of radiation or any other agency that supplies energy.
Consisting of a positive and negative ion, having charges of the same magnitude.
24
Q
What is the process of Ionization
A
Adding electrons to or removing electrons from atoms or molecules
X and gamma radiation are ionizing radiation
25
Ionizing action of x-rays produce what effects
Causes certain materials to fluoresce,
Produce chemical effects,
Cause biological effects such as the deterioration or destruction of living cells,
When a gas is bombarded by radiation it ionizes and becomes an electrical conductor ( principle of ionization sectors)
26
What are the properties of x and gamma radiation
They travel in straight lines ( rectilinear propagation)
They are not effected by electrical or magnetic fields
They cannot he focused
They will affect photographic emulsions (chemical)
They can damage or even kill living cells, produce burns and changes to the blood or blood forming organs ( physiological)
They cannot be detected by normal human senses
27
What is Radioactivity
Unstable atoms are radioactive. The nuclei change or decay by spitting out radiation in the form of particles or electromagnetic waves
Radioactivity is an element being unstable to due to excess energy
28
What is an Alpha Particle (a)
Large and slow moving particles. Causes many ionization along a short path and it’s energy is stopped in a short distance
Can not penetrate the dead layer of skin or piece of paper
Hazard when ingested or inhaled
29
What is a Beta Particle (B)
Light and high velocity, nuclear origin with an electrical charge of -1
Deflected and scattered
Absorbed by few mm’s of aluminum
Travel several hundred cm’s in air before losing energy
30
What is Neutron Radiation
Same mass as a proton but no electrical charge
Rare but very penetrating
Shielding is water or hydrogenous material
31
What are Gamma Rays
Electromagnetic radiation with very high energy
Can travel up to 100M in air or further and is highly penetrating and ionizing
Most hazardous
Stopped by Lead
32
What is an industrial Isotope
Radioactive material ( radioisotopes) contained in a stainless steel capsule and used for NDT
Co60
IR 192
Se75
33
What are the parts of the sealed source assembly (Pig Tail)
Female portion of connector
Stop Ball
Flexible Steel Cable
Stainless steel capsule containing radioactive material
34
What are the organizations that selects and defines units and quantities of radiation
International Commission on Radiological Units and Measurements in conjunction with International Commission of Radiological Protection
35
One gram of radium undergoes _______ transformations of disintegration’s per second
Use Curie
3.7 x 10(10) or 37,000,000,000
36
How is the activity of a radioactive isotope determined
By the number of atoms of the material which will decay (disintegrate) in a given period of time
37
In the SI units the ___ is the unit of radioactivity
```
Becquerel
One Bq is equal to 1 disintegration per second (dps)
1MBq - 27 microcuries
1GBq - 27 millicuries
37GBq - 1 curie
1 TBq - 27 curies
```
38
What is Specific Activity
The degree of concentration of radioactive material within the gamma source
39
How is Specific Activity measured
OLD - curies per gram
NEW - Becquerels per gram
40
Why is Specific Activity important to a radiographer
A high specific activity will yield sharper radiographs
41
What is Characteristic intensity
A disintegration in a radioactive source does not necessarily result in the same amount of radiation emission
42
How is Characteristic a intensity a measured
Roentgens per hour at one metre
Measure of radiation emission of a given period of time
R/hr @1m
43
What are the Becquerel measurements
```
1 Bq - 1 dps
1kBq - 10(3)
1MBq - 10(6)
1 GBq - 10(9)
1 TBq - 10(12)
```
44
Characteristic Intensity a measurement
```
OLD
IR192
550mR/hr @ 1 metre
Co60
1350mR/h @ 1 metre
Se75
200mT/hr @ 1 metre
```
```
NEW
IR192
.15 mSv/hr @ 1 metre
Co60
.36mSv/hr @ 1 metre
Se75
.06 mSv/hr @ 1 metre
```
45
What is Exposure
The quantity of radiation incident upon an object
The quantity of electric charge produced per unit of air mass
OLD - Roentgens
NEW coulomb/kilogram (c/kg)
46
Why is Radiation Intensity
Energy which is absorbed by any matter placed in a radiation beam
47
How is Radiation Intensity measured
Old - R/hr
| New Sv/hr
48
What is Radiation Intensity also known as
Dose Rate
49
What does Radiation Intensity (Dose Rate) not take into account
Information on the type of particles or degree of damage
50
What is the Radiation Absorbed Dose
Quantity for considering radiation damage to living tissue
| 1R = 100ergs of energy
51
What is the measurement for Radiation Absorbed Dose
OLD - RAD
NEW - GRAY (Gy)
1 RAD = 10mGy
1 Gy = 100 RAD
52
What is Quality Factor ( Relative Biological Effectiveness RBE)
Reflect the relative harmfulness of the four types of radiation
53
What are the harmfulness rating for Quality Factor/ RBE
```
Y, B and Xrays - 1
Thermal Neutrons - 3
Fast n and protons - 10
Heavy and recoil nuclei - 20
Alpha Particles - 20
```
54
What is Roentgen Equivalent Man or Dose Equivalent
CGS unit used equivalent dose,effective dose and committed dose which measure the relative biological effects in man
55
What is the measurement of REM
1Sv = 100 rem
REM = RAD x QF ( RBE)
56
What is Half Life
Length of time required for the activity of the radioisotope to decay to one half and its initial activity
57
What are the half life values for IR192, Co60, Se75
IR 192 74 days
Co60 5.3 years
Se 75 120 days
58
What formula do you use to find the half life value
A2 = A1/2(n)
A1 original Activity
A2 Nee activity
N number of half lives
59
What is the most important piece of equipment for a radiographer
Survey Meter
60
What are the three most common types of Survey Meters
Ion Chamber
Geiger Muller CounteR
Proportional Counter
61
How to Survey Meters work
The negative charge atoms are attracted to a positively charge plate. The positive charges are attracted to a negative plate and the movement between the two creates an electrical current which is displayed on meter
62
What are Direct Reading Dosimeters (DRD)
A personal radiation monitoring device with an ionization chamber and displays the absorbed dose
63
Advantage of a DRD
Robust and requires low maintenance
Small and easily clipped to clothing
Weatherproof and does not need to be protected from weather
Can be read at any time by user and gives dose immediately after exposure
64
Disadvantages of DRD
Limited range
Does not provide permanent record
False reading if damaged
65
Procedure for wearing and using DRD
```
Charge before work
Record reading before work
Clip to trunk of body
Read dose throughout day
Record dose at end of work
```
66
What is a Thermoluminescent Dosimeter (TLD)
Monitor both whole body and skin dose of exposure
Consists on inner plaque, when gamma rays strike the lithium fluoride strips some electrons are displaced and can be read later
67
What is the Optically Stimulated Luminescence Dosimeter ( OSL)
Aluminium oxide stripe with laser light causing it to luminesce in proportion to amount of radiation exposure
Can be used multiple times
68
What dose can the OSL detect
X and Y ray 10mSv to 10Sv
| Beta Particle 100mSv to 10Sv
69
Objectives of Dosimetry Service
Estimate doses received by workers in national database
Report to organizations individual doses
Draw attention to managers and government when a worker exceeds dose limit
70
Procedure for wearing a TLD or OSL
Clip to trunk of body
Do not expose to high temps or water
If you lose or damage TLD/OSL stop work until a replacement is received
Do not expose the plaque to fluorescent light or sunlight
71
Advantages of TLD/OSL
Sufficient range to measure background dose
Robust and does not require maintenance
Accumulates high dose
Provides permanent record
72
Disadvantages of TLD/OSL
Must be sent away to be read
| Delay in knowing dose received
73
What is a Personal Alarming Dosimeter
Must be worn at all times and will sound an alarm if high intensities are detected
Can prevent exposure if survey meter fails to warm you
Must never be replaced with survey meter
74
As CEDO you must control your own exposure as by doing
Use radiation safety procedures
Maintain and use gamma survey meter
Wear personal dosimeters when performing radiography work
75
What are the Health Effects of Radiation Exposure
Prompt (Acute) Health Effects
Days, weeks or months after exposure - radiation burns or sickness
Delayed (Somatic) Health Effects radiation injury to person involved but not reproductive cells
Long Term ( Chronic) Effects appear years or generations later
Genetic Effects exposure that results in some chromosome damage thus affecting future generations
Long term genetic effect can be caused by extremely low doses and occur independently of the actual intensity
76
What is the Latent Period
Following initial radiation event before the effects become visible
77
What is Recovery Period
Recovering to an extent of radiation damage; however residual damage where no recovery occurs
78
What are Radioresponsive Tissues
Blood forming Organ (bone marrow, spleen),
Sex Organs,
Other tissues liver, lens of eye
79
What are Radioresistant tissues
```
Connective tissues (tendons, ligaments),
Muscle,
Fat,
Bone,
Nerves, brain
```
80
Factors influencing extent of Biological Damage
```
Total amount of radiation absorbed
Type of radiation
Rate of absorption
Area exposed
Individual variability
Relative sensitivity of cells and tissue
```
81
Types of Effects of exposure
Injuries to superficial tissues ( burns)
General effects on the body ( blood and blood forming organs)
induction of malignant Tumors
Impaired fertility, cataracts, reduction of lifespan
Genetic effects
Early effect of a cute whole body exposure
82
What is photoelectric effect
Gamma ray collide head on with an orbital electron and absorbs the energy of the gamma ray driving the electron free of its orbit
83
What is Compton Effect
Collide head on with an electron but is not entirely absorbed the gamma energy and causes the electron to collide with other extrinsic creating a free electron and positively charged atoms
84
Most important characteristic of gamma radiation
The ability to ionize other atoms of material through which they pass
85
What is the purpose of dose limits received by a person is:
A dose of of ionizing radiation that, in the light of present knowledge, is not expected to cause appreciable bodily injury to a person at any time during their lifetime
86
No Licensee shall authorize a person to operate an exposure device that
Does not appear to be functioning normally
| Has a radiation intensity of more than 2mSv per hour on any part of its surface
87
What is a nuclear energy worker (NEW)
Defined by NSC
A person who is required in the course of the person business or occupation in connection with a nuclear substance or nuclear facility to perform duties in such circumstances that there is a reasonable probability that the person may receive a dose of radiation that is greater than the prescribed limits for the general public
88
What are the Maximum Permissible Dose Limits
NEW including pregnant NEW
1 year - 50mSv
5 year - 100mSv
Pregnant NEW Balance of pregnancy - 4mSv
Person who is not NEW one calendar year 1mSv
89
What are the permissible doses in an emergency
500mSv to the body
1000mSv to the skin
Does not apply to pregnant worker
90
CNSC state for any other person the weekly dose limit is
.1mSv weekly
| .5mSv yearly
91
Dose Limits for Organs
Lens of Eye
NEW - 1 year 150mSv
Any other person one calendar year - 15mSv
Skin
NEW - one year 500mSv
Any other person one calendar year - 50 mSv
Hand and Feet
NEW one year 500mSv
Any other person one calendar year - 50mSv
92
Three ways to lower your dose when doing radiography
Time: don’t stay near source or device longer than necessary
Distance: stay as far away from source and device as you can
Shielding: use shielding between yourself and the source
93
How to Calculate Intensity
Use survey meter
Or
Apply output factor to source activity
94
What is the formula for Dose as a function of time
Dose= Intensity x Time
Total minutes exposure divided by 60 mins
Total seconds divided by 3600
Then intensity x time
95
What is the the Intensity as a function of distance
Inverse Square Law
| By applying the law if you know the intensity at a given distance you can determine the intensity at any other distance
96
What is the formula for Intensity as A Function of Distance
I1/I2= D2(2)/D1(2)
97
What is Dose as a Function of Shielding
Using shielding material to reduce the intensity of radiation
98
Rank the most effective to least effective shielding material
```
Depleted Uranium
Tungsten
Lead
Steel
Concrete
```
99
What is a Collimator
Small pieces of lead, depleted uranium or tungsten that partially surrounds the source to absorb the radiation not directed towards the area of interest being radiographed
100
What are half value layers and tenth value layers
Half Value Layer: thickness of a specific absorbing material required to reduce the intensity by half
Tenth a value Layer: thickness of a specific absorbing material required to reduce the intensity by one tenth its original value
101
What is the formula to find Half Value and Tenth Value later
I2=I1/2(n)
Or I2=I1/10(n)
```
I2 -new Intensity
I1 - original intensity
2 Half value layer
10 tenth value layer
n - number of layers
```
102
What should the shielding factor of an emergency tunnel be
Minimum 100
103
Magic Numbers of Radiation Barrier
.1mSv/hr
Section 32(1)(j)
Nuclear Substance and Radiation Devices Regulations
104
Magic Number of Surface of Device
2mSv/hr before use or upon new installation of new source
Nuclear Substance and Radiation Devices Regulations 30(4)(b)
105
Magic Number of Storage Area
.025mSv/hr
106
Magic number of Survey Meter
Capable of measuring between 20uSv to 100mSv/hr
Nuclear Substance and Radiation Devices Regulations 31(1)(a)(i)
107
Magic number for Survey meter calibration
Once every 12 months
| Nuclear Facilities and Prescribed Equipment Regulations s.18(1)(a)
108
Magic number forNEW DRD reading
Exceed 2mSv during shift stop work and investigate
Nuclear Substance and Radiation Devices Regulations
109
Magic Number for Leak Test
Once per year or upon new source installation 200Bq or higher withdraw device from use Nuclear Substance and Radiation Devices Regulations 18(1)(3)
110
Magic Number for Long Handled tongs
Minimum 1.5 Metres Nuclear Substance and Radiation Devices Regulations31(1)(b)(iii)
111
Magic number for emergency tunnel
Minimum shielding factor of 100
Nuclear Substance and Radiation Devices Regulations 31(1)(f)(i)
112
Magic number for Audible Dosimeter
Alarms at 5mSv/hr or total dose reached 2mSv calibrated within 13 month period
Nuclear Substance and Radiation Devices Regulations 31(1)(f)(ii)
113
Magic number for Source tag
Made of steel or brass and contains name of source, quantity in Bqs , date of measurement
114
Which Act do Federal Regulations fall under
Nuclear Safety and Control Act
115
Where Provincial safety regulations are published
Ontario Gazette,
Ontario Minister of Labour X-Ray Safety Regulations
116
If ionization occurs in human blood cells and tissue it
Poses a serious health risk
117
What should you do in an emergency
Stop and think
Verify source location
Plan source retrieval
118
Who is responsible for administering CEDO exams
NRCan
119
What does the Canadian Nuclear Safety Commission. (CNSC) responsible for
To ensure the use of nuclear energy poses no risk to the health, safety, environment and national security, as well as control the import export of substances, equipment and technology
120
What changes the amount of radiation reaching the film causing darker area where more radiation penetration
Holes, cracks, impurities and other various flaws
121
Electrical Potential Energy forced which act between charged bodies
Electrons in outer shells have a higher energy than those closest to the nucleus
122
What is Background Radiation
Emitted from naturally occurring radioactive materials in the earth and from cosmic rays that bombard the earth from outer space
123
What is the Yellow Label III
Packages containing radioactive material where the dose rate exceeds 5uSv/hr but does not exceed 2mSv/hr. Index package is 10
124
What Class does radioactive material fall under when Transporting Dangerous Goods
Class 7, and 4 placards required on vehicle
125
When does the most serious radiation exposure occurrs
Worker fails to follow specific operating procedure,
Worker fails to use radiation detection equipment,
Remains next to or physically handle unshielded source,
Source falls into the hands of unauthorized person
126
What is Scattered Radiation
Occurs when beam intercepts an object causing the xrays to be scattered which can result in loss of contrast and definition
127
How can you control Scatter
Moving objects out of the way
128
What does ALARA stand for
At the Lowest Reasonably Achievable Level
129
What does the radiation effect depend on
The amount of energy and the type of radiation a person was exposed to
130
What are the Prompt Effects of Ionizing Radiation
0-250mSv no obvious injury
250-500mSv possible temporary blood changes, but no serious injury
500-1000mSv(1Sv) blood cell changes, some injury, no disability
1-2Sv injury, possible disability
2-4Sv injury and disability certain, death possible
5Sv fatal to 50% of people within 30 days
10Sv fatal to all people
131
What is the formula to determine intensity
Intensity at _____metre
=
Source strength x source output factor
132
What are the source output factor for IR192, Co60, and Se75
IR192 .15mSv/h @1m
Co60 .36mSv/h @ 1m
Se75 .05mSv/h @1m
(mSv/h per GBq
133
How does the “S” shaped tube prevent gamma radiation from escaping the device
Gamma radiation travels in a straight line and the “S” shape tube prevents it from escaping without first passing through the shielding material
134
What is the connection sequence of the device
1. Drive cable to camera
2. Collimator to source guide tube
3. Source guide tube to camera
135
What is Attenuation
Reduction in the intensity of radiation as it passes through any material for example through lead shielding
136
What is Contamination
The spreading of radioactive material which occurs when the source capsule is damaged and released its contents
137
What is the Crank Handle
Handle used to crank the source in and out in a cable operated exposure device
138
What is the decay constant
Numerical constant that express the rate at which radioactive materials decay
139
What is the Decay Curve
Graph showing the decreasing radioactivity of the source as time passes. Can also refer to the line or curve on the graph that indicated the activity
140
What is the Drive Cable (Control Cable)
Cable used to push out and retract the source in a cable operated exposure device. Usually operated with a crank or push pull mechanism
141
What is the Lock Box
Part of radiographic exposure device that contains the mechanism used to lock the source capsule assembly into its safe shielded position
142
What is the Source Guide Tube
A hollow tube which the radiographic source travels when it is moved out of and retracted back into its shielded position in the exposure device
