Cedo Module Q Flashcards
Cedo cinde course
Five types of radiation monitoring devices
1- survey meter 2- direct reading dosimeter (drd) 3- thermoluminescent dosimeter (tld) 4- optically stimulated luminescence dosimeter (osl) 5- Alarming dosimeter
Survey meter must measure how many sieverts and what are the requirements
20 micro siverts/hour to 100 million siverts/hour. It must have a battery check function and be calibrated within the last 12 months.
Advantages and disadvantages Advantages to the direct reading dosimeter
Advantages: robust and low maintenance, small and clips clothing (pen shaped), weather proof, easily read by user
Disadvantages: limit rang usually less 5 milli sieverts, no permanent record, it can give false readings if dropped.
When did the use of the thermoluminescent dosimeter begin and when did it start phasing out.
It’s been used since 1976 and phased out in 2009
How does the thermoluminescent dosimeter work
It uses lithium fluoride chip which is used to store electrons displaced by radiation. The chips are read at the national dosimtry service
How does the optically stimulated luminescence dosimeter work. when was it put in use
It started in 2009. It contains sensitive elements that absorbed radiation and store some of the energy in the form of excited electrons. When received at the national dosimetry service. Sensitive elements are stimulated using light emitting diodes.
Equation for finding number of neutrons
Mass number(A) minus Atomic number(Z)= number of Neutrons(N)
Units for activity are?
Curi(Ci) and becquerel(Bq)
Specific activity is measured in?
Curi’s (Ci) per gram or Becquerel (Bq) per gram
What does an atom consist of
A nucleus consisting of protons(+) and neutrons and orbiting electrons(-1)
What does one curi (Ci) equally in becquerel (Bq)
1 (Ci)= 37 giga (Bq)
What is characteristic intensity and what is it measured by
It is measured by Reontgens per hour. Old system is measured by milli Rankin per hour@ 1 meter. New SI system milli siverts per hour@ 1 meter.
Equation for intensity
Intensity= Source Activity× Characteristic Intensity( see table 1)
What is radiation absorbed dose measured in
In the previous system units are measured in RAD (radiation absorbed dose) in the SI system its measured in Gray (Gy)
What is the conversion from RAD to Gray
1 Rad= 10 milli Gy
1 Gray= 100 Rads
What is the penetration capability for each form of radio active decay
1) Alpha rays- stop at paper
2) Beta ray’s- stop at thin board such as aluminum
3) Gamma and x rays- stop at thick board such as lead
4) Neutron rays- Stop at water concrete
How are industrial isotopes created
By placing elements in a nuclear reactor they gain one additional neutron. They become unstable and start the decay process releasing radiation.
What is the units for does equivalent
The previous system it was Reontgen equivalent man (REM). In the SI system it is referred to as Sieverts (Sv).
What is the Equation for Dose Equivalent and conversion
REM= Rad×QF
Sievert= Gray×QF
1 sievert= 100 REM
What is half life?
Half life is the time taken by specific isotope for the activity to decay to one Half its original value.
What’s is the half life for iridium 192, cobalt 60, and selenium 75
Iridium 192- 74 days
Cobalt 60- 5.3 years
Selenium 75- 120 days
What is the equation for determining half life and remaining activity
A2= A1÷2 to the power of n
A1- original activity
A2- new activity
N- number of half-lives
When must an Alarming dosimeter be used. when should it alarm at and how often should it be calibrated
Must be used when using gamma radiation. It must alarm at 5 milli sieverts per hour or when the total dose reaches 2 milli sieverts. It must be calibrated within 12 months.
When do you use the log symbol for calculating half life’s
When you have both values of activity before and after the decay and you want to find how many half life’s used. Simply sub a2 for n. Find the answer and log it by 2
What are the clarifications of Biological Effects
Acute Effects: Those appearing within minutes, day’s or weeks
Long term (chronic): Those appearing years or generations later
Somatic Effects: refers to radiation injury to the person involved but not the reproductive cells
Genetic Effects: Refers to radiation exposure that results in some chromosome damage, thus effecting future generations
What is the Latent period and Recovery period?
Latent period: the period of time following the radiation event until the time at which the effects of the radiation become visible.
Recovery: Recovery can and does take place to a certain extent. Particularly true with Acute Effects. There is always residual damage from which no Recovery takes place.
What are radio responsive tissue that can be effected by radiation
Blood forming organs
See organs
Other tissue (liver, lens of the eye)
What are radioresistant tissue’s that can’t be effected by radiation?
Connective tissue
Muscle, fat, bones
Nerves, brain
Is there a unit of measure for biological effects
No
What will the effects of 200 mill sieverts life time exposure of gamma radiography have on the shortening of life.
With a great deal of care little to no effects
What will a whole body effect be of 0-250 millisieverts
No obvious injury
What will a whole body effect of 250-500 millisieverts be
Possible temporary blood changes, but no serious injury
What will the effects be of a 500-1000 milli sievert ( 1sievert). Whole body does be
Blood and cell changes, some injury no disability
What will a whole body dose of 1-2 sievert effects be
Injury possible disability
What willa whole body dose of 2-4 sieverts be
Injury and disability certain, death possible
What will the effects of a whole body dose of 5 sieverts be
Fatal to 50% of people within 30 days
What will the effects of a whole body dose of 10 sieverts be
Fatal to all
What does A.L.A.R.A men and how can it be achieved.
The meaning of A.L.A.R.A is keeping radiation exposure to as low as reasonably possible. Through controlling time, distance, shielding
What is the equation for calculating dose equivalent or dose
Dose= Intensity× time (which you have to divide in to 1 hour eg 12 min÷1 hour)
When is the inverse square law used
If we are interested in a dose at a distance other than 1 meter.
What is the inverse square law
I1÷ I2= D2(squared)÷ D1(squares)
i1- is the initial intensity
D1- the distance which that is known
I2- the intensity at a different distance
D2- the distance from the source to where we want to know that second intensity
What is the equation for half value and tenth value.
Hvl: i2= i1÷2 (power of n)
Tvl: i2= i1÷10 (power of n)
i2: the new intensity after the shielding
i1: the initial intensity before the shielding
N: number of half value layers that exists (must divide thickness into tvl or hvl)
When do you use log function when dealing with hvl and tvl
When both intensity are given and the thickness needs to be found (use processes of substitution swap i2 for 10n and then log the answer with 10 or 2 logged )
Where is the collimator located and what is usually composed of.
Located at the end of the source guide tube usually made of tungsten, depleted uranium or lead
Can the collimator be used for shielding in an emergency source recovery situation.
No
When the source is in fully shielded position.What should the outside of the exposure device never exceed.
2 milli sieverts
During exposure what should the survey meter not exceed.
.1 milli sievert per hour
When is the go no go Guage used
When checking the drive cable and pig tail for wear
When is the radiation barrier limit established. (Magic number)
The barrier limit is established at 0.1 m sv/hour some companies have lowered it to 0.025 milli sieverts/hour.
What is the the exposure limit around the storage area of the exposure device. (Magic number)
O.25 milli sieverts per hour
What should the surface of the device not exceed in. (Magic number)
2 millisieverts before use or upon installation of new source.
What should the Survey meter be capable of measuring and what must it indicate. (Magic number)
Between 20 micro sieverts and 100 milli sieverts.
It must indicate power level of its battery and that it’s sufficient for its operation.
When should a survey meter be calibrated. (Magic number)
Must be calibrated once every 12 months
At what reading should you stop work and investigate. When using the direct reading dosimeter. (Magic number)
2 millisieverts during your shift
When should you do a leak test and at what reading should it be put out of service. (Magic number)
A leak test must be conducted once per year and upon installation of new source. If the results are found to be 200 becqureal or higher. The device must be with drawn.
How long do tongs have to be. what is the shielding factor of the emergency tunnel to be used. (Magic numbers)
Tongs must be a a minimum of 1.5 meters and emergency tunnels must have a shielding factor of 100.
What is the characteristics of particulate radiation
It has mass and energy and its subatomic
How many hours of on the job training is required before attempting the final practice exam
320
How does an isotope try to achieve stability
Giving off particulate radiation (alpha and beta particles). Give off gamma radiation. Capture electrons
What is ionization
Process of adding or removing electrons from an atom
What was quality factor formerly know as
R.B.E relative Biological Effectiveness
When using external sealed source guide. What emergency equipment must you have present (Magic number)
Emergency tunnel shielding factor of 100, tools that can sever the tube and cable from the exposure device (bolt cutters), tong with a shaft of at least 1.5 m, audible dosimeter, wear on the trunk of the body dosimeter that suitable for recording any dose of radiation the person may encounter (must emit audible alarm)
What are the source tag requirements (Magic number)
Every licensee who possesses, uses or produces an exposure device shall have. A source tag is made from steel or brass or steel. Affixed securely by means of metal fastener. Durable brass/steel tag that is visible and legibly inscribed with name, quantity in becuerels, date of measurement of that quantity and form of the nuclear substance contained in the exposure device.
What is the inventory checklist you must do to prepare for a job.
1) survey meter battery level
2) audible alarms (beepers) battery levels
3) calibrated stickers for survey meters
4) calibrated stickers for audible alarms (beepers)
5) calibrated stickers for drd
6) 1.5 meter tongs
7) emergency tunnel
8) bolt cutters
9) go-no-go gauge testers
10) decay chart
11) source ID tag
Everyone who operates an exposure device shall have available
A radiation survey meter that is capable of measuring a dose rate of gamma radiation between 20 micro sieverts to 100 mili sieverts. Indicate power levels of its battery and that its sufficient for its operation. We also need verify its calibration stickers that its be calibrated in the last 12 months.
What is the legislation that regulats the transportation of nuclear substances. What are the packaging labeled as.
It is regulated by the packaging and transport of nuclear substances regulations. Packaging is labeled as Type A, Type B, Type C.
What are most exposure device’s labeled at as far as transportation. What do they require.
Most radiographic exposure devices are designed as type B and require the approval of the Canadian nuclear safety commission.
What should the certification received to transport source describe.
Device and it’s content limits
Can foreign manufacturers devices be used in Canada
Yes in the form of a Canadian endorsement to the foreign approval certificate.
Shippers responsibility when transporting exposure device.
Shipper is responsible for proper packaging and that the source capsule is locked in safe position and the key is removed.
What is the difference between type A and Type B logo for transportation
Type A devices contain lesser amounts of radioactive material than Type B.
When transporting radioactive material the vehicle must have placard withe diamond shaped radioactive sign. True or false
True
When not transporting radioactive material the placard can stay on. True or false
False. Must be removed or covered
Preventing and dealing withe emergencies begins
The moment you pick up the exposure device. Ending with when it is returned to safe storage.
Steps taken during emergency
1) stop and think
2) verify the source location
3) establish barriers
4) advise radiation safety officer ( it is his/her responsibility for the rereval plan and the actions to be taken)
If there is no sudden increase during retraction you can likely conclude
The source is at the end of the guide tube (in the collimator)
If there is a sudden increase and the levels do not drop off during retraction you can likely conclude
The source is stuck in the guide tube
If the levels increase and then drop off to the shielded levels at the exposure device. But not at the guide tube end during retraction. You can likely conclude
The source is in the device but not in the fully shielded position.
The source retrieval plan and the actions taken are the responsibility of
The RSO
Minimum mandatory emergency equipment required all times
Emergency tunnel, cutters (bolt cutters), long handle tongs minimum of 1.5 meters long
What is the certified exposure personnel certification guide and when was it published
It is csa PCP-09 and it was published March 2015
In a neutral Adam existing by its self the number of electrons are equal to the number of……….
Protons
How much disintegration per second is one curi
1 ci= 3.7×10 (to the 10 power)
Three types of survey meters
Ion chamber (most common)
Geiger muller counter
Proportional counter
Factors that influence extent of Biological damage
1- total amount of radiation absorbed 2- type of radiation 3- rate of absorption 4- area exposed 5- individual variability 6- relative sensitivity of cells and tissue
Two types of radiation and their characteristics
Particulate: it has mass and energy and it is subatomic
Electromagnetic: no rest mass. It’s pure energy and travels at the speed of light. Two examples are x-ray and gamma ray’s.
What are the types of ionizing radiation
Ultraviolet, x-rays, gamma ray’s
No ionizing radiation includes
Radio waves
Micro waves
Infared Radiation
How does and unstable isotope achieve a suitable balance
Give off particulate radiation
Give off gamma radiation
Capture electrons
3 types of particulate radiation
Alpha particle
Beta particle
Neutron rays
What is the characteristics intensity’s for selenium 75, iridium 192, cobalt 60
Selenium 75- 200 mR/hr@1 m, 0.05 msv/hr@1m
Iridium 192- 550 mR/hr@1m, 0.15 mSv/hr@1m
Cobalt 60- 1350 mR/hr@1m, 0.36 mSv/hr@1m
What is QF for x-ray, gamma rays, electrons, beta particles, neutrons energy less and greater than 10 kev, protons, alpha particles, fission fragments, recoil nuclei
X-Ray, gamma rays– 1
Electrons, beta particles
Neutrons (energy less than 10 KeV)- 3
Neutrons (energy greater than 10 KeV)- 10
Protons- 5
Alpha particles- 20
Fission fragments, recoil nuclei- 20
What is the half value layer for uranium, tungsten, lead, steel, concrete when using iridium 192 and cobalt 60
Uranium/iridium: Hvl 2.8 mm, Tvl 9.3 mm
Uranium/cobalt: Hvl 6.9 mm, Tvl 22.9
Tungsten/iridium: Hvl 3.3 mm, Tvl 10.9 mm
Tungsten/cobalt: Hvl 7.9 mm, Tvl 26.2 mm
Lead/iridium: Hvl 4.8 mm, Tvl 16.2 mm
Lead/cobalt: Hvl 12.4 mm, Tvl 41.1 mm
Steel/iridium: Hvl 8.7 mm, Tvl 29.0 mm
Steel/cobalt: Hvl 22.0 mm, Tvl 73.6 mm
Concrete/iridium: Hvl 48.2 mm, Tvl 157.4 mm
Concrete/cobalt: Hvl 68.5 mm, Tvl 228.6 mm
What are property’s of gamma radiation
Travels in straight lines
Not affected by electric or magnetic fields
Cannot be focused
Affects photographic emulsion
Can damage or kill living cells
Cannot be detected by normal human senses
