Radiation Monitoring Flashcards

1
Q

Types of Monitoring

A

Personnel Monitoring

Area/Workplace Monitoring

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2
Q

Personnel Monitoring Devices

A

Film Badge Dosimeter
Thermoluminescent Dosimeter
Optically Stimulated Luminescence
Pocket Dosimeter

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3
Q

Purposes of personnel monitoring devices

A

Control of radiation exposure
Identifies high dose
Assessment of working practices

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4
Q

Commonly used to measure and record radiation exposure due to gamma rays, x-rays and beta particles

A

Film Badge Dosimeter

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5
Q

Film is packaged in a ____ preventing light, moisture or chemical vapors from affecting the film

A

Light proof, vapor proof envelope

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6
Q

Special film is used which is

A

Coated with two different emulsions

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7
Q

One side is coated with a ______ that is sensitive to low levels of exposure

A

Large grain, fast emulsion

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8
Q

Other side of the films is coated with a _____ that is less sensitive to exposure

A

Fine grain, slow emulsion

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9
Q

Film is contained inside a ____

A

Film holder or badge

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10
Q

Badge incorporates a ____ to determine the quality of the radiation

A

Series of filters

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11
Q

Causes of in accuracy (film badge dosimeter)

A

Effect of heat on film

Effect of dosage on the film but not received by the wearer

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12
Q

Advantages of film badge dosimeter

A

Provides a permanent record
Able to distinguished between different energies of photons
Measure doses due to different types of radiation
Accurate for exposures greater than 100 millirem

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13
Q

Disadvantages of film badge dosimeter

A

It must be developed and read by a processor (time consuming)
Prolonged heat exposure can affect the film
Exposures of less than 20 millirem of gamma radiation cannot be accurately measured

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14
Q

Film badges need to be ____ so that the dose they receive accurately represents the dose the wearer receives

A

Worn correctly

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15
Q

Whole body badges are worn on the body bet ____ , often on the _____

A

Neck and waist

Belt or shirt pocket

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16
Q

Are worn on a finger of the hand most likely to be exposed to ionizing radiation

A

Ring badges

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17
Q

Are often used instead of the film badge

A

Thermoluminescence Dosimeter

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18
Q

Worn for a period of time (usually 3 millirem or less) and then must be processed to determine the dose received

A

Thermoluminescence Dosimeter

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19
Q

TLD is a phosphor, such as

A
Lithium fluoride (LiF)
Calcium fluoride (CaF), in a solid crystal structure
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20
Q

TLDs can measure doses as low as

A

1 millirem

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21
Q

TLD have a precision of

A

Approx. 15% for low doses

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22
Q

Advantages of TLD

A

Its Linearity of response to dose
Its relative energy independence
Its sensitivity to low doses
It is also reusable

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23
Q

Disadvantages of TLD

A

No permanent record or re-readability is provided and an immediate, on the job readout is not possible

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24
Q

Means emitting light when heated

A

Thermoluminescent

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24
It is a process in which a pre-irradiated material when subjected to an appropriate optical stimulation, emits a light signal proportional to the absorbed dose
Optically Stimulated Luminescence (OSL)
25
The characteristic of the OSL material
Wavelength of the emitted light
26
OSL is thus analogous to TL process except that the stimulation is
Carried out optically rather than thermally
27
Is a property of the solid state material
Efficiency of OSL
28
OSL emission is highly influenced by the
Energy and the intensity of the stimulating optical beam
29
Is the simplest and the most straightforward OSL process in which a pre-irradiated material is stimulated by a light source of constant intensity...
Continuous wave optically stimulated luminescence
30
Is a process in which the OSL signal from pre-irradiated material is measured after a stimulation light is switch off ...
Delayed optically stimulated luminescence
31
Is a form of DOSL in which the luminescence is recorded intermittently following a stimulation by very short pulses with a frequency of about thousands of hertz
Pulsed optically stimulated luminescence
32
These are used to provide the wearer with an immediate reading of his or her exposure to X-rays and gamma rays
Pocket Dosimeter
33
They are commonly worn in the pocket
Pocket Dosimeter
34
The two types (Pocket Dosimeter) commonly used in industrial radiography are the
Direct Read Pocket Dosimeter | Digital Electronic Dosimeter
35
The dosimeter contains a small ionization chamber with a volume of approx. two milliliters
Direct Read Pocket Dosimeter
36
Inside the ionization chamber is a ____ and attached to this wire anode is a ____
Central wire anode | Metal coated quartz fiber
37
The amount of movement is
Directly proportional to the amount of ionization which occurs
38
The fiber is viewed on a
Translucent scale (which is graduated in units of exposure)
39
Advantages of Direct Read Pocket Dosimeter
Ability to provide the wearer an immediate reading of his or her radiation exposure It is reusable
40
Disadvantages of Direct Read Pocket Dosimeter
Limited range Inability to provide a permanent record Potential for discharging and reading loss due to dropping or bumping
41
These dosimeters record dose information and dose rate
Digital Electronic Dosimeter
42
The dosimeters (Digital Electronic Dosimeter) most often use
Geiger-Müller counters
43
The counter then displays the _____ and ___ in digital form
Accumulated exposure | Dose rate
44
Some Digital Electronic Dosimeter include an
Audible alarm feature which emits an audible signal or chirp with each recorded increment of exposure
45
Workplace/Area Monitoring Instruments
Ionization chambers Proportional counters GM-tubes Scintillation detectors
46
Choice of Monitoring Instrument depends on
High or low levels Particles or photons Energy of photons Required accuracy
47
B - emitters
GM - tube | Proportional counters
48
Y-emitter (
GM-tube Proportional counter Nal(Tl) scintillation detector
49
Y-emitter (high energy)
Proportional counter | Nal(Tl) scintillation detector
50
Simplest of all gas-filled radiation detectors an is widely used for detection and measurement of certain types of ionizing radiation, X-rays and gamma rays and beta particles
Ionization chamber
51
The essential components of the ionization chamber are
Its two collecting electrodes: anode and cathode
52
The potential difference between the anode and cathode is often in the
100 to 500 volt range
53
Most commonly used for quantifying alpha and beta activity, they are also used for neutron detection
Proportional counters
54
Pulses produce by a proportional counter are
Larger than those produced by an ion chamber
55
Usually serves as the cathode in a proportional chamber
Cylinder
56
Serves as the anode in a proportional chamber
Fine metal wire (stretched along the axis of the cylinder)
57
Occurs near the anode at a distance comparable to the wire's diameter
Gas amplification
58
Are filled with an inert gas
Proportional counters
59
An instrument used for measuring ionizing radiation such as alpha particles, beta particles and gamma rays using the ionization effect produced in a Geiger-Muller tube
Geiger counter
60
Used to detect presence of low level radioactive particles and rays (
Geiger counter