RADIATION SAFETY QUESTION ANSWERS NDT CSWIP COURSE

Keywords for this article are RADIATION SAFETY QUESTION ANSWERS NDT CSWIP COURSE. radiation protection materials. radiation safety officer. radiation hazards and protection.

RADIATION SAFETY QUESTION ANSWERS NDT CSWIP COURSE

Several isotopes of elements such as hydrogen and carbon exist in nature. The isotopes of any given element differ only in terms of:

• the number of protons in the nucleus
• the number of alpha particles in the nucleus
• the number of neutrons in the nucleus
• chemical properties

The difference between x-rays and gamma rays of equal photon energy is:

• the wavelength of the gamma rays is shorter
• x-rays originate from an x-ray tube whilst gamma rays originate from a radioactive material
• the gamma rays are more hazardous to health
• the gamma rays have a higher velocity than the x-rays

If an ytterbium 169 has a half life of 32 days and the original source activity is 5 Ci, what will the source activity be 96 days later?

• 5 Ci
• 25 Ci
• 625 Ci
• 3125 Ci

The type of radiation that has a quality factor of 20 is:

• gamma radiation
• beta particles
• alpha particles
• x-radiation

 

When a radiation incident occurs, such as a gamma ray source becoming jammed in the delivery tube the most sensible way to proceed is to:

 

• monitor the area until the safety officer arrives
• after first of all securing the situation – if possible covering the source with bags of lead shot, adjusting safety barriers etc – make a plan of the actions that will be needed to make the source safe
• bury the equipment under several meters of earth
• call the fire brigade

 

Which isotope has a half life of 5.3 years?

 

• cobalt 59
• cobalt 60
• cobalt 62
• cobalt 70

Exposure to ionising radiation can have “genetic effects”. Such effects are best described as:

• those which can appear in the offspring of the person exposed to radiation
• effects such as headaches and diarrhoea which occur soon after an acute exposure to ionising radiation
• effects such as cancer which may not appear in the subject until some years after exposure to ionising radiation
• none of the above

 

The law that can be stated as: is called:

• the Bunsen Roscoe reciprocity law
• the inverse square law
• the build-up law
• Hooke’s law

 

The proportion of scattered radiation increases as:

• the photon energy of the primary beam decreases
• the photon energy of the primary beam increases
• the intensity of the primary radiation decreases
• the intensity of the primary radiation increases

 

Gamma ray equipment including wind-outs and projection tubes should be checked for leakage of fissile material on a regular basis; records of such checks should be maintained on file. The type of radiation monitor that is usually used for such checks is a:

• Geiger counter
• scintillation counter
• proportional counter
• ionisation chamber

An alpha particle is sometimes referred to as:

• an electron
• a helium nucleus
• a proton
• an electron – positron pair

 

Under the ionising radiation regulations the category of persons which has an annual dose limitation of 20 mSv is:

• trainees
• classified persons
• radiation protection advisers
• the general public

One important factor concerning the warning signals used when performing radiography on site is that:

• a combination of audible and visible signals should be used
• audible and visible signals should be used both before and during exposure
• the warning signal signifying “radiation exposure imminent” and the warning signal signifying “radiation exposure in progress” should be different
• an audible warning of at least 120 decibels is required prior to exposure

 

If the dose rate at 10 m from a source of radiation is 20 mSv/h the distance from the source at which the dose rate falls to 7.5 mSv/h will be:

• 4 m
• 3 m
• 9 m
• 8 m

 

The term used to describe a large dose of ionising radiation received in a relatively short period is:

• an acute exposure
• a somatic exposure
• a genetic exposure
• a brief exposure

 

One advantage of the Geiger Muller tube is that:

• its volume is relatively small. This makes it useful for locating leakage paths in radiation bay shielding.
• it operates at a low electrical voltage. Typically 12 V.
• it can distinguish between high energy and low energy x-rays
• it is exceptionally sensitive to alpha radiation

The device used in gamma radiography to restrict the size of the radiation beam, thus improving safety and reducing scatter problems is called a:

• focusing cup
• collimator
• mask
• diaphragm

A source of cosmic radiation is:

• the sun
• the earth
• iridium 192
• californium 257

Devices which record total radiation dose over a period include TLD badges, film badges and:

• scintillation counters
• electronic integrating personal dosimeters
• Geiger counters
• both (b) and (c)

In order to obtain a reading of radiation dose from a TLD badge the badge must be:

• heated
• exposed to UV-A radiation
• placed in a powerful magnetic field
• placed in a high voltage electric field

Concerning the emission of gamma rays which of the following is true?

• All radioisotopes are gamma emitters
• Some radioisotopes emit gamma rays and no other type of ionising radiation
• Some radioisotopes emit gamma as a by-product of alpha or beta emission
• Gamma rays are emitted only by man-made radioisotopes

Keywords for this article are RADIATION SAFETY QUESTION ANSWERS NDT CSWIP COURSE. radiation protection materials. radiation safety officer. radiation hazards and protection.

Factors that affect the half life of a radioactive isotope include:

• the source activity
• storage conditions
• the source size
• none of the above

The function of the metal filters in a film badge holder is to:

• discriminate between different photon energies of x and gamma radiation
• extend the measuring range of the badge
• both (a) and (b)
• none of the abov

Sources of ionising radiation include:

• the sun
• iridium 192
• granite
• all of the above

 

 

Which of the following types of radiation is ionising?

• alpha
• beta
• gamma
• all of the above

 

When an alpha particle is emitted the atomic number changes by:

• plus 2
• minus 2
• plus 4
• minus 4

How many becquerels are there in a gigabecquerel?

• 10,000
• 100,000
• 1,000,000
• 1,000,000,000

How many gigabecquerels are there in a curie?

• 7
• 37
• 370
• 3700

In a conventional x-ray tube electrons are produced by:

• the anode
• the cathode
• the target
• the window

The intensity of gamma rays at distance ‘D’ from a radioisotope is proportional to:

• 1/D²
• the source strength and 1/D²
• the source strength
• the source strength and D²

The material which in general provides the best and most economic engineering solution to the problem of shielding a radiation bay used for cobalt 60 gamma rays is:

• steel
• concrete
• brass
• lead

The 3 most important scattering processes in industrial radiography are:

• the photoelectric effect, Compton scattering & pair production
• incoherent scattering, Compton scattering & pair production
• the photoelectric effect, Compton scattering & Rayleigh scattering
• coherent scattering, incoherent scattering & pair production

The distance from a 7 Ci iridium 192 source (output 4.8 mSv/h/Ci at 1 metre) at which the dose rate falls to 7.5 mSv/h is:

• 45 m
• 93 m
• 00 m
• 77 m

 

If the unshielded dose rate of an iridium 192 source is 240 mSv/h at 25 m from the source what thickness of concrete shielding is required to reduce the dose rate at the same distance to 7.5 mSv/h if the half value thickness of concrete for iridium 192 is 42 mm?

• 84 mm
• 126 mm
• 168 mm
• 210 mm

The distance from a 0.7 Ci cobalt 60 source (output 13 mSv/h/Ci at 1 metre) at which the dose rate falls to 7.5 mSv/h is:

• 83 m
• 50 m
• 55 m
• 26 m

A body part which is particularly sensitive to exposure to ionising radiation is the:

• heart
• intestine
• hand
• brain

The output of iridium 192 is 4.8 mSv/h/Ci at one metre. At what distance from an unshielded 15 Ci iridium 192 source does the dose rate fall to 7.5 mSv/h?

• 30 m
• 81 m
• 47 m
• 98 m

The output of selenium 75 is 1.8 mSv/h/Ci at one metre. At what distance from an unshielded 15 Ci selenium 75 source does the dose rate fall to 7.5 mSv/h?

• 77 m
• 33 m
• 67 m
• 00 m

If the unshielded dose rate of a cobalt 60 source is 7.5 mSv/h at 40 m from the source what thickness of concrete shielding is required to reduce the dose rate at the same distance to 7.5 mSv/h if the tenth value thickness of concrete for cobalt 60 is 208 mm?

• 208 mm
• 416 mm
• 624 mm
• 832 mm

If the unshielded dose rate of a selenium 75 source is 120 mSv/h at 25 m from the source what thickness of concrete shielding is required to reduce the dose rate at the same distance to 7.5 mSv/h if the half value thickness of concrete for iridium 192 is 14 mm?

• 14 mm
• 28 mm
• 42 mm
• 56 mm

 

 

ANSWERS OF ABOVE QUESTIONS
Question	Answer	Question	Answer	Question	Answer	Question	Answer	Question	Answer	Question	Answer	Question	Answer
1	C	7	A	13	C	19	B	25	D	31	B	37	D
2	B	8	B	14	A	20	A	26	B	32	A	38	D
3	C	9	A	15	A	21	C	27	D	33	B	39	C
4	C	10	B	16	A	22	D	28	B	34	D	40	D
5	B	11	B	17	B	23	C	29	B	35	A
6	B	12	B	18	A	24	D	30	B	36	B

 

Keywords for this article are RADIATION SAFETY QUESTION ANSWERS NDT CSWIP COURSE. radiation protection materials. radiation safety officer. radiation hazards and protection.