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A nuclear reactor produces neutrons that have energies distributed from less than 0.01 eV to greater than 20 MeV. For most neutron radiography, the thermal energy group is used. This group has energies:

a. below 0.01 eV

b. 0 to 0.3 eV.

c. 0.3 to 10 000 eV

d. 10 keV to 20 MeV

The primary radiation mechanism for darkening X-ray film when the direct radiography process is used employing gadolinium screens is:

a. alpha particles

b. electrons.

c. gamma rays

d. light emission

Neutron radiography is an excellent tool for determining:

a. the coating thickness of aluminum oxide on anodized aluminum

b. voids in thick steel castings

c. the integrity of thin plastic material within a lead housing.

d. voids in thick plastic sections

Which of the following materials is the greatest attenuator of thermal neutrons?

a. aluminum

b. copper

c. lithium.

d. iron

Thermal neutrons that are relatively free from higher energy components are obtained by allowing neutrons from the source (reactor, radioactive source, accelerator) to pass through moderating material. This material may be:

a. water

b. paraffin

c. graphite

d. all of the above.

The sample part may become radioactive as the result of neutron activation during the neutron exposure. As a general rule, the level of radioactivity will be:

a. high

b. very low.

c. dangerously high

d. none of the above

The absorption of neutrons in an object depends upon:

a. the neutron cross-section

b. the nuclides in the object

c. the object thickness

d. all of the above.

The energy of the neutrons in a neutron beam:

a. is the same for all neutron beams

b. does not affect the radiographic parameters

c. has no bearing on neutron absorption in the material to be radiographed

d. directly influences the choice of usable conversion screens.

directly influences the choice of usable conversion screens.

a. a flat neutron cross-section across all energies

b. a cross-section that peaks at thermal energies

c. a high thermal neutron cross-section that drops off rapidly at higher energies.

d. their highest neutron cross section at 1.4 eV

10.

Which of the following conversion screens has the longest half-life?

a. dysprosium.

b. indium

c. cadmium

d. gadolinium

11.

The unique and important properties of the neutron in neutron radiography come primarily from the fact that it is a nuclear particle that is electrically neutral. The lack of electric charge means that its electrostatic interaction with the atom’s electrons is:

a. almost complete

b. scattered

c. almost completely negligible.

d. such that the electrons and neutrons combine with each other

12.

The rare earth is frequently used in neutron radiography. An interesting feature of this family of elements is:

a. that they have nearly identical chemical properties and are, therefore, difficult to tell apart

b. that they make up about one-sixth of all naturally occurring elements, but the entire group occupies only one position in the Periodic Table

c. that they have large absorption cross sections for neutrons

d. all of the above.

13.

A thin sheet of gadolinium foil, in intimate contact with photographic film during neutron exposure, will increase film density because:

a. it fluoresces and emits visible light, which helps expose the film

b. it emits electrons that darken the film.

c. it absorbs the scattered radiation

d. it prevents back-scattered radiation from fogging the film

14.

For direct neutron radiography, precaution has to be taken to reduce the gamma-ray background of most sources as this tends to obscure the neutron radiograph. This may be done by:

a. using filtration of gamma rays.

b. increasing the source-to-film distance

c. both a and

d. neither a nor b

15.

The transfer exposure technique, sometimes called the indirect technique, uses neutron converters that have a reasonably long radioactive half-life. Which of the following would be a good candidate?

a. indium

b. dysprosium

c. both a and b.

d. neither a nor b

16.

Which of the following neutron radiography converter foils cannot be used for transfer or indirect radiography?

a. dysprosium

b. indium

c. gadolinium.

d. gold

17.

The quality of the results from a neutron radiographic facility is best determined by:

a. reference standards

b. image-quality indicators.

c. neutron flux measurement

d. densitometer readings

18.

Flaws in the imaging screens can be separated from actual flaws in a part being radiographed by:

a. performing a photographic copy of the original neutron radiograph using X-ray duplicating film

b. comparing a neutron radiograph of the parts to a blank neutron radiograph of the same imaging screen with no parts in place.

c. increasing the exposure time of the radiograph

d. decreasing the temperature of the developer solution

19.

The best method for determining how resolution affects the ability to interpret the radiograph of parts is by:

a. radiographing parts that have known measured defects.

b. using a penetrometer

c. using a penetrometer containing cadmium wedges

d. using a penetrometer containing plastic wedges

20.

The slope of a straight line joining two points of specified density on the characteristic curve of a film is known as the:

a. speed of the curve

b. latitude

c. average gradient.

d. density

21.

The range of densities which are satisfactory for interpretation is a measure of the:

a. subject contrast of a radiograph

b. sensitivity of a radiograph

c. latitude of a radiograph.

d. definition of a radiograph

22.

The transmission of neutrons by a material varies:

a. directly with the square of the distance from the source

b. directly with the thickness of the material

c. inversely with the amount of scattering in the material

d. exponentially with the thickness of the material.

23.

Which of the following is not a factor in determining subject contrast?

a. the nature of the specimen

b. the neutron energy

c. the type of film used.

d. the intensity and distribution of the scattered radiation

24.

When viewing a radiograph, an image of the back of the cassette superimposed on the image of the specimen is noted. This is most likely due to:

a. undercut

b. overexposure

c. neutron intensity is too high

d. back scatter.

25.

A qualitative term often used to indicate the size of the smallest detail which can be seen in a radiograph is:

a. radiographic sensitivity.

b. radiographic definition

c. radiographic contrast

d. subject contrast

26.

The quantitative measure of film blackening is referred to as:

a. definition

b. photographic density.

c. film contrast

d. radiographic contrast

27.

A curve that relates density to the logarithm of exposure or relative exposure is called:

a. a sensitivity curve

b. a density-exposure curve

c. a characteristic curve.

d. an X-ray intensity curve

28.

Subject contrast is affected by:

a. thickness differences in the specimen

b. neutron energy

c. scattered radiation

d. all of the above.

29.

Contrast enhancement of a neutron radiograph can be achieved by:

a. using photographic techniques with X-ray duplicating film.

b. increasing the radiography system resolution

c. varying the object-to-film distance

d. increasing the gamma radiation reaching the film from the source

30.

The uniformity of a neutron radiograph is best determined by measuring the density of a:

a. neutron radiograph at several locations with many parts in place

b. neutron radiograph at several locations with no parts in place copy of a neutron radiograph with.

c. photographic many parts in place

d. photographic copy of a neutron radiograph with no parts in place

31.

The density measurement in a neutron radiograph that is of most interest in determining part flaws is the density measurement:

a. at the center of the film

b. at the corner of the film

c. at the edge of the film

d. in the area of interest within the parts being radiographed.

32.

A neutron radiograph beam from a reactor was measured to have a thermal neutron flux of 3.4 x 10⁶n • cm^-2 • S^-1 and a gamma rate of 26 R/h. Which of the following would be the neutron-to-gamma ratio in units of n• cm^-2•mR^-1?

a. 4.7 x 10²

b. 4.7 x 10^5.

c. 2.1 x 10⁵

d. 2.1 x 10²

33.

In direct neutron radiography using gadolinium, cleanliness is essential when handling film cassettes because:

a. dust or lint between the film and the gadolinium shows as a flaw in the radiograph.

b. dust on the outside of the film cassette is always visible in the neutron radiograph

c. dust is highly absorbent to neutrons

d. dust greatly affects the development of X-ray film

34.

A dysprosium conversion screen is exposed to a thermal neutron beam. After a decay time of 6.9 hours:

a. 3/4 of the original activation will remain

b. 1/2 of the original activation will remain

c. 1/8 of the original activation will remain.

d. there will be no change from the original activation levels

35.

When sharp, black, bird-foot-shaped marks appear on discontinuities, they are probably caused by: the film in areas where there are no possible

a. prolonged development in an old developer

b. exposure of the film to natural cosmic radiation

c. static charges caused by friction.

d. inadequate rinsing after fixing

36.

Images of discontinuities close to the source side of the specimen become less clearly defined as the:

a. source-to-object distance increases

b. thickness of the specimen increases.

c. size of the neutron source decreases

d. thickness of the specimen decreases

37.

The amount of unsharpness of a radiograph is:

a. directly proportional to the object-to-film distance and inversely proportional to the size of the source

b. directly proportional to the size of the source and inversely proportional to the source-to-object distance.

c. inversely proportional to the object-to-film distance and directly proportional to the source-to-object distance

d. inversely proportional to the size of the source and the object-to-film distance

38.

The most commonly used converter material is:

a. copper

b. tungsten

c. gold

d. gadolinium.

39.

As the effective energy of the radiation from the conversion screen increases:

a. film graininess increases

b. film graininess decreases

c. radiographic definition decreases.

d. film speed decreases

40.

A general rule governing the application of the geometric principles of shadow formation state that the:

a. neutrons should proceed from as large a source area as other considerations will allow

b. distance between the source and material should be as small as practical

c. film should be as far as possible from the object being radiographed

d. axis of the beam should be as nearly perpendicular to the film as possible, to preserve spatial relationships.

41.

A neutron radiograph made with an exposure of 12 minutes has a density of 0.8 in the region of maximum interest. It is desired to increase the density in this area to 2.0. By reference to a characteristic curve of the film, it is found that the difference in Log E between a density of 0.8 and 2.0 is 0.76. The antilogarithm of 0.76 is 5.8. What must be the new exposure time to produce a radiograph of density 2.0?

a. 30 minutes

b. 21.12 minutes

c. 69.6 minutes.

d. 16 minutes

42.

Which of the following factors will not materially influence the image density of a neutron radiograph?

a. the type of film used

b. the size of the film.

c. the type of conversion screen used

d. the exposure time

43.

X-ray films with large grain size:

a. will produce radiographs with better definition than a film with a small grain size

b. have slower speeds than those with a relatively small grain size

c. have higher speeds than those with a relatively small grain size.

d. will take longer to expose properly than a film with a relatively small grain size

44.

The uneven distribution of developed grains within the emulsion of a processed X-ray film causes the subjective impression of:

a. graininess.

b. streaks

c. spots

d. white scum

45.

An X-ray-type film used for neutron radiography having wide latitude also has, by definition:

a. poor definition

b. low contrast.

c. high speed

d. none of the above

46.

The gradient of a characteristic curve for a photographic film for neutron radiography is the greatest as a density of:

a. <0.5

b. 0.5

c. 1.0

d. >1.0.

47.

For practical purposes, the shape of the characteristic curve of an X-ray film is:

a. independent of the type of film used

b. independent of the energy of the neutron beam.

c. drastically changed when neutron energy is changed

d. primarily determined by the subject contrast

48.

The interval between the time a film is placed in a fixer solution and the time when the original diffuse, yellow milkiness disappears is known as the:

a. clearing time.

b. fixing time

c. hardening time

d. oxidation time

49.

Improper geometric factors, poor contact between film and conversion screen, and the graininess of the film are possible causes of:

a. high film density

b. poor definition.

c. fogged film

d. increased contrast

50.

The activity of the fixer diminishes after being used for a period of time because:

a. the active ingredients evaporate

b. the active ingredients are absorbed by the radiograph

c. the fixer solution accumulates soluble silver salts.

d. the active ingredients settle to the bottom of the tank

51.

It is known that the density of a film increases with increasing exposure up to a maximum value. Increasing the exposure beyond this point results in an actual decrease in density. These phenomena is referred to as:

a. density-intensity turnabout

b. subject contrast inversion

c. film contrast inversion

d. reversal.

52.

The developer solution should be discarded when the quantity of replenisher added equals:

a. the original quantity of developer

b. 2 to 3 times the original quantity of developers.

c. 5 to 6 times the original quantity of developer

d. 10 times the original quantity of developer

53.

Agitation of the X-ray film during the development process by means of mechanical stirrers or circulating pumps may:

a. speed the developing cycle

b. help replenish the developer

c. cause undesirable preferential flow of developers along certain paths.

d. cause reticulation

54.

In processing radiographs, the hourly flow of water in the wash tank should be:

a. 2 to 3 times the volume of the tank

b. 4 to 8 times the volume of the tank.

c. at least 151 L (40 gal) per hour

d. varied continuously in proportion to the number of radiographs being developed

55.

The slope (steepness) of a characteristic curve is a measure of the:

a. subject contrast

b. radiographic definition

c. radiographic contrast

d. film contrast.

56.

As the development time increases:

a. the characteristic curve grows steeper and moves to the left.

b. the characteristic curve grows steeper and moves to the right

c. the characteristic curve remains the same in shape but moves to the left

d. there is little effect on the characteristic curve

57.

Which of the following instruments would most likely by used to detect small leaks in a radiation barrier?

a. a film badge

b. a fountain pen type of ionization chamber

c. a Geiger counter.

d. a dosimeter

58.

The quantity of neutron radiation upon an area of film for an exposure:

a. is the product of the neutron flux and time.

b. is the neutron flux

c. varies exponentially with time

d. varies inversely proportional to the time

59.

The energy of the neutron is expressed by which of the following units of measurement?

a. curie

b. roentgen

c. half-life

d. electron volts.

60.

Neutrons for fast-neutron radiography are obtainable from:

a. accelerators

b. radioactive sources

c. reactors

d. all of the above.

61.

“Macroscopic cross-section” as applied to neutrons is analogous to γ rays:

a. cross section

b. mean free path

c. attenuation coefficient.

d. wavelength

62.

For high-quality radiographs, a 25-micrometer thick gadolinium screen combined with fine-grain X-ray film requires an exposure of about:

a. 3 x 103 n/cm2

b. 3 x 105 n/cm2

c. 3 x 107 n/cm2

d. any of the above.

63.

Neutron monitoring outside a radiography exposure area may be done with:

a. a Geiger counter

b. a “cutie-pie” (ionization chamber)

c. a BF₃, proportional counter.

d. all of the above

64.

Special neutron-sensitive film dosimeters:

a. should be worn by neutron radiographers

b. employ a film-screen combination principle similar to radiography

c. also give a measure of γ dose

d. all of the above.

65.

For the same beam intensity, which of the following will give the largest biological dose?

a. fast neutrons.

b. thermal neutrons

c. γαμμα rays

d. all are equal by definition

66.

For fast-neutron monitoring, a thermal-neutron-sensitive radiation counter may be used in conjunction with:

a. a moderator.

b. an ionization chamber

c. a conversion foil

d. a collimator

67.

If the biological dose rate at 1.5 m (5 ft) from a point source of radiation is 10 mrem/h, then the minimum permissible distance at which a worker may remain for continuous (full work week) exposure is about: (Assume maximum exposure of 100 mrem/week)

a. 3 m (10 ft).

b. 6 m (20 ft)

c. 15.2 m (50 ft)

d. 30.5 m (100 ft)

68.

In a radiation area where the dose rate is established to be 25 mrem/h, a worker during a work week may spend no more than (assume minimum exposure of 100 mrem/week)

a. 6 minutes

b. 1 hour

c. 4 hours.

d. 8 hours

69.

Upon exiting from a radiation zone, you begin a G-M survey of an object. The needle begins to rise and then suddenly drops to zero. You should assume that the:

a. G-M tube has ruptured

b. G-M jammed because of too much radiation.

c. G-M probe has become grossly contaminated

d. rubbers are not contaminated

70.

The G-M cannot be used to establish dose rates because:

a. the G-M is not reliable and tends to drift

b. the beta shield is too thick on the G-M

c. the G-M does not account for the degree of ionization or energy absorption of ionizing particles or photons.

d. the G-M is designed to detect only alpha contamination on scintillators

71.

A direct reading pocket dosimeter may be sensitive to what radiation?

a. β

b. γ

c. γ, n

d. either a or b.

72.

A film dosimeter useful for neutron radiographers will be sensitive to what radiation?

a. α, β, γ, η

b. α, β, γ

c. β, γ

d. β, γ, η.

73.

Thermal-neutron-sensitive radiation counters usually contain:

a. gadolinium

b. cadmium

c. boron.

d. lead

74.

If 2 mm (0.08 in.) of plastic attenuates a thermal neutron beam by a factor of 2, then 2 mm (0.8 in.) will attenuate it by approximately a factor of:

a. 10

b. 100

c. 1 000.

d. 10 000

75.

The high attenuation of thermal neutrons by plastics is due primarily to:

a. scattering.

b. absorption

c. both a and b

d. none of the above

76.

Photographic density is a quantitative measure of:

a. film thickness

b. film weight

c. film blackening.

d. object opacity

77.

The film exposed to a density of 2 will transmit what percentage of the light incident upon it?

a. 50%

b. 25%

c. 2%

d. 1%.

78.

An image-quality indicator is:

a. a scanning densitometer

b. a chemical stain

c. a penetrameter.

d. all of the above

79.

Radiography using the transfer method implies that the imaging screen:

a. is placed behind the film

b. is placed in front of the film

c. is very thin

d. becomes radioactive.

80.

In the list below, the best filter material for making an epithermal neutron beam is:

a. cadmium.

b. water

c. boron

d. lead

81.

Fast neutron attenuation:

a. increases significantly with increasing atomic mass

b. decreases significantly with increasing atomic

c. has significant random variations with atomic mass mass

d. is similar for most materials.

82.

Which of the following is most widely used in the detector for imaging fast neutrons?

a. hydrogenous.

b. gold

c. aluminum material

d. lithium

83.

The linear attenuation coefficient for neutrons is described in the following equation: μ = No, which of the following statements is true?

a. N= number of nuclei per cm3 of attenuating material

b. σ₁ = total cross-section (cm2) equal to the sum of absorption and scattering cross-sections

(σ_α +σ_s) absorption cross-section

c. σ_α = absorption cross-section

d. all the above.

84.

Real-time imaging of thermal neutron radiography can be performed with which of the following detectors?

a. gadolinium

b. dysprosium

c. zinc sulfide + lithium fluoride.

d. europium

85.

A neutron beam undergoes which of the following interactions when penetrating matter?

a. scatter.

b. pair production

c. Thompson effect

d. Compton scattering

86.

A Geiger-Muller instrument is a:

a. pocket-sized dosimeter

b. scintillation counter

c. hand-held survey meter counter.

d. proportional

87.

The thermalization factor is the:

a. ratio between the total 4л fast neutron yield and the peak thermal neutron flux.

b. dose of ionizing radiation that can be absorbed per unit volume

c. mean square distance while slowing down

d. mean time spent diffusing in a test object before being captured in a detector

88.

Energy classification places epithermal neutrons in the range:

a. below 0.01 eV

b. from 0.3 eV to 100 keV

c. from 0.3 to 10 000 eV.

d. from 10 keV to 20 MeV

89.

A shutter for turning the neutron beam ON and OFF at a nuclear reactor can be accomplished by:

a. the electronic circuitry

b. a small mechanical camera shutter

c. Boral shutters.

d. aluminum shutters

90.

Gadolinium screens have been shown to resolve high- contrast images separated by distances as small as:

a. 2.5 mm (0.1 in.)

b. 1 mm (0.04 in.)

c. 0.1 mm (0.004 in.)

d. 0.01 mm (0.0004 in.).

91.

The best radiographic resolution and contrast capability for direct exposure radiography has been obtained with:

a. gadolinium screens.

b. indium

c. silver

d. cadmium

92.

Radiography requiring utmost speed and no more than 0.05 mm (0.002 in.) resolution would require which of the following detectors?

a. gadolinium screens

b. scintillator screens.

c. dysprosium screens

d. silver screens

93.

In which of the following neutron beams does the intensity follow the inverse square law?

a. divergent beam.

b. soller slit beam

c. neutron spectrometer beam

d. monochromatizing crystal beam

94.

Neutron radiography:

a. complements X-radiography

b. can discriminate between neighboring elements such as boron and carbon

c. can inspect large thicknesses of heavy metals

d. all of the above.

95.

Neutron radiography extends radiographic capability for detecting cracks in small:a

a. aluminum pins

b. iron pins

c. magnesium pins

d. plutonium pins.

96.

Film fogging during radiography of radioactive materials (5 000 R/h at 31 cm [1 ft]) is minimized by using:

a. direct X-radiographic methods

b. pinhole autoradiography

c. transfer method with dysprosium screens.

d. photography

97.

What radiography technique should be used for obtaining improved penetration of 20% Pu, U-235 enriched fuel pellets, ~6 mm diameter?

a. thermal neutron with gadolinium screen

b. epithermal neutron and indium screen.

c. epithermal neutron and dysprosium

d. autoradiography

98.

Neutron radiography can be used for inspecting which of the following applications?

a. presence of explosives in a metal device

b. presence of foreign material such as oil

c. lubricants in metal systems

d. all of the above.

99.

Disadvantages of the transfer technique include the it:

a. is time-consuming

b. requires many imaging foils

c. provides lesser resolution than the gadolinium direct method

d. all of the above.

Question 1 of 99

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A nuclear reactor produces neutrons that have energies distributed from less than 0.01 eV to greater than 20 MeV. For most neutron radiography, the thermal energy group is used. This group has energies:

The primary radiation mechanism for darkening X-ray film when the direct radiography process is used employing gadolinium screens is:

Neutron radiography is an excellent tool for determining:

Which of the following materials is the greatest attenuator of thermal neutrons?

Thermal neutrons that are relatively free from higher energy components are obtained by allowing neutrons from the source (reactor, radioactive source, accelerator) to pass through moderating material. This material may be:

The sample part may become radioactive as the result of neutron activation during the neutron exposure. As a general rule, the level of radioactivity will be:

The absorption of neutrons in an object depends upon:

The energy of the neutrons in a neutron beam:

directly influences the choice of usable conversion screens.

Which of the following conversion screens has the longest half-life?

The unique and important properties of the neutron in neutron radiography come primarily from the fact that it is a nuclear particle that is electrically neutral. The lack of electric charge means that its electrostatic interaction with the atom’s electrons is:

The rare earth is frequently used in neutron radiography. An interesting feature of this family of elements is:

A thin sheet of gadolinium foil, in intimate contact with photographic film during neutron exposure, will increase film density because:

For direct neutron radiography, precaution has to be taken to reduce the gamma-ray background of most sources as this tends to obscure the neutron radiograph. This may be done by:

The transfer exposure technique, sometimes called the indirect technique, uses neutron converters that have a reasonably long radioactive half-life. Which of the following would be a good candidate?

Which of the following neutron radiography converter foils cannot be used for transfer or indirect radiography?

The quality of the results from a neutron radiographic facility is best determined by:

Flaws in the imaging screens can be separated from actual flaws in a part being radiographed by:

The best method for determining how resolution affects the ability to interpret the radiograph of parts is by:

The slope of a straight line joining two points of specified density on the characteristic curve of a film is known as the:

The range of densities which are satisfactory for interpretation is a measure of the:

The transmission of neutrons by a material varies:

Which of the following is not a factor in determining subject contrast?

When viewing a radiograph, an image of the back of the cassette superimposed on the image of the specimen is noted. This is most likely due to:

A qualitative term often used to indicate the size of the smallest detail which can be seen in a radiograph is:

The quantitative measure of film blackening is referred to as:

A curve that relates density to the logarithm of exposure or relative exposure is called:

Subject contrast is affected by:

Contrast enhancement of a neutron radiograph can be achieved by:

The uniformity of a neutron radiograph is best determined by measuring the density of a:

The density measurement in a neutron radiograph that is of most interest in determining part flaws is the density measurement:

A neutron radiograph beam from a reactor was measured to have a thermal neutron flux of 3.4 x 106n • cm-2 • S-1 and a gamma rate of 26 R/h. Which of the following would be the neutron-to-gamma ratio in units of n• cm-2•mR-1?

In direct neutron radiography using gadolinium, cleanliness is essential when handling film cassettes because:

A dysprosium conversion screen is exposed to a thermal neutron beam. After a decay time of 6.9 hours:

When sharp, black, bird-foot-shaped marks appear on discontinuities, they are probably caused by: the film in areas where there are no possible

Images of discontinuities close to the source side of the specimen become less clearly defined as the:

The amount of unsharpness of a radiograph is:

The most commonly used converter material is:

As the effective energy of the radiation from the conversion screen increases:

A general rule governing the application of the geometric principles of shadow formation state that the:

Which of the following factors will not materially influence the image density of a neutron radiograph?

X-ray films with large grain size:

The uneven distribution of developed grains within the emulsion of a processed X-ray film causes the subjective impression of:

An X-ray-type film used for neutron radiography having wide latitude also has, by definition:

The gradient of a characteristic curve for a photographic film for neutron radiography is the greatest as a density of:

For practical purposes, the shape of the characteristic curve of an X-ray film is:

The interval between the time a film is placed in a fixer solution and the time when the original diffuse, yellow milkiness disappears is known as the:

Improper geometric factors, poor contact between film and conversion screen, and the graininess of the film are possible causes of:

The activity of the fixer diminishes after being used for a period of time because:

It is known that the density of a film increases with increasing exposure up to a maximum value. Increasing the exposure beyond this point results in an actual decrease in density. These phenomena is referred to as:

The developer solution should be discarded when the quantity of replenisher added equals:

Agitation of the X-ray film during the development process by means of mechanical stirrers or circulating pumps may:

In processing radiographs, the hourly flow of water in the wash tank should be:

The slope (steepness) of a characteristic curve is a measure of the:

As the development time increases:

Which of the following instruments would most likely by used to detect small leaks in a radiation barrier?

The quantity of neutron radiation upon an area of film for an exposure:

The energy of the neutron is expressed by which of the following units of measurement?

Neutrons for fast-neutron radiography are obtainable from:

“Macroscopic cross-section” as applied to neutrons is analogous to γ rays:

For high-quality radiographs, a 25-micrometer thick gadolinium screen combined with fine-grain X-ray film requires an exposure of about:

Neutron monitoring outside a radiography exposure area may be done with:

Special neutron-sensitive film dosimeters:

For the same beam intensity, which of the following will give the largest biological dose?

For fast-neutron monitoring, a thermal-neutron-sensitive radiation counter may be used in conjunction with:

If the biological dose rate at 1.5 m (5 ft) from a point source of radiation is 10 mrem/h, then the minimum permissible distance at which a worker may remain for continuous (full work week) exposure is about: (Assume maximum exposure of 100 mrem/week)

In a radiation area where the dose rate is established to be 25 mrem/h, a worker during a work week may spend no more than (assume minimum exposure of 100 mrem/week)

Upon exiting from a radiation zone, you begin a G-M survey of an object. The needle begins to rise and then suddenly drops to zero. You should assume that the:

The G-M cannot be used to establish dose rates because:

A direct reading pocket dosimeter may be sensitive to what radiation?

A film dosimeter useful for neutron radiographers will be sensitive to what radiation?

Thermal-neutron-sensitive radiation counters usually contain:

If 2 mm (0.08 in.) of plastic attenuates a thermal neutron beam by a factor of 2, then 2 mm (0.8 in.) will attenuate it by approximately a factor of:

The high attenuation of thermal neutrons by plastics is due primarily to:

Photographic density is a quantitative measure of:

The film exposed to a density of 2 will transmit what percentage of the light incident upon it?

An image-quality indicator is:

Radiography using the transfer method implies that the imaging screen:

In the list below, the best filter material for making an epithermal neutron beam is:

Fast neutron attenuation:

A neutron radiograph beam from a reactor was measured to have a thermal neutron flux of 3.4 x 10⁶n • cm^-2 • S^-1 and a gamma rate of 26 R/h. Which of the following would be the neutron-to-gamma ratio in units of n• cm^-2•mR^-1?