Neutron Radiographic Testing (NR) Review Questions Flashcards
1
Q
1. The highest intensity sources of thermal neutrons are? A. Cf-252 isotopes B. Accelerators C. Nuclear fission reactors D. Cosmic radiation
A
C. Nuclear fission reactors
2
Q
2. Neutrons for fast-neutron radiography are not obtainable from: A. Accelerators B. Radioactive sources C. Reactors D. X-Ray machines
A
D. X-Ray machines
3
Q
3. A radioactive source used for neutron radiography is: A. Pu-239 B. Co-60 C. Cs-137 D. Cf-252
A
D. Cf-252
4
Q
4. The energy of the neutron is expressed in which of the following units of measurement? A. Curies (becquerels) B. Roentgens (coulombs per kilogram) C. Rems (sieverts) D. Electron volts
A
D. Electron volts
5
Q
- A normally desirable feature of a thermal neutron beam fo neutron radiography is:
A. Background gamma radiation intensity
B. Relatively low fast-neutron intensity
C. Low angular divergence
D. Relatively high thermal neutron intensity
A
B. Relatively low fast-neutron intensity
6
Q
6. Material that slows down neutrons is called? A. A moderator B. A accumulator C. A limitor D. A collimator
A
A. A moderator
7
Q
7. The primary radiation mechanism for darkening X-ray film when the direct neutron radiography process is used with gadolinium screens is? A. Alpha particles B. Electrons C. Gamma rays D. Light emission
A
B. Electrons
8
Q
8. Neutron radiography using the transfer method requires that the imaging screen must: A. Be placed behind the film B. Be placed in front of the film C. Be very thin D. Become radioactive
A
D. Become radioactive
9
Q
9. Which of the following neutron radiography converter foils cannot be used for transfer or indirect radiography? A. Dysprosium B. Indium C. Gadolinium D. Gold
A
C. Gadolinium
10
Q
- The most suitable films for producing neutron radiographs are:
A. Red sensitive films
B. Instant-type films
C. Industrial X-Ray films
D. Emulsions that contain no silver halides
A
C. Industrial X-Ray films
11
Q
- Materials that are exposed to thermal neutron beams:
A. Must not be handled for at least 3 min after exposure has ceased
B. Must be stored in a lead-lined room
C. May be radioactive after exposure to neutrons has ceased
D. Should be monitored by means of neutron counter
A
C. May be radioactive after exposure to neutrons has ceased
12
Q
12. Lead is: A. A good neutron shield B. Corroded by neutron exposures C. A relatively poor neutron absorber D. An efficient conversion screen
A
C. A relatively poor neutron absorber
13
Q
13. If 2 mm (0.08”) of plastic attenuated a thermal neutron beam by a factor of 2, then 20 mm (.8”) will attenuate it by approximately a factor of: A. 10 B. 20 C. 200 D. 1,000
A
D. 1,000
14
Q
- Materials in common usage for moderation of fast-neutron sources include:
A. Aluminum, magnesium and tin
B. Water, plastic, paraffin and graphite
C. Neon, argon and xenon
D. Tungsten, cesium, antimony and columbium
A
B. Water, plastic, paraffin and graphite
15
Q
- The main reason for using neutron radiography in place of X-Radiography is:
A. A lower cost
B. Higher resolution
C. The ability to image objects and materials not possible with X-Rays
D. It is a simpler radiographic procedure when required than X-Radiography
A
C. The ability to image objects and materials not possible with X-Rays