ASNT Neutron Radiography 3

Question 1

Which industrial application is MOST commonly inspected using neutron radiography that would be difficult to inspect with conventional X-radiography?

Accepted Answer

Corrosion and moisture trapped inside aircraft aluminum structures

Answer

Cracks in steel weld beads

Answer

Porosity in titanium castings

Answer

Delamination in carbon fiber laminates

Question 2

What is the purpose of the cadmium ratio measurement in a neutron beam characterization?

Accepted Answer

To determine the ratio of thermal to epithermal neutrons in the beam

Answer

To measure the ratio of gadolinium to cadmium in the converter screen

Answer

To quantify beam divergence at the specimen plane

Answer

To calculate the ratio of neutron flux to gamma flux

Question 3

In digital neutron radiography, which detector type directly converts neutron interactions to electronic signals with high spatial resolution?

Accepted Answer

Neutron-sensitive CCD camera coupled to a scintillating screen

Answer

Computed radiography (CR) phosphor imaging plates with neutron converter

Answer

Indirect flat-panel detector with gadolinium scintillator

Answer

Thermoluminescent dosimeter array

Question 4

What is the primary function of a beam purity indicator (BPI) in neutron radiography?

Accepted Answer

To indicate the relative amount of gamma contamination in the neutron beam

Answer

To measure the total neutron flux at the specimen plane

Answer

To verify that the L/D ratio meets specification

Answer

To calibrate the film processing chemicals

Question 5

According to ASNT personnel qualification guidelines, which certification level is authorized to interpret neutron radiographic results and write procedures?

Accepted Answer

Level III

Answer

Level I

Answer

Level II

Answer

Trainee (Level 0)

Question 6

Which of the following statements correctly describes the geometric unsharpness (Ug) in neutron radiography?

Accepted Answer

Ug increases as the object-to-detector distance increases or as the L/D ratio decreases

Answer

Ug increases as the L/D ratio increases

Answer

Ug decreases as the object-to-detector distance increases

Answer

Ug is independent of source aperture size

Question 7

What is the principal reason neutron radiography is performed in shielded vaults or beamline facilities rather than in open field conditions?

Accepted Answer

The intense neutron flux needed for practical exposure times requires a nuclear reactor or large accelerator with substantial biological shielding

Answer

Neutrons require a vacuum environment to maintain coherence

Answer

Neutrons are rapidly absorbed by air, making field use impractical

Answer

Film sensitivity is reduced by ambient temperature fluctuations