How Much Do You Know About N-Ray?

How Much Do You Know About N-Ray? Take our quiz to find out.


Neutron imaging is a nondestructive testing method you might have heard of before, but probably haven’t had a chance to use. Despite being a powerful method for inspecting components in many industries, only a small community of NDT professionals are truly aware of neutron radiography, or N-ray.

Are you a part of this small community? Take our quiz to find out:

(Answers at the bottom of the quiz)

1. Neutron imaging is more useful than X-ray imaging for…

a. Detecting internal flaws in cast parts
b. Identifying bonding flaws in adhesives
c. Detecting and identifying the positions of o-rings, seals, lubricants, and adhesives inside complex assemblies
d. All of the above

2. Neutrons, unlike X-rays, are better for penetrating…

a. Dense materials
b. Light materials
c. Water
d. Plastics

3. Neutron radiation interacts most strongly with…

a. The electron cloud
b. The atomic nucleus
c. Photons
d. Other neutrons

4. True or false: Neutron imaging can only be done with a nuclear reactor.

a. True
b. False

5. True or false: Neutron imaging can be used in field work.

a. True
b. False

6. Neutron radiation is produced by:

a. Fission of uranium
b. Fusion of deuterium with tritium
c. Fusion of deuterium with deuterium
d. All of the above

7. True or false: In neutron imaging, the collimator focuses the neutron beam using electromagnets.

a. True
b. False

8. Neutron imaging has not often been used as a nondestructive testing tool because…

a. Neutrons are actually very destructive
b. Neutron imaging has only a few specific uses
c. Current imaging facilities are difficult to access
d. The objects being imaged remain “hot” for too long

9. Objects exposed to neutron radiation remain “hot” for how long?

a. About twelve hours
b. Roughly 66 hours
c. One week
d. 700 thousand years

10. What is the ASTM standard for neutron imaging?

a. ASTM E1931
b. ASTM E545 and E748
c. ASTM E1742 and E1742M
d. ASTM E1032

All done? Let's see which questions you got right and learn more about the ones you got wrong:

Answer Key:

  1. d. All of the above
    In all of these situations and more, neutron imaging is ideal for picking up details that X-ray imaging would likely miss.
  2. a. Dense materials
    Because of the way neutrons interact with matter, they penetrate dense materials (including most metals and lead) more easily than they would pass through lighter materials (such as water and plastics).
  3. b. The atomic nucleus
    Neutrons interact with the atomic nucleus, which is why their rate of attenuation does not increase with density the way it does with X-rays. This is why neutrons pass through dense metals so easily while stopping when they reach lighter substances such as water and plastics.
  4. b. False
    Phoenix’s fusion neutron generators produce enough neutron radiation to create sharp, clear images without the burdens and supply risk associated with reactors. Our upcoming facility, PNIC, will be the first industrial radiography facility to provide neutron imaging services without the use of a reactor.
  5. b. False
    Currently, neutron imaging isn’t used for fieldwork due to the sheer scale of the technology needed to create an image in a timely fashion. However, Phoenix is continuing to work on creating more and more compact high-yield neutron sources, which will hopefully make neutron imaging more viable for fieldwork.
  6. d. All of the above
    All of these nuclear reactions and more produce neutron radiation. In all of these reactions, extra neutrons are left behind and become neutron radiation.
  7. b. False
    Because neutron radiation is comprised of neutral particles with neither a positive nor a negative charge, magnetic fields have no effect on them.
  8. c. Current imaging facilities are difficult to access
    Although neutron imaging as an industrial tool has existed since the 1950s, its near-exclusive reliance on nuclear reactors has made the technique difficult to access, especially since the number of reactors available has been declining.
  9. a. About twelve hours
    When an object is irradiated for neutron imaging or for radiation effects testing, how long it takes to “cool down” depends on what it’s made out of and how long it has been exposed to radiation. In most cases, though, the radiation drops to a safe level below 0.04 millirems within twelve hours.
  10. b. ASTM E545 and E748
    ASTM E545 describes the standard test method for determining image quality in direct thermal neutron radiographic examination and ASTM E748 is the standard guide for thermal neutron radiography of materials.

Thanks for taking our quiz. We hope you had as much fun taking this quiz as we did putting it together!