Neutron Radiography is a non-destructive imaging technique utilizing thermal neutrons. Classically, it has been used for quality control purposes in industries which require precision machining such as aircraft engines. Today, the most important application of neutron radiography is in testing the performance of fuel cells by imaging water flow in the cells in situ. Neutron radiography has also been used in the art world and in archeology to authenticate paintings and examine artifacts made of metal or stone. Neutrons have many advantages for imaging over visible light, x-rays or electrons. The advantages include greater penetration depth into most materials, considerable variations in contrast between chemical elements and isotopes, and weaker radiation damage than other penetrating radiation.
MIT Reactor has two facilities suitable for neutron imaging projects for both scientific and industrial applications. One facility provides a thermal neutron beam with L/D ratio of up to 1000 when the beam is of 2” diameter. Another facility provides a vertical beam of 10” diameter, with smaller L/D.
An image of ASTM standard samples, plastic screw (thread period of 1 mm) and Gd plate with 1 mm pin-hole aperture. The ASTM standard in the center left is made of Teflon with 2 boron-nitride disks, 2 cadmium wires and two led disks (invisible). The standard sample on the center right is made of plastic of various thickness separated by aluminum blades of different width. Spatial resolution is better than 500 micron in this low L/D setup. Contamination with gamma-radiation is very low.
In addition to research possibilities in advanced materials, the neutron imaging facility is an excellent teaching tool for MIT students and faculty in imaging.
NRL Neutron Radiography contact: