Neutron Depth Profiling "Chambers"

Neutron Depth Profiling (NDP) is a nondestructive analytical technique for measuring the concentration profile of isotopes from several light elements as a function of depth. The concentration profile in the first few micrometers of a surface is determined by analyzing the energy spectrum of charged particles promptly emitted following neutron capture by the element.


 A view from overhead the NDP System located at the NIST Center for Neutron Research (NCNR). A small diameter (~1 cm) neutron beam passes through the blue shielding at the upper left and passes through the stainless steel chamber in the center. The neutron beam at the sample position is described in some detail here. Non-reacted neutrons continue through the chamber to be captured in the beam stop of borated-aluminum encased in radiation shielding. To view the inside of the chamber take a look here.

At the bottom left are two vacuum pumps. One to rough down the vacuum in the chamber after a sample change; the other serves to assist the turbomolecular pump (located under the chamber) that maintains a high vacuum during analyses.