Neutron Depth Profiling "Chambers"

This picture presents a previous version of the NDP System at the NIST Center for Neutron Research (NCNR). A small neutron beam (~1 cm diameter) from the reactor passes through the blue shielding at the left and into the stainless steel vacuum chamber in the center. The neutron beam at the sample position is described in some detail here. Non-reacted neutrons then continue out of the chamber and are absorbed in the beam stop by lithium polymers and borated-aluminum surrounded by additional radiation shielding. To view the inside of the chamber look here. At the bottom left are two mechanical vacuum pumps. One is for first roughing the vacuum down in the chamber after mounting a sample; the other pump assists the turbomolecular pump (located under the chamber) that maintains a high vacuum during analyses.