USE OF NEUTRON BEAMS FOR CHEMICAL-ANALYSIS AT NIST

At the National Institute of Standards and Technology, there are two t echniques for chemical analysis that use neutron beams from the reacto r for target irradiation: neutron depth profiling (NDP) and prompt gam ma-ray activation analysis (PGAA). There are two facilities for each t echnique, one equipped with a thermal neutron beam and the other, with a cold neutron beam. In addition, focused beams of cold neutrons will be used to measure the two-dimensional element distributions by PGAA and three-dimensional distributions by NDP. This paper includes a brie f description of the facilities, the measurement capabilities of each, some recent applications of NDP and PGAA, and neutron focusing as app lied to these techniques.