Cold neutron prompt gamma-ray activation analysis at NIST - Recent developments

The cold neutron capture prompt gamma-ray activation analysis (CNPGAA) spectrometer located in the Cold Neutron Research Facility (CNRF) at NIST has proven useful for the analysis of hydrogen and other elements in a wide variety of materials. Modifications of the instrument and the CNRF have resulted in improved measurement capabilities for PGAA. The addition of an atmosphere-controlled sample chamber and Compton suppression have reduced gamma-ray background and increased signal-to-noise ratio. More recent revisions are expected to yield still further improvement in analytical capabilities. Replacement of the D2O ice cold source with a liquid H-2 moderator is expected to yield a 5-10 fold increase in neutron capture rate, and improved neutron and gamma-ray shielding will result in further reduction of the background Other modifications to the instrument allow easier sample mounting and mon: precise positioning of samples in the neutron beam. Significant improvements in detection limits and analytical accuracy are expected.