Prompt-gamma activation analysis

Abstract

A permanent, full-time instrument for prompt-gamma activation analysis is nearing completion as part of the Cold Neutron Research Facility (CNRF). The design of the analytical system has been optimized for high gamma detection efficiency and low background, particularly for hydrogen. Because of the purity of the neutron beam, shielding requirements are modest and the scatter-capture background is low. As a result of a compact sample-detector geometry, the sensitivity (counting rate per gram of analyte) is a factor of four better than the existing Maryland-NIST thermal-neutron instrument at this reactor. Hydrogen backgrounds of a few micrograms have already been achieved, which promises to be of value in numerous applications where quantitative nondestructive analysis of small quantities of hydrogen in materials is necessary.

Neutron vibrational spectroscopy and first-principles calculations of the ternary hydridesLi4Si2H(D)andWu1, Zhou2, Udovic3 et al. 2007Phys. Rev. B171110View full textAdd to dashboardCite

“…The compositions and structures of the products after each synthesis process were characterized using laboratory x-ray diffraction ͑Rigaku, D-MAX/UltimaIII͒ and neutron prompt-gamma activation analysis ͑PGAA͒ techniques. 10 Powders were wrapped in a Mo envelope and sealed in a stainless-steel tube during the high-temperature hydrogenation. All sample handling was performed in a He-filled glovebox to avoid oxidation reactions.…”

Gas Evolution and Capacity Fading in LiFexMn1-xPO4/Graphite Cells Studied by Neutron Imaging and Neutron Induced Prompt Gamma Activation Analysis

“…31 PGAA is based on the radiative neutron capture process: after the neutron capture, the atomic nuclei release the excitation energy in the form of characteristic gamma rays whose energies identify the elements, while the elemental composition can be determined from their intensities. 32 The samples in our experiments were irradiated in a cold neutron beam with a flux of ≈ 1.35 · 10 10 cm -2 s -1 for about two hours. The prompt gamma rays were detected with a high-purity germanium (HPGe) detector with a relative efficiency of 60% surrounded by a bismuth germanate scintillator annulus as a Compton suppressor.…”

Structural Study of an Unusual Cubic Pyrochlore Bi1.5Zn0.92Nb1.5O6.92

“…The composition of this specimen was analyzed using cold neutron prompt g-ray activation analysis (PGAA) at the NIST Cold Neutron Research Facility (13). The technique involves sample irradiation by a beam of neutrons, resulting in neutron capture by different chemical elements.…”