Lindstrom Richard M
National Institute of Standards and Technology, Gaithersburg, MD 20899.
J Res Natl Inst Stand Technol. 1993 Jan-Feb;98(1):127-133. doi: 10.6028/jres.098.009.
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.
作为冷中子研究设施（CNRF）的一部分，一台用于瞬发伽马活化分析的永久性、全职仪器即将完工。该分析系统的设计已针对高伽马探测效率和低本底进行了优化，特别是对于氢的探测。由于中子束的纯度高，屏蔽要求较低，散射俘获本底也很低。由于样品 - 探测器几何结构紧凑，其灵敏度（每克分析物的计数率）比该反应堆现有的马里兰 - 国家标准与技术研究院热中子仪器高四倍。目前已经实现了几微克的氢本底，这有望在许多需要对材料中的少量氢进行定量无损分析的应用中发挥作用。
