A ³He beam stop for minimizing gamma-ray and fast-neutron background

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• 作者：Danyal Turkoglu ; R. Gregory Downing…
• 关键词：Prompt gamma ; ray activation analysis ; Instrument design ; Monte Carlo radiation transport ; Neutron shielding ; Gamma ; ray background
• 刊名：Journal of Radioanalytical and Nuclear Chemistry
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：311
• 期：2
• 页码：1243-1249
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Nuclear Chemistry; Physical Chemistry; Nuclear Physics, Heavy Ions, Hadrons; Diagnostic Radiology; Inorganic Chemistry;
• 出版者：Springer Netherlands
• ISSN：1588-2780
• 卷排序：311

文摘

Prompt gamma-ray activation analysis facilities with high neutron currents (≥109 s−1) generate triton-induced fast neutrons from 6Li-loaded collimators and beam stops at rates that damage gamma-ray detectors. We develop an alternative beam stop design using 3He gas that produces negligible gamma-ray and fast-neutron background following neutron absorption. Replacing a 6Li glass beam stop with a test cell containing 2.5 MPa cm of 3He reduced fast neutron production by 73 %. An optimal 3He beam stop design with a 100-µm-thick entrance window, modeled using MCNP6, enables operation of detectors closer to the beam stop.