A linear fast neutron beam chopper has been deployed at a prompt gamma activation analysis instrument, enabling in-beam activation analysis of short-lived (T1/2 > ~ 10 ms) neutron capture products without the need for sample transfer. This article describes the design and operation of the chopper system and measurement results from test samples containing Se-77 (T1/2 = 17.36 s) and Yb-175m (T1/2 = 0.0682 s). The chopper timing was optimized for a specific isotope in each measurement, demonstrating an advantage of the programmable system. The linear response of the total gated counts in the decay phase to the incremented Se and Yb masses demonstrates the suitability of the system for quantitative analysis. Theoretical calculations based on the experimental parameters were in good agreement with the observed results. An example that illustrates the separation of overlapping energy peaks by the use of time-stamped list mode data acquisition is shown in a sample containing Yb-175m and Dy-165 (T1/2 = 75.4 s).

中文翻译：

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短切冷中子束活化分析


线性快中子束斩波器已部署在瞬发伽马活化分析仪器上，无需样品转移即可对短寿命（T1/2 > ~ 10 ms）中子捕获产物进行束内活化分析。本文介绍了斩波系统的设计和操作以及含有 Se-77 (T1/2 = 17.36 s) 和 Yb-175m (T1/2 = 0.0682 s) 的测试样品的测量结果。在每次测量中针对特定同位素优化了斩波器定时，展示了可编程系统的优势。衰变阶段的总门控计数对增加的 Se 和 Yb 质量的线性响应证明了系统用于定量分析的适用性。基于实验参数的理论计算与观测结果非常吻合。包含 Yb-175m 和 Dy-165 (T1/2 = 75.4 s) 的样品中显示了一个示例，说明通过使用带时间戳的列表模式数据采集来分离重叠能量峰。