A multi-parameter discrimination digital positron annihilation lifetime spectrometer using a fast digital oscilloscope-猫眼课题宝

一种基于快速数字示波器的多参数鉴别数字正电子湮灭寿命谱仪

DOI：

10.1016/j.nima.2021.165974

发表时间：

2021-11

期刊：

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

影响因子：

通讯作者：

中科院分区：

其他

文献类型：

作者：

Q. H. Zhao;R. Ye;H. B. Wang;L. H. Cong;J. D. Liu;H. J. Zhang;B. J. Ye

正电子湮没寿命谱（PAL）技术在材料微结构表征中有着广泛的应用。它对材料缺陷有很高的敏感性。本文介绍了我们如何研制一台数字PAL光谱仪，它有两个氟化钡（BaF 2）探测器，用快速数字示波器阅读数据。采用多参数鉴别方法和多种脉冲平滑算法，使数字PAL光谱仪获得了较好的时间性能。采用两个BaF2探测器，在符合模式下，对0.511MeV湮没γ射线的时间分辨率达到160ps。所实现的多参数判别方法比传统的能量判别方法能更有效地剔除错误同相轴。随着事件鉴别的增强，数字PAL谱仪的时间性能得到了改善，这导致更准确的PAL表征。在寿命测量中，PAL光谱仪的时间分辨率约为130 ps，这比大多数PAL光谱仪要好得多。采用多参数判别方法，可以有效地降低误检同相轴的分辨率分量，改善PAL谱的前沿畸变。

Positron annihilation lifetime (PAL) spectroscopy is widely used in the characterization of material microstructures. It has a very high sensitivity to the material defects. This paper describes how we developed a digital PAL spectrometer with two barium fluoride (Ba F 2) detectors and reading the data with a fast digital oscilloscope. We achieved better time performance for the digital PAL spectrometer using a multi-parameter discrimination method and various pulse smoothing algorithms. With two Ba F 2 detectors in the coincidence mode, we achieved a time resolution of 160 ps for 0.511 MeV annihilation gamma rays. The multi-parameter discrimination method implemented can remove incorrect events more effectively than the conventional energy discrimination method. With this enhancement in event discrimination, the digital PAL spectrometer’s time performance has improved, which results in more accurate PAL characterization. In a lifetime measurement, the PAL spectrometer’s time resolution is about 130 ps, which is much better than most PAL spectrometers. With the multi-parameter discrimination method, the resolution component from the incorrect events decreases drastically, and the leading edge distortion of the PAL spectrum is significantly improved.