Delayed charge recovery discrimination of passivated surface alpha events in P-type point-contact detectors
Delayed charge recovery discrimination of passivated surface alpha events in P-type point-contact detectors
复制标题
P型点接触探测器中钝化表面α事件的延迟电荷恢复辨别
DOI：
10.1088/1742-6596/888/1/012079
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
I. Zhitnikov
中科院分区：
文献类型：
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作者：
J. Gruszko;N. Abgrall;I. Arnquist;F. Avignone;A. Barabash;F. Bertrand;A. Bradley;V. Brudanin;M. Busch;M. Buuck;T. Caldwell;Y. Chan;C. Christofferson;P. Chu;C. Cuesta;J. Detwiler;C. Dunagan;Y. Efremenko;H. Ejiri;S. Elliott;A. Fullmer;A. Galindo;T. Gilliss;G. Giovanetti;M. Green;I. Guinn;V. Guiseppe;R. Henning;E. Hoppe;M. Howe;B. Jasinski;K. Keeter;M. Kidd;S. Konovalov;R. Kouzes;J. Leon;A. M. Lopez;J. MacMullin;R. Martin;R. Massarczyk;S. Meijer;S. Mertens;J. Orrell;C. O'Shaughnessy;A. Poon;D. Radford;J. Rager;K. Rielage;R. Robertson;E. Romero;B. Shanks;M. Shirchenko;A. Suriano;D. Tedeschi;J. Trimble;R. Varner;S. Vasilyev;K. Vetter;K. Vorren;B. White;J. Wilkerson;C. Wiseman;W. Xu;E. Yakushev;C. ;V. Yumatov;I. Zhitnikov
马约拉纳演示器使用高纯度锗探测器阵列搜索76Ge的中微子双β衰变。如果观测到，这一过程将证明轻子数在自然界中不是一个守恒量，这意味着大统一，并解释了宇宙中物质对反物质的优势。在这种大颗粒探测器阵列中，阿尔法粒子构成了一个有问题的背景。在马约拉纳演示器中，已经观察到的事件与钝化表面上产生的能量退化α相一致，导致在感兴趣的区域中存在中微子双β衰变的潜在背景贡献。然而，也观察到，当能量沉积发生在非常接近钝化表面时，电荷通过体漂到该表面上，然后沿其漂移，迁移率大大降低。这导致减少提示信号和可测量的变化，在一个记录的脉冲尾部的斜率。在这篇文章中，我们讨论了这些事件的特征，并开发了一种滤波器，可以识别这种延迟电荷恢复的发生，从而在分析中有效地抑制钝化表面α事件。
The Majorana Demonstrator searches for neutrinoless double-beta decay of 76Ge using arrays of high-purity germanium detectors. If observed, this process would demonstrate that lepton number is not a conserved quantity in nature, with implications for grand-unification and for explaining the predominance of matter over antimatter in the universe. A problematic background in such large granular detector arrays is posed by alpha particles. In the Majorana Demonstrator, events have been observed that are consistent with energy-degraded alphas originating on the passivated surface, leading to a potential background contribution in the region-of-interest for neutrinoless double-beta decay. However, it is also observed that when energy deposition occurs very close to the passivated surface, charges drift through the bulk onto that surface, and then drift along it with greatly reduced mobility. This leads to both a reduced prompt signal and a measurable change in slope of the tail of a recorded pulse. In this contribution we discuss the characteristics of these events and the development of a filter that can identify the occurrence of this delayed charge recovery, allowing for the efficient rejection of passivated surface alpha events in analysis.