Identification of the anomalous fast bulk events in a p-type point contact germanium detector

• Published in: arXiv.org
• Main Authors: Li, Renmingjie, Liu, Shukui, Lin, Shinted, Yang, Litao, Qian Yue, Fang, Changhao, Jia, Haitao, Jiang, Xi, Li, Qianyun, Liu, Yu, Yan, Yulu, Zhao, Kangkang, Zhang, Lei, Tang, Changjian, Xing, Haoyang, Zhu, Jingjun
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 21.09.2022
• Subjects: Beta decay; Coherent scattering; Dark matter; Elastic scattering; Energy resolution; Germanium; Neutrinos; Physics - High Energy Physics - Experiment; Physics - Instrumentation and Detectors; Point contact; Pulse shape; Sensors; Spatial resolution
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2201.02961

The ultralow detection threshold, ultralow intrinsic background, and excellent energy resolution of p-type point-contact germanium detector are important for rare-event searches, in particular for the detection of direct dark matter interactions, coherent elastic neutrino-nucleus scattering, and neutrinoless double beta decay. Anomalous bulk events with an extremely fast rise time are observed in the CDEX-1B detector. We report a method of extracting fast bulk events from bulk events using a pulse shape simulation and reconstructed source experiment signature. Calibration data and the distribution of X-rays generated by intrinsic radioactivity verified that the fast bulk experienced a single hit near the passivation layer. The performance of this germanium detector indicates that it is capable of single-hit bulk spatial resolution and thus provides a background removal technique.