Study of inactive layer uniformity and charge collection efficiency of a p-type point-contact germanium detector

J L Ma; Q Yue; Q Wang; J Li; H T Wong; S T Lin; S K Liu; L Wang; H Jiang; L T Yang; L P Jia; J H Chen; W Zhao

doi:10.1016/j.apradiso.2017.05.023

Study of inactive layer uniformity and charge collection efficiency of a p-type point-contact germanium detector

Appl Radiat Isot. 2017 Sep:127:130-136. doi: 10.1016/j.apradiso.2017.05.023. Epub 2017 May 30.

Authors

J L Ma¹, Q Yue², Q Wang³, J Li⁴, H T Wong⁵, S T Lin⁶, S K Liu⁴, L Wang⁴, H Jiang⁴, L T Yang¹, L P Jia⁴, J H Chen⁵, W Zhao⁴

Affiliations

¹ Department of Physics, Tsinghua University, Beijing 100084, China; Key Laboratory of Particle and Radiation Imaging (Ministry of Education) and Department of Engineering Physics, Tsinghua University, Beijing 100084, China.
² Key Laboratory of Particle and Radiation Imaging (Ministry of Education) and Department of Engineering Physics, Tsinghua University, Beijing 100084, China. Electronic address: yueq@mail.tsinghua.edu.cn.
³ Department of Physics, Tsinghua University, Beijing 100084, China; Center for High Energy Physics, Tsinghua University, Beijing 100084, China; Collaborative Innovation Center of Quantum Matter, Beijing 100084, China.
⁴ Key Laboratory of Particle and Radiation Imaging (Ministry of Education) and Department of Engineering Physics, Tsinghua University, Beijing 100084, China.
⁵ Institute of Physics, Academia Sinica, Taipei 11529, Taiwan.
⁶ College of Physical Science and Technology, Sichuan University, Chengdu 610064, China.

PMID: 28586704
DOI: 10.1016/j.apradiso.2017.05.023

Abstract

The characteristics of the surface inactive layer of a 1-kg-mass p-type point-contact germanium detector were studied. The thickness of the inactive layer and its uniformity on the top and lateral surfaces were measured. A charge collection efficiency function was developed according to the Monte Carlo simulation to describe the charge collection capacity along the depth within this inactive layer. In the energy range below 18keV, the surface, bulk, and total spectra of ⁵⁷Co, ¹³³Ba, ¹³⁷Cs, and ⁶⁰Co from simulations based on the charge collection efficiency function were well consistent with those from experiments.

Keywords: CDEX; Charge collection efficiency; Inactive layer; PPCGe.