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arXiv · 2511.16704

Ultra-Low background germanium spectrometers at the China Jinping Underground Laboratory

Jikai Chen·Zhi Zeng·Hao Ma·Jianping Cheng
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Abstract

Four ultra-low background germanium spectrometers, called GeTHU, have been installed at the first phase of China Jinping Underground Laboratory (CJPL-I), and served for material screening of dark matter and neutrino experiments. Recently, a new multi-detector spectrometer with five germanium detectors has been developed and installed at the second phase of CJPL (CJPL-II) with a minimum detectable activity (MDA) of about 10 {\mu}Bq/kg. In addition, another fifteen GeTHU-like spectrometers have been installed at CJPL-II with an MDA of about 1 mBq/kg. This paper will introduce the ultra-low background germanium spectrometers including shielding design, background characteristics and application to material screening.

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Jikai Chen, Zhi Zeng, Hao Ma, Jianping Cheng. 2025-11-19. Ultra-Low background germanium spectrometers at the China Jinping Underground Laboratory. https://arxiv.org/abs/2511.16704

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