1. A Novel Low-Background Photomultiplier Tube Developed for Xenon Based Detectors
- Author
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Yun, Youhui, Zhou, Zhizhen, An, Baoguo, Gao, Zhixing, Han, Ke, Liu, Jianglai, Liang, Yuanzi, Liu, Yang, Meng, Yue, Qian, Zhicheng, Shang, Xiaofeng, Si, Lin, Song, Ziyan, Wang, Hao, Wang, Mingxin, Wang, Shaobo, Wu, Liangyu, Wu, Weihao, Wu, Yuan, Yan, Binbin, Yan, Xiyu, Yuan, Zhe, Zhang, Tao, Zhao, Qiang, and Zeng, Xinning
- Subjects
Physics - Instrumentation and Detectors ,High Energy Physics - Experiment - Abstract
Photomultiplier tubes (PMTs) are essential in xenon detectors like PandaX, LZ, and XENON experiments for dark matter searches and neutrino properties measurement. To minimize PMT-induced backgrounds, stringent requirements on PMT radioactivity are crucial. A novel 2-inch low-background R12699 PMT has been developed through a collaboration between the PandaX team and Hamamatsu Photonics K.K. corporation. Radioactivity measurements conducted with a high-purity germanium detector show levels of approximately 0.08 mBq/PMT for $\rm^{60}Co$ and 0.06~mBq/PMT for the $\rm^{238}U$ late chain, achieving a 15-fold reduction compared to R11410 PMT used in PandaX-4T. The radon emanation rate is below 3.2 $\rm \mu$Bq/PMT (@90\% confidence level), while the surface $\rm^{210}Po$ activity is less than 18.4 $\mu$Bq/cm$^2$. The electrical performance of these PMTs at cryogenic temperature was evaluated. With an optimized voltage distribution, the gain was enhanced by 30\%, achieving an average gain of $4.23 \times 10^6$ at -1000~V and -100~$^{\circ}$C. The dark count rate averaged 2.5~Hz per channel. Compactness, low radioactivity, and robust electrical performance in the cryogenic temperature make the R12699 PMT ideal for next-generation liquid xenon detectors and other rare event searches.
- Published
- 2024