Radon and its progenies are significant sources of background in rare event detection experiments, including dark matter searches like the PandaX-4T experiment and other rare decay studies such as neutrinoless double beta decay (NLDBD). In order to measure and control radon emanation for these experiments, we have developed two specialized radon measurement systems: a radon emanation measurement system suitable for small-sized samples with a blank rate of 0.03±0.01 mBq in the 12.3 L counting chamber, and a radon trap system designed for large-volume samples using low-temperature radon trapping techniques, which improves the sensitivity by a factor of 30 with 1 standard liter per minute (slpm) gas flow and 6 hours trapping time. To boost the detection sensitivity, various surface treatments of the chambers were investigated, including mechanical polishing, electrochemical polishing, and mirror polishing, which reveals that smoother surfaces lead to lower radon emanation rates. In addition, treatments such as applying epoxy coating and covering with aluminized Mylar to stainless steel chambers can also reduce the radon emanation by (90±7)% and (60±12)%, respectively.
@article{arxiv.2503.00739,
title = {Development of High-Sensitivity Radon Emanation Measurement Systems with Surface Treatment Optimization},
author = {Yuan Wu and Lin Si and Zhicheng Qian and Youhui Yun and Yue Meng and Jianglai Liu and Zhixing Gao and Hao Wang and Liangyu Wu and Yuanzi Liang},
journal= {arXiv preprint arXiv:2503.00739},
year = {2025}
}