Radon in the DRIFT-II directional dark matter TPC: emanation, detection and mitigation
Radon in the DRIFT-II directional dark matter TPC: emanation, detection and mitigation
复制标题
DRIFT-II 定向暗物质 TPC 中的氡：发射、检测和缓解
DOI：
10.1088/1748-0221/9/11/p11004
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发表时间：
2014
影响因子：
1.3
通讯作者：
Boulby Mine
中科院分区：
文献类型：
--
作者：
J. Battat;J. Brack;E. Daw;A. Dorofeev;A. Ezeribe;J. Fox;J. Gauvreau;M. Gold;L. J. Harmon;J. Harton;J. Landers;E. R. Lee;D. Loomba;J. Matthews;E. Miller;A. Monte;A. S. Murphy;S. Paling;N. Phan;M. Pipe;M. Robinson;S. Sadler;A. Scarff;D. Snowden;N. Spooner;S. Telfer;D. Walker;D. Warner;L. Y. P. Department;Wellesley College;USA.;D. Physics;Colorado State University;Astronomy;U. Sheffield;Uk;Occidental College;U. N. Mexico;S. O. Physics;U. Edinburgh;Stfc Boulby Underground Science Facility;Boulby Mine
从材料中散发出的氡气在环境科学中很有意义，也是稀有事件非加速器粒子物理实验中的主要关注点，如暗物质和双β衰变搜索，它是背景的主要来源。在暗物质实验中值得注意的是氡子体反冲（RPR）的产生，氡子体同位素的低能（100 keV）反冲，可以模拟WIMP相互作用的预期信号。这里介绍的是测量氡射气从探测器材料在1立方米的DRIFT-II定向暗物质气体时间投影室实验的结果。建造和操作的氡射气设施，这项工作的描述，沿着分析，以持续监测DRIFT数据的存在下，内部222 Rn和218 Po。应用这种分析历史漂移数据，我们展示了如何系统的替代品的探测器材料，该设备选择的低氡射气，导致了一个因素的1000万美元的减少内部氡率。水平被认为是一致的总和从单独的氡射气测量的内部材料，也与直接测量使用一个附加的阿尔法光谱仪。目前的DRIFT探测器DRIFT-IId对222 Rn的灵敏度为2.5 μBql−1，具有当前的分析效率，可能开辟DRIFT技术作为材料灵敏氡分析的新工具。
Radon gas emanating from materials is of interest in environmental science and also a major concern in rare event non-accelerator particle physics experiments such as dark matter and double beta decay searches, where it is a major source of background. Notable for dark matter experiments is the production of radon progeny recoils (RPRs), the low energy (∼ 100 keV) recoils of radon daughter isotopes, which can mimic the signal expected from WIMP interactions. Presented here are results of measurements of radon emanation from detector materials in the 1 m3 DRIFT-II directional dark matter gas time projection chamber experiment. Construction and operation of a radon emanation facility for this work is described, along with an analysis to continuously monitor DRIFT data for the presence of internal 222Rn and 218Po. Applying this analysis to historical DRIFT data, we show how systematic substitution of detector materials for alternatives, selected by this device for low radon emanation, has resulted in a factor of ∼ 10 reduction in internal radon rates. Levels are found to be consistent with the sum from separate radon emanation measurements of the internal materials and also with direct measurement using an attached alpha spectrometer. The current DRIFT detector, DRIFT-IId, is found to have sensitivity to 222Rn of 2.5 μBql−1 with current analysis efficiency, potentially opening up DRIFT technology as a new tool for sensitive radon assay of materials.