DEAP-3600暗物质探测器中的电磁本底与钾-42活度
核实验
2019-11-06 v1 天体物理仪器与方法
摘要
DEAP-3600实验利用位于SNOLAB地下2.1 km处的3.3吨单相液态氩（LAr）靶搜寻WIMP暗物质。暗物质相互作用的实验信号为keV量级的Ar核反冲（NR），产生由PMT观测的128 nm LAr闪烁光子。DEAP-3600中最大的本底是由探测器材料内部与外部放射性起源的与射线诱导的电子反冲（ER）。本文发展并描述了DEAP-3600中ER相互作用的本底模型。该模型基于若干分量，分别来自LAr中的放射性同位素、离位材料分析测量以及专门的独立原位分析。此先验信息被用于ER分量对247.2 d数据集的贝叶斯拟合，以模拟周围探测器材料中的放射性。虽然利用LAr闪烁光快慢分量间的巨大差异，通过脉冲形状甄别可实现ER与NR的优异甄别，但对ER本底及探测器部件活度的详尽认知，为探测器中其他关键本底类型——中子与α粒子——设定了有价值的约束。此外，DEAP-3600中LAr内Ar的活度通过测量K的子体衰变确定。这一宇宙射线活化的痕量同位素对于使用大气氩的其他稀有事件搜寻（如DarkSide-20k、GERDA或LEGEND）在更高能量处是相关本底。大气中Ar的比活度被发现为 Bq/kg氩。
引用
@article{arxiv.1905.05811,
title = {Electromagnetic Backgrounds and Potassium-42 Activity in the DEAP-3600 Dark Matter Detector},
author = {R. Ajaj and G. R. Araujo and M. Batygov and B. Beltran and C. E. Bina and M. G. Boulay and B. Broerman and J. F. Bueno and P. M. Burghardt and A. Butcher and M. Cárdenas-Montes and S. Cavuoti and M. Chen and Y. Chen and B. T. Cleveland and K. Dering and F. A. Duncan and M. Dunford and A. Erlandson and N. Fatemighomi and G. Fiorillo and A. Flower and R. J. Ford and D. Gallacher and P. García Abia and S. Garg and P. Giampa and D. Goeldi and V. V. Golovko and P. Gorel and K. Graham and D. R. Grant and A. L. Hallin and M. Hamstra and P. J. Harvey and C. Hearns and A. Joy and C. J. Jillings and O. Kamaev and G. Kaur and A. Kemp and I. Kochanek and M. Kuźniak and S. Langrock and F. La Zia and B. Lehnert and X. Li and O. Litvinov and J. Lock and G. Longo and P. Majewski and A. B. McDonald and T. McElroy and T. McGinn and J. B. McLaughlin and R. Mehdiyev and C. Mielnichuk and J. Monroe and P. Nadeau and C. Nantais and C. Ng and A. J. Noble and C. Ouellet and P. Pasuthip and S. J. M. Peeters and V. Pesudo and M. -C. Piro and T. R. Pollmann and E. T. Rand and C. Rethmeier and F. Retière and E. Sanchez García and R. Santorelli and N. Seeburn and P. Skensved and B. Smith and N. J. T. Smith and T. Sonley and R. Stainforth and C. Stone and V. Strickland and B. Sur and E. Vázquez-Jáuregui and L. Veloce and S. Viel and J. Walding and M. Waqar and M. Ward and S. Westerdale and J. Willis and A. Zuñiga-Reyes},
journal= {arXiv preprint arXiv:1905.05811},
year = {2019}
}