论文标题
识别低背景应用的辐射钨
Identification of radiopure tungsten for low background applications
论文作者
论文摘要
在本文中，我们探讨了辐射钨的可用性及其作为低密度屏蔽材料的潜力，可用于低背景应用。对于紧凑型盾牌设计，通常使用铅。金属钨和钨伪合金达到高达19.3 gcm $^{ - 3} $的较高密度，并且没有表现出明显的$^{210} $ PB活动，这是一种典型的铅污染物。在几个$γ$ -Ray筛选广告系列中，我们能够识别出与活动相似或好于1 mbqkg $^{ - 1} $中的钨样品，in $^{232} $ th，$^{40} $ k，$^{60} $ co和$^{238} $ u dean $ u dean the of。与制造商合作，我们进一步将$^{238} $ u衰减链的第一部分中的持续污染降低了$ \ sim $ 2.5的一倍，至（305 $ \ pm $ 30）mbqkg $^{ - 1} $。借助蒙特卡洛模拟，基于钨的原型设置和专用测量值的构建，与铅相比，钨的屏蔽能力得到了广泛的研究。具体而言，研究了宇宙辐射对浅深度背景的影响。我们表明，可以通过抑制抑制外部$γ$放射的相当数量的钨来替换铅，从而可以实现6-40％的降低（取决于确切的屏蔽构型）。总体而言，使用钨的许多好处，尤其是针对低于100 keV的低能应用。这项工作中介绍的伪四合一合金为多种应用铺平了道路，尤其是在粒子和Astroparpicle物理搜索程序中的背景抑制方面。
In this article we explore the availability of radiopure tungsten and its potential as high density shield material for low background applications. For compact shield designs, conventionally, lead is used. Metallic tungsten and tungsten pseudo-alloys reach higher densities up to 19.3 gcm$^{-3}$ and do not exhibit a significant $^{210}$Pb activity, which is a typical intrinsic contamination in lead. Within several $γ$-ray screening campaigns we were able to identify tungsten samples with activities similar or better than 1 mBqkg$^{-1}$ in $^{232}$Th, $^{40}$K, $^{60}$Co and the second part of the $^{238}$U decay chain. In cooperation with a manufacturer we further reduced a persisting contamination in the first part of the $^{238}$U decay chain by a factor of $\sim$2.5 down to (305$\pm$30) mBqkg$^{-1}$. With Monte Carlo simulations, the construction of prototype tungsten-based setups and dedicated measurements, the shield capability of tungsten in comparison to lead was extensively studied. Specifically, the impact of cosmogenic radiation on the background at shallow depth was investigated. We showed that a 6-40% reduction (depending on the exact shield configuration) in the muon-induced neutron fluence is achievable by replacing lead with an equivalent amount of tungsten regarding the suppression of external $γ$-radiation. Overall, many benefits using tungsten especially for low energy applications below a few 100 keV are found. The pseudo-tungsten alloy presented in this work paves the way for several applications especially regarding background suppression in particle and astroparticle physics search programs.
