ASTREA: Accelerator mass spectrometry Survey of Trace Radionuclides for Experiments in Astroparticle physics

在过去的三十年里，实验粒子物理学的巨大进步使得在寻找无中微子双β衰变（0？暗物质（DM）的直接探测。桌面仪器已成为数吨重的地下探测器，对极其罕见的相互作用具有出色的灵敏度。这一进展的关键是，在探测器建造之前和建造期间，主要通过材料筛选，将探测器中残留的天然放射性本底降低许多数量级。建造这样的巨人的每一种材料和组件都必须经过彻底的分析，如果可能的话，还要进行优化，因为最轻微的天然放射性污染都可能通过压倒预期的信号来破坏实验的灵敏度。许多技术进步以及地下安装有助于过去和现在实验的成功。但我们已经达到了通常无法通过典型方法满足的材料筛选要求。加速器质谱（AMS）是其他领域的一项成熟技术，为实现最终灵敏度提供了希望的灯塔。AMS使用粒子加速器来提高灵敏度，并提供独特而突出的优势：-直接扫描导电材料;这与唯一的其它直接方法，使用Ge检测器的γ光谱学，-总分子背景抑制，比常规的高灵敏度质谱技术如ICP-MS更有优势。使用气体电离检测器和高分辨率交变磁和电扇区的单离子灵敏度，实现无噪声检测和一系列信号背景优化策略。 - 应用于筛选中/短寿命同位素，例如用于现场电子和高压系统的各种塑料和其他绝缘体中的210 Pb，在这一请求中，我们考虑AMS材料筛选贡献针对三个具体项目，这些项目具有重要的加拿大贡献和领导作用：nEXO、NEWS-G和DEAP/DarkSide正在考虑在世界上最深、最干净的地下实验室之一SNOLab运行。我们建议调查由于U和Th链的痕量放射性，测量210 Pb和226 Ra的浓度，在铜，钛，丙烯酸和聚合物薄膜。 助理E.位于渥太华大学的拉隆德加速器质谱计（AEL-AMS）设施是加拿大唯一的加速器质谱计实验室，运行着一个3 MV、多元素的加速器质谱计系统，专门设计用于灵敏、有效地测量像锕系元素这样大质量的元素。AEL-AMS已经建立了样品制备化学实验室，配备了处理各种分析物原子和样品基质的设备，并负责开发新的应用程序和所需的协议和技术基础设施，以促进此类分析。

In the last three decades, tremendous advances in experimental particle physics have enabled strong progression in the search for neutrinoless double beta decay (0?ßß) and the direct detection of dark matter (DM). Tabletop instruments have become multi-tonne underground detectors with excellent sensitivity to extremely rare interactions. Critical to this progress has been the reduction of residual natural radioactive backgrounds in the detectors by many orders of magnitude, accomplished mainly through material screening, before and during detector construction. Every material and component for building such giants has to be thoroughly analyzed and, if possible, optimized, as the slightest natural radioactive contamination can ruin the experiment's sensitivity by overwhelming the expected signal. Many technical advances, as well as underground installation have contributed to the success of past and current experiments. But we have reached material screening requirements that often cannot be met by typical methods. Accelerator Mass Spectrometry (AMS), an established technique in other fields, provides a beacon of hope to achieve the ultimate sensitivity. AMS uses a particle accelerator to enhance sensitivity and offer unique and outstanding advantages: - direct scanning of electrically conducting materials; this compares favourably with the only other direct method, gamma spectroscopy using a Ge detector, - total molecular background suppression, an advantage over regular high sensitivity mass spectrometry techniques like ICP-MS. - single ion sensitivity using gas ionization detectors and high resolution alternating magnetic and electric sectors, that enable noise-free detection and a series of signal to background optimization strategies. - application to screening for medium/short lifetime isotopes, e.g. 210Pb in a wide array of plastics and other insulators used for in-situ electronics and high voltage systems, In this request, we consider AMS material screening contributions targeted to three specific projects that have significant Canadian contributions and leadership: nEXO, NEWS-G and DEAP/DarkSide, and which are considering operating at SNOLab , one of the deepest and cleanest underground laboratories in the world. We propose to investigate the trace radioactivity due to U and Th chains, measure the concentration of 210Pb and 226Ra, in copper, titanium, acrylic and thin polymer films. The A. E. Lalonde AMS (AEL-AMS) facility at the University of Ottawa, the only AMS laboratory in Canada, operates a 3 MV, multi-element AMS system, specifically designed to sensitively and efficiently measure elements as massive as the actinides. AEL-AMS has implemented sample preparation chemistry labs equipped to handle a wide array of analyte atoms and sample matrices and has a mandate to develop new applications and the required protocols and technical infrastructure to facilitate such analyses.