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

ASTREA：用于天体粒子物理学实验的痕量放射性核素的加速器质谱调查

• 批准号: SAPPJ-2021-00033
• 负责人: Kieser, William
• 金额: $ 7.5万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Project
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=762631
• 关键词: ASTREA; Accelerator; mass; spectrometry; Survey

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.

在过去的三十年中，实验粒子物理学的巨大进步使得寻找无中微子双 β 衰变 (0?ßß) 的工作取得了长足的进展，并且直接探测暗物质 (DM) 的仪器已成为数吨级的地下探测器。对极其罕见的相互作用具有出色的灵敏度，这一进展的关键是探测器中残留的天然放射性本底减少了许多数量级，这主要是通过在探测器建造之前和建造过程中的材料筛选来实现的。彻底进行分析，并在可能的情况下进行优化，因为最轻微的自然放射性污染可能会压倒预期信号，从而破坏实验的灵敏度。许多技术进步以及地下安装为过去和当前实验的成功做出了贡献。加速器质谱 (AMS) 是其他领域的一项成熟技术，它为实现最终灵敏度提供了希望。AMS 使用粒子加速器来增强灵敏度，并提供独特而突出的优势。 :-直接扫描导电材料；这与唯一的其他直接方法（使用 Ge 探测器的伽马光谱法）相比具有优势， - 总分子背景抑制，优于常规高灵敏度质谱技术（如 ICP-MS） - 使用气体的单离子灵敏度。电离探测器和高分辨率交替磁电扇区，可实现无噪声检测和一系列信号背景优化策略 - 用于筛选中/短寿命同位素，例如 210Pb。用于现场电子和高压系统的各种塑料和其他绝缘体，在此请求中，我们考虑 AMS 材料筛选的贡献，目标是针对加拿大具有重大贡献和领导地位的三个特定项目：nEXO、NEWS-G 和 DEAP/DarkSide ，并正在考虑在 SNOLab 进行操作，SNOLab 是世界上最深、最干净的地下实验室之一，我们建议调查 U 和 Th 链的痕量放射性，测量 210Pb 和 210Pb 的浓度。 226Ra，采用铜、钛、丙烯酸和聚合物薄膜制成。渥太华大学的 A. E. Lalonde AMS (AEL-AMS) 设施是加拿大唯一的 AMS 实验室，运行着 3 MV 多元素 AMS 系统，专门设计用于AEL-AMS 拥有能够处理各种分析物原子和样品基质的样品制备化学实验室，能够灵敏、高效地测量锕系元素等质量元素。任务是开发新的应用程序以及所需的协议和技术基础设施以促进此类分析。