Detector Optimization for the SuperCDMS Experiment

几个观测天文学实验的结果表明，宇宙中大约85%的物质不是由普通粒子组成的。破译这种暗物质的性质对于宇宙学、天体物理学、高能粒子物理学以及我们对引力的理解都具有根本的重要性。一个主要的假设是，暗物质是由弱相互作用大质量粒子（WIMPs）组成的，这是一种超越粒子物理学标准模型的基本粒子，但在包括超对称性在内的各种扩展中得到了预测。由NSF和DOE联合支持的低温暗物质搜索（CDMS）合作，率先使用基于超导薄膜传感器的低温声子介导探测器，以区分这种WIMP在核上的罕见散射与其他背景事件。利用我们在苏丹矿场的强大技术，CDMS是目前（2005年7月）世界上最灵敏的WIMP搜索实验，是原来的10倍。该NSF奖项提供的两年资金将有助于支持圣克拉拉大学（SCU）继续积极参与苏丹CDMS实验的运营。这笔资金还将部分支持该小组继续研究用于低温探测器应用的超导传感器技术。这项工作包括超导铝合金传感器的物理和技术研究（可能对SuperCDMS和其他实验感兴趣），以及与CDMS合作者继续合作，将当前基于钨的技术可行地扩展到SuperCDMS的更大基板。SCU小组将继续负责使用斯坦福大学现有的快速周转稀释制冷设备，为CDMS合作提供超导薄膜的快速表征。在这两年的资助期内，将对基于物理范围和提高器件制造产量的承诺的未来传感器技术进行评估。通常是两个本科生该集团受益于其强大的联系，在附近的机构，特别是斯坦福大学和加州大学伯克利分校的团体。这些机构的CDMS合作者慷慨地为SCU组提供了广泛的低温和设备制造设施，他们的支持使SCU组能够进行各种与CDMS及其他相关的物理实验，否则SCU组的成本过高。

Results from several observational astronomy experiments show that about 85% of the matter in the universe is not made of ordinary particles. Deciphering the nature of this dark matter would be of fundamental importance to cosmology, astrophysics, high-energy particle physics, and our understanding of gravity. A leading hypothesis is that dark matter is comprised of Weakly Interacting Massive Particles, or WIMPs, an elementary particle beyond the Standard Model of particle physics, but predicted in various extensions including Supersymmetry. The Cryogenic Dark Matter Search (CDMS) Collaboration, supported jointly by NSF and DOE, has pioneered the use of low temperature phonon-mediated detectors based on superconducting thin-film sensors to distinguish the rare scattering of such WIMPs on nuclei from other background events. Using our powerful technology in the Soudan mine, CDMS is currently (July 05) the most sensitive WIMP search experiment in the world, by a factor of ten. The two years of funding provided by this NSF award will help support the Santa Clara University (SCU) group continue its active participation in the operation of the CDMS experiment at Soudan. The funding will also partially support the group's continued work on superconducting sensor technologies for cryogenic detector applications. This work includes physics and technology-focused investigations of superconducting aluminum alloy sensors (potentially of interest for SuperCDMS and other experiments), as well as continued work with CDMS collaborators on feasible extensions of the current tungsten-based technology to larger substrates for SuperCDMS. The SCU group will continue to be responsible for using existing, fast turn-around, dilution-refrigerator facilities at Stanford University to provide the CDMS collaboration with rapid characterization of superconducting films. Evaluations of future sensor technologies based on both physics reach and promise for enhanced device fabrication yields will be ongoing throughout this two year funding period.The SCU group includes the P.I. and typically two undergraduates. The group benefits tremendously from its strong ties to groups at nearby institutions, particularly Stanford and UC Berkeley. CDMS collaborators at these institutions generously provide the SCU group access to their extensive cryogenic and device fabrication facilities and their support has allowed the SCU group to perform a variety of physics experiments related to CDMS and beyond, that otherwise would have been cost-prohibitive for the SCU group alone.