A Path to Superconducting Nanowire Readout of Xe- based detectors

超导纳米线单光子探测器（SNSPD）具有接近1的量子效率（QE）、低至10-4 Hz/器件的超低暗计数率和精确的亚10 ps定时分辨率，具有真空紫外（VUV）灵敏度，作为PPAN社区使用的广泛闪烁体探测器的新读出技术，提供了潜在的飞跃性变化（LHe，LHe，LAr），并在许多非PPAN领域有应用，如生命科学中的UV成像技术和作为量子技术的低噪声读出。大多数市售SNSPD器件都以红外波长为目标，虽然有一些UV型号，但它们并没有针对178 nm VUV紫外光进行优化。该项目汇集了英国在LIPE * 探测器方面的专业知识，以及世界一流的SNSPD设计和制造能力，以提供VUV敏感SNSPD器件的原理验证演示，并开发跨PPAN，量子技术和生命科学的一系列新应用。由于其固有的可扩展性，基于英国 * 领先的LXe技术的暗物质探测器已经引领了十多年的中等质量暗物质搜索。除了严格的目标质量和严格的放射性纯度要求外，提高低能量信号灵敏度的关键驱动因素是检测175 nm VUV闪烁光的效率。在这些波长下，诸如VUV* 敏感光电倍增管（PMT）和Si光电倍增管（SiPM）的传统读出装置实现25- 35%QE，并且因此具有> 90%QE SNSPD的读出将是显著的改进。在多个光电传感器上检测到三重符合闪烁信号的典型要求意味着这将导致低质量暗物质和8-硼太阳中微子的信号效率增加一个数量级。该项目的主要目标是证明VUV* 敏感SNSPD设备的可行性，并建立可行性和开发利用这种新功能的案例，包括它们用于紧凑型基于粒子探测器的读出，VUV荧光光谱和离子阱量子计算机。该项目将采用一种分阶段的方法来验证现有的SNSPD探测器，该探测器是由格拉斯哥大学的Hadfield教授的小组开发的：首先，使用双符合维斯（400 nm）事件作为代理来验证SNSPD对VUV信号的性能;然后，使用VUV SiPM器件来表征耐溶剂光纤中的VUV透射率;这将使得SNSPD装置能够首先耦合到单色光源，然后耦合到单色闪烁单元，以完成表征。

With near-unity quantum efficiencies (QE), ultra-low dark count rates down to 10-4 Hz/device and exquisite sub-10-ps-timing resolution, Superconducting Nanowire Single Photon Detectors (SNSPDs) with vacuum-ultraviolet (VUV) sensitivity offer a potential step change as a new readout technology for a broad range of scintillator detectors used by the PPAN community (LXe, LHe, LAr) and have application in many non-PPAN areas, such as UV imaging techniques in the life sciences and as a low-noise readout for quantum technology. Most commercially available SNSPD devices target infrared wavelengths, and whilst some UV models are available they are not optimised for 178 nm VUV Xe light. This project brings together UK expertise in LXe*detectors with world-class capability in SNSPD design and fabrication, to deliver a proof-of-principle demonstration of a VUV-sensitive SNSPD device and to develop a range of novel applications across PPAN, quantum technology and the life sciences that are enabled by this new capability. Due to its inherent scalability, dark matter detectors based on the UK*pioneered LXe-technology have led the search for intermediate-mass dark matter for more than a decade. Alongside Xe target mass and stringent radiopurity requirements, the key driver for improved sensitivity for low*energy signals is the efficiency with which the 175 nm VUV scintillation light is detected. At these wavelengths, traditional readout devices such as VUV*sensitive photomultiplier tubes (PMTs) and Si-photomultipliers (SiPM) achieve 25-35% QE and as such readout with a > 90% QE SNSPD would be a significant improvement. The typical requirement of a triple-coincidence scintillation signal detected across multiple photosensors means this would result in an order of magnitude increase in signal efficiency for low mass dark matter and 8-Boron solar neutrinos. The key objectives of this project are to demonstrate the viability of a VUV*sensitive SNSPD device and to establish the feasibility and develop cases that leverage this new capability, including their use for readout of compact Xe*based particle detectors, VUV fluorescence spectroscopy, and ion-trap quantum computers. The project will follow a staged approach to characterise existing SNSPD detectors developed by Prof. Hadfield's group at the University of Glasgow: first, demonstrate the performance of the SNSPD to a VUV signal using double-coincident VIS (400 nm) events as a proxy; then the characterisation of VUV transmittance in solarisation-resistant optical fibres using VUV SiPM devices; which will enable coupling the SNSPD device, first to a monochromatic light source and then to a Xe scintillation cell for complete characterisation.