A Path to Superconducting Nanowire Readout of Xe- based detectors

具有近单位量子效率(QE)、低至10-4赫兹/器件的超低暗计数速率和精致的亚10-ps计时分辨率，具有真空-紫外线(VUV)灵敏度的超导纳米线单光子探测器(SNSPD)为PPAN社区使用的各种闪烁探测器(LXE、LHe、LAR)提供了一种潜在的阶跃变化，并已应用于许多非PAN领域，如生命科学中的UV成像技术和量子技术的低噪声读出。大多数商业上可用的SNSPD设备都是针对红外波长的，虽然有一些UV型号可用，但它们并没有针对178 nm的VUV Xe光进行优化。该项目汇集了英国在LXE*探测器方面的专业知识，在SNSPD设计和制造方面具有世界一流的能力，以提供对VUV敏感的SNSPD设备的原理验证演示，并开发一系列由这一新功能支持的跨PPAN、量子技术和生命科学的新型应用。由于其固有的可扩展性，基于英国*首创的LXE技术的暗物质探测器十多年来一直引领着对中等质量暗物质的搜索。除了氙靶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，VUV*敏感光电倍增管(PMT)和硅光电倍增管(SiPM)等传统读出设备可以达到25%-35%的QE，因此使用90%QE SNSPD读出将是一个显著的改进。通过多个光电探测器探测到的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提高一个数量级。该项目的主要目标是展示VUV*敏感SNSPD设备的可行性，并建立可行性并开发利用这一新功能的案例，包括用于读出基于紧凑型Xe*的粒子探测器、VUV荧光光谱和离子陷阱量子计算机。该项目将遵循格拉斯哥大学Hadfield教授团队开发的分阶段方法来表征现有的SNSPD探测器：首先，使用双重合可见光(400 Nm)事件作为代理，展示SNSPD对VUV信号的性能；然后使用VUV SiPM器件表征耐日晒光纤中的VUV透过率；这将使SNSPD设备能够首先耦合到单色光源，然后耦合到Xe闪烁室进行完整表征。

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.