一种紧凑的β粒子动量探测器
A compact beta particle momentum detector
AI总结：
本文针对QuIPS实验设计了一款紧凑β粒子动量探测器，采用CMOS追踪器与SiPM读出的塑料闪烁体，实现低能β粒子探测及亚毫米级顶点重建，为中微子动量测量和重惰性中微子搜寻提供关键技术支持。
AI中文摘要：
本文介绍了用于量子不可见粒子传感器（QuIPS）实验的紧凑β电子探测器的设计、研发及首次校准结果。QuIPS电子探测器旨在重建超高真空（UHV）中掺放射性同位素的光镊悬浮纳米球发射的β粒子的完整动量矢量，从而实现中微子动量测量及重惰性中微子搜寻。该探测器包含两个用于方向追踪的薄型CMOS探测器，以及一个由硅光电倍增管（SiPM）读出的塑料闪烁体用于量能。整个组件必须在现有光阱真空腔内部运行，压力低于10^-7 mbar，这对材料选择、功耗、出气率和紧凑性施加了严格约束。我们展示了对能量低至100 keV的β衰变电子的灵敏度，以及在重惰性中微子搜寻的主要感兴趣能区500 keV以上35%的探测效率。CMOS追踪器以毫弧度（mrad）级分辨率解析动量方向，以亚毫米精度重建β发射顶点，而闪烁体-SiPM系统在1 MeV时实现5%的能量分辨率。
英文摘要：
We present the design, development, and first calibration results of a compact beta electron detector for the Quantum Invisible Particle Sensor (QuIPS) experiment. The QuIPS electron detector is designed to reconstruct the full momentum vector of $β$ particles emitted from radioisotope-doped optically levitated nanospheres in ultra-high vacuum (UHV), enabling a measurement of the neutrino momentum and a search for heavy sterile neutrinos. The detector comprises two thinned CMOS detectors for directional tracking and a plastic scintillator read out by silicon photomultipliers (SiPMs) for calorimetry. The entire assembly must operate inside an existing optical trapping vacuum chamber at pressures below $10^{-7}$ mbar, imposing stringent constraints on material selection, power dissipation, outgassing, and compactness. We demonstrate sensitivity to $β$-decay electrons with energies as low as 100 keV and a detection efficiency of 35% above 500 keV, the primary window of interest for a heavy sterile neutrino search. The CMOS tracker resolves the momentum direction at the mrad scale and reconstructs the $β$ emission vertex with sub-mm precision, while the scintillator-SiPM system achieves an energy resolution of 5% at 1 MeV.
