用于低质量暗物质搜寻的二苯乙烯晶体的闪烁特性
Scintillation Properties of a Stilbene Crystal for Low-Mass Dark Matter Searches
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中文总结 AI 辅助
本研究表征溶液生长的反式二苯乙烯晶体的闪烁特性，确定其基线性能，为将其作为低质量暗物质搜寻靶材提供支持。
中文摘要 AI 辅助
直接搜寻低质量弱相互作用大质量粒子（WIMPs）需要对低能核反冲具备灵敏度。含氢靶标具有良好的散射运动学特性，因为低质量WIMPs传递给氢原子核的动能比例远大于传递给更重原子核的比例。反式二苯乙烯（t-stilbene）是一种富氢有机晶体，兼具该运动学优势与高效闪烁性能及脉冲形状甄别（PSD）能力。本研究表征了溶液生长的t-stilbene晶体的闪烁衰减行为与有效光产额，以评估其用于暗物质探测的适用性。探测器由直径约1.1cm、长度约1.1cm的圆柱形晶体构成，两端光学耦合至两个滨松（Hamamatsu）R12669光电倍增管。闪烁波形采用三指数衰减模型描述，得到加权分数的衰减时间常数：快成分8.3±0.2ns、中成分20.1±0.3ns、慢成分74.2±1.1ns。采用²⁴¹Am源的59.54keV γ射线测定的有效光产额为3.37±0.02个光电子/keV。本测量确定了探测器的基线性能，支持进一步评估t-stilbene作为稀有事件及低质量暗物质搜寻靶材的潜力。
英文摘要
Direct searches for low-mass WIMPs require sensitivity to low-energy nuclear recoils. Hydrogen-containing targets offer favorable scattering kinematics because low-mass WIMPs can transfer a larger fraction of their kinetic energy to hydrogen nuclei than to heavier nuclei. Trans-stilbene (t-stilbene) is a hydrogen-rich organic crystal that combines this kinematic advantage with efficient scintillation and pulse-shape discrimination (PSD).In this work, we characterize the scintillation decay behavior and effective light yield of a solution-grown t-stilbene crystal to evaluate its suitability for dark matter detection. The detector consists of a cylindrical crystal approximately 1.1 cm in diameter and 1.1 cm in length, optically coupled at opposite ends to two Hamamatsu R12669 photomultiplier tubes. The scintillation waveforms are described by a triple-exponential decay model, yielding fraction-weighted decay time constants of $8.3 \pm 0.2$ ns (fast), $20.1 \pm 0.3$ ns (medium), and $74.2 \pm 1.1$ ns (slow). The effective light yield, determined using a 59.54 keV $γ$ ray from an $^{241}$Am source, is $3.37 \pm 0.02$ photoelectrons per keV.These measurements establish the baseline performance of the detector and support further evaluation of t-stilbene as a target material for rare-event and low-mass dark matter searches.
