AI 中文总结
本研究制备了两个锂扩散ICPC型HPGe探测器，实现稳定运行，测得其电学与光谱性能良好，为紧凑型HPGe探测器的制备提供了可行方案，明确了非活性层表征的后续研究方向。
AI 中文摘要
低电容、低电子噪声且高压运行稳定的高纯度锗（HPGe）探测器，对高分辨率γ射线光谱学和稀有事例搜索具有重要意义。我们报道了两个紧凑型p型倒同轴点接触（ICPC）HPGe探测器AK01和AK02的制备与表征，这两个探测器由南达科他大学（USD）生长的晶体制成。两个器件均采用锂扩散n+外接触，结合非晶锗/铝点接触电极。本研究的主要进展是在两个独立制备的USD生长ICPC原型上实现了这种混合接触工艺，并验证了其稳定的电学和光谱学运行性能。两个探测器均表现出皮安级漏电流，AK01的工作耗尽电压范围约为200-250V，AK02约为240-260V，估计的有效坪区电容分别约为0.84pF和0.87pF。使用137Cs源进行测量时，在662keV附近，AK01和AK02的存档全能峰半高宽（FWHM）分别为1.71keV和1.62keV；使用241Am源时，AK02在59.5keV处的FWHM为1.04keV。电场计算再现了与测量探测器几何结构相符的预期ICPC场构型。以AK02构建的Geant4模型作为定性响应研究，其0.8mm厚的锂扩散非活性层是示例性模型假设而非实测厚度，其高斯展宽受实验分辨率约束。因此，本研究确立了紧凑型锂扩散ICPC原型的制备与运行方案，同时确定了定量非活性层表征是重要的后续研究方向。
英文摘要
High-purity germanium (HPGe) detectors with low capacitance, low electronic noise, and stable high-voltage operation are important for high-resolution gamma-ray spectroscopy and rare-event searches. We report the fabrication and characterization of two compact p-type inverted coaxial point-contact (ICPC) HPGe detectors, AK01 and AK02, produced from crystals grown at the University of South Dakota. Both devices use lithium-diffused $n^{+}$ outer contacts together with amorphous-Ge/Al point-contact electrodes. The principal advance is the implementation of this hybrid contact process on two independently fabricated USD-grown ICPC prototypes and the demonstration of stable electrical and spectroscopic operation. Both detectors exhibited picoampere-level leakage currents, operational depletion-voltage ranges of approximately 200--250~V (AK01) and 240--260~V (AK02), and estimated effective plateau capacitances of approximately 0.84 and 0.87~pF, respectively. Measurements with a $^{137}$Cs source yielded archived full-energy-peak FWHM values of 1.71 and 1.62~keV near 662~keV for AK01 and AK02, while AK02 yielded 1.04~keV FWHM at 59.5~keV with $^{241}$Am. Electric-field calculations reproduce the expected ICPC field configuration for the measured detector geometry. A Geant4 model of AK02 is used as a qualitative response study; its 0.8-mm Li-diffused inactive layer is an illustrative model assumption rather than a measured thickness, and its Gaussian broadening is constrained by the experimental resolution. The work therefore establishes the fabrication and operation of compact lithium-diffused ICPC prototypes while identifying quantitative inactive-layer characterization as an important next step.
Comments19 pages, 14 figures, and 1 table
