基于国产芯片的硅漂移探测器研发与性能调控机制研究

Research on the Development and Performance Regulation Mechanism of Silicon Drift Detectors Based on Domestic Chips

  • 摘要: 硅漂移探测器(SDD)因具备高能量分辨率、低噪声和快速响应等优势,在高精度探测任务中具有重要应用价值。针对国产SDD在漏电流控制、读出电子学集成度及高通量信号处理等方面存在的性能瓶颈,本研究聚焦核心探测器件的自主攻关,首次报道了基于国产芯片的硅漂移探测器PA150的研发及其特性参数的研究成果。为系统表征该新研制芯片的关键物理指标,搭建了XRF测试系统,深入评估了其能量分辨率、计数率线性响应及多元素识别能力等综合性能。实验重点考察了工作温度与峰值时间(Peaking Time,即信号成形时间常数,决定噪声过滤带宽与脉冲堆积概率之间的平衡)对探测器性能的协同调控机制。结果表明:PA150在5.9 keV处的能量分辨率为143 eV,较同单位自主研发的PA200 Si-PIN探测器提升约25%。进一步的物理机制分析发现,降低温度可有效抑制探测器漏电流引起的并联噪声与热噪声,而调节峰值时间则可实现串联噪声(与峰值时间成反比)和并联噪声(与峰值时间成正比)的极小值平衡。基于此机制,确定了最优参数组合(–23℃配合4 ~ 5 μs峰值时间),使探测器能量分辨率提升至约140 eV,并在保持优良分辨能力的同时实现42.99 kcps的较高计数率;当峰值时间降至1 μs时,计数率可达51.39 kcps。这些性能指标已达到国际商用SDD探测器水平,在XRF应用中展现出优异的特征峰分离能力。通过本工作自主化SDD探测器研发,有效解决了国产XRF设备在复杂基体样品(如土壤)重金属快速筛查中对核心探测器的进口依赖问题,为地质、环境及工业在线检测提供了自主技术方案。

     

    Abstract: Silicon drift detectors (SDD) hold significant application value in high-precision detection tasks due to their inherent advantages of high energy resolution, low noise, and rapid response. Addressing the performance bottlenecks of domestic SDD concerning leakage current control, readout electronics integration, and high-throughput signal processing, this study focuses on the independent research and development of core detection devices. Herein, we report for the first time the development and systematic parameter characterization of PA150, an SDD based on a domestically produced chip. To comprehensively characterize the key physical specifications of this newly developed chip, an X-ray fluorescence (XRF) testing system was constructed to conduct an in-depth evaluation of its comprehensive performance, including energy resolution, count-rate linear response, and multi-element identification capabilities. The experiment investigated the synergistic modulation mechanism of operating temperature and peaking time—the signal shaping time constant, which determines the balance between noise filtering bandwidth and pulse pile-up probability—on detector performance. The results indicate that the PA150 achieves an energy resolution of 143 eV at 5.9 keV, representing an improvement of approximately 25% compared to the PA200 Si-PIN detector independently developed by our institute. Furthermore, physical mechanism analysis reveals that lowering the operating temperature effectively suppresses the parallel noise and thermal noise induced by the detector's leakage current. Meanwhile, adjusting the peaking time achieves a minimum-value balance between series noise (which is inversely proportional to time) and parallel noise (which is directly proportional to time). Based on the optimal parameter combination determined by this mechanism (–23℃ coupled with a 4–5 μs peaking time), the detector’s energy resolution is further improved to approximately 140 eV, achieving a high count rate of 42.99 kcps while maintaining excellent resolving capabilities. When the peaking time is reduced to 1 μs, the count rate reaches 51.39 kcps. These performance metrics are comparable to those of international commercial SDD, demonstrating exceptional characteristic peak separation capabilities in XRF applications. The independent development of this SDD effectively resolves the reliance on imported core detectors for the rapid screening of complex matrix samples (such as heavy metals in soil) by domestic XRF equipment, providing an indigenous technological solution for geological, environmental, and industrial online inspections.

     

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