一种基于Si-APD的X射线单光子探测电路设计  

Design of the X-ray Single Photon Detection Circuit Based on Si-APD

作　　者：董龙[1] 傅丹膺[2] 龚志鹏[1] 

机构地区：[1]北京空间机电研究所,北京100094 [2]中国空间技术研究院,北京100094

出　　处：《航天返回与遥感》2016年第1期55-62,共8页Spacecraft Recovery & Remote Sensing

摘　　要：X射线单光子探测电路是将入射X射线单光子转换成电信号,进而测量入射光子到达时间和能谱特性的电路,是X射线脉冲星导航的关键技术之一。文章通过分析X射线脉冲星的辐射特性提出了一种基于硅-雪崩光电二极管(Si-APD)的探测电路,Si-APD探测器通过外置偏置高压对入射X射线单光子电离出来的电子进行雪崩放大,偏置电压随着温度的变化自动调节,保证Si-APD增益的稳定性。雪崩抑制电路的作用是对探测器进行复位以探测下一个X射线单光子,文章给出了雪崩抑制电路的工作原理和设计方法,并进一步讨论了在单光子探测应用条件下的前置放大电路和主放大电路设计,合理设计电荷灵敏前置放大器是实现电流电压转换、高增益、低噪声和高时间精度的关键技术,整形带通主放大器作为Si-APD的放大电路,设计合适的带宽和增益可以提高系统信噪比、稳定性、时间分辨率和能谱测量精度。该电路相比于正比计数器、硅漂移探测电路等,具有体积质量较小、可靠性高、造价低廉等优点,可实现高速、高信噪比的X射线单光子探测电路设计。X-ray photons can be converted into electrons by a circuit of X-ray single photon detection, so that the arrival time and the energy spectrum of the photons are measured. This kind of circuit is one of the key techniques of X-ray pulsar-based navigation. After analyzing the radiation characteristic of X-ray Pulsar, a de- tection circuit using Si-APD is designed, in which the Si-APD detector provides electrons from avalanche io- nization caused by the single incident X-ray photon. The detector is controlled by external offset high-voltage. The automatic regulation of the bias voltage along with the temperature ensures the gain stability of the Si-APD The avalanche quenching circuit is designed as well to reset the detector for the next detection. The operating principle and the designing method are introduced. Furthermore, the design of preamplifier and main amplifier in the certain conditions of single photon detection is discussed. A reasonable design of Charge-sousiltive preamplifier is the key point to implement the switch from voltage to current, high gain, low noise and high time precision. Proper band with and gain designed of the shaping band-pass main-amplifier are helpful in im- proving SNR, stability, time resolution and spectrum measurement precision. Compared with proportional counter and silicon drift detector（SDD）, this kind of circuit not only achieves high speed and high SNR for de- signing the circuit of X-ray single photon detection but also has lighter weight, smaller size, higher reliabilityand less cost.

关 键 词：雪崩光电二极管 X射线 单光子探测 电路设计 脉冲星导航 

分 类 号：TN202[电子电信—物理电子学]