原子能科学技术2025，Vol.59Issue(3)：717-724,8.DOI:10.7538/yzk.2024.youxian.0553
基于同轴型高纯锗探测器的CMOS电荷灵敏前置放大器设计
Design of CMOS Charge-sensitive Amplifier for Coaxial High Purity Germanium Detector
摘要
Abstract
High purity germanium detectors play an increasingly significant role in particle physics and astrophysics,particularly in low-background radiation measurement experiments,due to their exceptional energy resolution,high detection efficiency.These detectors are especially critical in the search for rare events,such as neutrinoless double-beta decay(0vββ)and direct detection of dark matter,as they operate effectively under extremely low-background conditions.To fully leverage the advantages of HPGe detectors,a specifically tailored front-end readout system was required to minimize the contribution of electronic noise from the system itself.This noise minimization is critical to ensure that weak event signals from inside the detector are not obscured by the system's inherent noise.In this paper,the design of a multi-channel,low-noise charge-sensitive amplifier(CSA)optimized for use with coaxial HPGe detectors was proposed,particularly those with large input capacitance.Large-capacitance detectors tend to introduce significant input noise,which degrades the overall energy resolution of the system.Therefore,higher standards are necessary for the noise performance of front-end electronics in such systems to preserve the excellent resolution that HPGe detectors can achieve.In multi-stage amplification systems,the noise performance is primarily influenced by the first amplification stage,where the noise characteristics of the input transistor play a crucial role.To address this,the input transistor was designed using an optimized noise model,iterative simulations,and a specially engineered layout structure to ensure low noise.However,larger transistor sizes can lead to gate leakage currents,which can alter the baseline of the amplifier output.To address this issue,a low-noise CSA circuit with a feedback resistor module for leakage current compensation was developed.This resistor feedback module mitigates sensitivity to power supply variations,temperature changes,and process deviations,and can compensate for leakage currents up to several micro amperes.Importantly,the circuit is self-biased,eliminating the need for external bias to adjust the feedback resistance value.The proposed amplifier demonstrated a rise time of less than 50 ns when used with a detector capacitance of 10 pF,and no oscillations were observed under these conditions.At low temperatures,the amplifier exhibits outstanding noise performance,with a noise level as low as 5.6 electrons.Additionally,it provides an output conversion gain of 5 mV/fC,a linearity deviation of only 0.15%,and a low static power consumption of 12.5 milliwatts.The performance achieved is sufficient for gamma-ray spectroscopy and pulse shape analysis using coaxial high purity germanium detectors.关键词
高纯锗探测器/电荷灵敏前置放大器/低噪声/集成电路设计Key words
high purity germanium detector/charge-sensitive amplifier/low noise/integrated circuit design分类
能源科技引用本文复制引用
刘崭,何高魁,刘海峰..基于同轴型高纯锗探测器的CMOS电荷灵敏前置放大器设计[J].原子能科学技术,2025,59(3):717-724,8.基金项目
国防科工局核能开发科研项目(HNKF202224(28)) （HNKF202224(28）
