CsI(Tl)晶体的APD前端读出特性研究

雪崩光电二极管(Avalanche photodiode,APD)体积小、探测效率高、内置增益、对磁场不敏感,但其内置增益、输出脉冲信号的信噪比受偏置电压与温度影响明显。将APD作为Cs I(Tl)闪烁晶体的光电读出器件,并配以低噪声的电荷灵敏前置放大器,组成闪烁探测器的探头。在不同的偏置电压与温度下,测试了该探头组成的闪烁探测器的能量分辨率。实测表明,偏置电压、温度将影响探测系统的能量分辨率,在室温且APD两端的偏置电压为370 V时,对能量为662 ke V的γ射线能量分辨率为4.98%;在-20-40oC内,能量分辨率随温度的降低而提高。     

半导体探测器输出电流检测系统前置放大器设计

为满足半导体探测器输出电流检测系统的需求,设计了与之相适应的前置放大器。该前置放大器基于超低偏置电流运放ADA4530,采用单个反馈电阻和T型反馈网络的I/V变换前置放大电路组成。测试结果表明:该前置放大器的放大倍数可达10 mV/pA,直流偏移为8μV;对于pA级分辨率,其输出噪声电压频谱密度仅为17.75 nV/(Hz)~(1/2),输出总噪声为409μV;可用于μA~pA范围内的核辐射探测器电流信号测量。     

CsI(Tl)闪烁探测器读出电路设计

介绍了配置于新型γ能谱仪的CsI(Tl)闪烁探测器的读出电路设计。输入缓冲级采用折叠嵌位电路,改善了系统频率特性并提高了输入阻抗;放大级采用自举电路,改善了系统动态性能并提高了开环增益;输出级采用电流源负载电路,改善了输出信号的线性度并增强了系统的稳定性。实验表明:读出电路噪声为51.08 f C+1.97 f C/p F,时间漂移为0.112%,探头对137Cs源γ射线的输出信号信噪比可达23:1,能量分辨率可达4.98%。     

一种低噪声电荷灵敏前置放大器的研制

介绍了一款新型低噪声电荷灵敏前置放大器的研制。该电荷灵敏前置放大器采用新的自主设计方案,可利用计算机的USB接口直接供电,其电子学等效输入噪声约为0.08 f C,积分非线性为1.8%。该电荷灵敏前置放大器可用于小型半导体核探测谱仪的信号读出放大。集探测器偏置高压、低压电源、电荷灵敏前放、成形电路于一体,体积小、使用方便、噪声低。     

SiPM核辐射探测器电路设计

本文研究基于硅光电倍增管(SiPM)和塑料闪烁体的核辐射探测器电路,设计了适用于SiPM电压偏置电路和信号放大电路,并测试了电路的相关参数:电压偏置电路噪声在5m V以下,放大电路输出信号幅度可达伏级,带宽约为80MHz,最大信噪比在50db左右,四路探测器总功率为0.84W,符合项目设计要求。     

LaBr_3(Ce)闪烁体APD前端读出设计

本文以雪崩光电二极管为小体积Labr_3(Ce)闪烁体的光电读出器件,并设计低噪声电荷灵敏前置放大器与雪崩光电二极管进行匹配组成完整前端探头,可应用于便携式小体积能谱仪中。雪崩光电二极管的增益、暗电流和结电容易受两端偏置电压影响,而这些特性的变化将影响能谱的读出效果。为此在不同的偏置电压下,测试了该探头组成的闪烁探测器的能量分辨率。当偏置电压为380 V时,对能量为662 keV的γ射线的最佳能量分辨为3.97%。     

半导体阵列微剂量探测器前端读出电路设计

根据三维Si SOI PIN像素微剂量探测器特性参数,设计了一种基于GF chrt018IC CMOS工艺的前端读出电路。该读出电路主要包括PMOS输入的电荷灵敏前前置放大器,有源整形滤波电路,电压比较器及基准电流源等,可实现对微剂量信号的放大、滤波降噪、甄别输出等功能。仿真测试表明:能量探测范围为5~500 fC,单通道功耗约为2 mW,总噪声性能为0.05 f C+1.6×10~(-3)fC/pF。     

基于碳化硅探测器的前端信号调理电路设计

碳化硅探测器能够在高温、高辐射强度下稳定工作,适用于核辐射探测。碳化硅探测器输出端连接前端信号调理电路,能够放大碳化硅探测器输出的微弱信号,从而使后端设备采集到准确的数据。设计了前端信号调理电路,包括电荷灵敏前置放大电路和脉冲成形主放大电路,重点分析了影响电荷灵敏前置放大电路变换增益、上升时间、噪声等性能指标的影响因素,采用阻容反馈、极零相消、有源滤波成形等设计提升电路的整体性能。实验室仿核脉冲测试及²⁴¹ Am中子源辐照测试表明,该电路可用于碳化硅探测器的核辐射测量。     

基于3D Si PIN阵列热中子探测器的变增益宽动态前端读出电子学设计

基于Si CMOS技术的前端读出ASIC主要是根据3D Si PIN阵列热中子探测器的输出信号特性设计的。所设计的读出ASIC的主要电路模块包括电荷灵敏放大器（CSA）、模拟开关设计、具有三级电荷灵敏自动转换的自动增益控制模块（AGC）、相关双采样（CDS）和基准电流源电路。仿真结果表明,前端电路的输入动态范围为10 fC~80 pC。根据热中子探测器输出信号特性设计的ASIC的3个增益系数分别为19 V/pC、039 V/pC和94 mV/pC。所设计的ASIC的积分非线性小于 1%。单通道静态功耗约为 536 mW。零输入探测器电容时的等效噪声电荷为2416e-。计数率可达1 MHz 。     

羊八井大型水契伦科夫探测器中双增益大动态范围前放的研制

介绍了羊八井大型水契伦科夫探测器中前置放大器的预研设计,分析了该前放的设计原理,介绍了测试方法和性能指标。该前放接收光电倍增管输出信号,采用双增益和差分输出设计方案。对该前置放大器原型电路的测试结果表明,该前放两通道增益分别为2倍和34倍,-3 dB带宽均大于150MHz,可满足0.5 mV～2 000 mV的输入信号大动态范围及远距离传输信号的实验需求。     

ICON, a current mode preamplifier in CMOS technology for use withhigh rate particle detectors

The ICON current mode preamplifier intended for use in experiments at high-rate hadron colliders is described. The transient response and noise performance are analyzed. One chip has been made using an ICON circuit with resistive feedback to produce a preamplifier with a peaking time of below 10 ns. This fast preamplifier has a gain of 870 mV/pC and a power dissipation of around 1 mW. Another chip was made using the ICON circuit as the front-end to a dual-port analog memory. The noise measured is between 2400 e^- and 3000 e^-. An important characteristic of ICON is that it can tolerate a detector leakage current of 10 μA at the DC-coupled input. Therefore, it is very suitable for silicon detector systems under severe radiation conditions     

基于峰值保持电路的GEM探测器前端读出ASIC设计

介绍了一种用于多层GEM探测器的低噪声前端读出ASIC芯片.针对GEM探测器输出信号特点,设计了电荷灵敏放大器、整形电路和峰值保持电路,并对其噪声、成形时间等设计指标参数进行了分析.     

Design and test results of a low-noise readout integrated circuit for high-energy particle detectors

A low-noise readout integrated circuit for high-energy particle detector is presented.The noise of charge sensitive amplifier was suppressed by using single-side amplifier and resistors as source degeneration.Continuous-time semi-Gaussian filter is chosen to avoid switch noise.The peaking time of pulse shaper and the gain can be programmed to satisfy multi-application.The readout integrated circuit has been designed and fabricated using a 0.35 μm double-poly triple-metal CMOS technology.Test results show the functions of the readout integrated circuit are correct.The equivalent noise charge with no detector connected is 500–700 e in the typical mode,the gain is tunable within 13–130 mV/fC and the peaking time varies from 0.7 to 1.6 μs,in which the average gain is about 20.5 mV/fC,and the linearity reaches 99.2%.     

RX64DTH -a fully integrated 64-channel ASIC for a digital X-ray imaging system with energy window selection

We report on the multichannel IC (RX64DTH) designed for position sensitive X-ray measurements with silicon strip detectors and dedicated to medical imaging applications. This integrated circuit has a binary readout architecture with a double threshold allowing on selection energy window for measured signals. The design was realized in a 0.8 /spl mu/m CMOS process. The core of the RX64DTH IC consists of 64 readout channels. The single channel is built with four basic blocks: charge sensitive preamplifier, shaper, two independent discriminators, and two independent 20-bit counters. Each readout channel counts pulses which are above the low discriminator threshold and counts pulses independently above the high discriminator threshold. The energy resolution in such architecture is limited by the noise of a single channel and by channel to channel threshold spread. We present the noise and matching performance of a 384-channel module built with a silicon strip detector and six RX64DTH ICs. In the 384-channel module an equivalent noise charge of about 200 el. rms is achieved for the shaper peaking time of 0.8 /spl mu/s and strip capacitance of 3 pF. The deviation of discriminator thresholds for the whole system is only 87 el. rms. The obtained results show that the energy resolution and uniformity of analog parameters (noise, gain, offset) are sufficient for medical diagnostic applications such as dual energy mammography and angiography.     

Characteristics of 16-Channel ASIC Preamplifier Board for Microstrip Gas Chamber and Animal PET

A 16-channel ASIC preamplifier board has been designed for microstrip gas chamber (MSGC) and animal position emission tomography (PET) detectors. The highly integrated ASIC chips can be used for individual readouts from a large number of channels to improve the spatial resolution and counting rate. The preamplifier board was tested to have a low optimum equivalent noise charge (ENC) of ~ 1400 e^? FWHM at a shaping time of 0.1 μs. The output voltage to input charge gain is 0.96 V/pC, and the nonlinearity is ~ 2:0% over a range of ?500 fC to 1000 fC in input charge. The rise time (10%–90%) with no input capacitor is about 54 ns. The power consumption of this preamplifier board is ~ 100 mW. The preamplifier board has been used to read out a 3 × 3 cm MSGC plate and an optimum FWHM energy resolution of 19.1% (5.9 keV peak of Fe-55) was obtained.