一种新型电荷灵敏前置放大器和成形峰保持混合电路

本文介绍一种我们研制的新型电荷灵敏前置放大器和成形放大与峰保持混合电路,该电路采用了新的设计方案,它采用电荷灵敏前置放大器将探测器信号预放大后,再经过放大成形和峰值保持,以便后继电路采样和进行数据的处理.放大器信号成形时间为0.5 μs;1μs;2μs三档可调,放大倍数为×10;×100两档选择,峰保持时间为6μs,它具有噪声低;体积小;电路结构简单;价格低等特点,并且对整个电路做了较详细的阐述.     

一种新颖的激光窄脉冲峰值保持方法与电路实现

首次提出了一种新颖的窄脉冲峰值保持方法.其原理是在脉冲激励下形成衰减振荡波,由峰值包络检波后的电流向电容器充电,最终在电容器上保持脉冲峰值信息.该方法解决了保持电容的充电时间常数完全依赖于脉冲宽度的问题.介绍了工作原理,给出了实现电路和实验结果.该电路结构简单、可靠性好,已经在高精度无协作目标激光脉冲测距仪中应用.     

脉冲峰值保持器的设计方法与元件选择

从峰值保持器的原理出发,从理论上导出了放大器的转换速度、输出电流及保持电容与输入脉冲的上升时间、动态范围的数学式,分析了峰值保持器的主要性能,介绍了放大器和保持电容的选择方法,用OPA615芯片设计了一种高速脉冲峰值保持器.     

窄脉冲信号峰值保持器

介绍一种窄脉冲信号峰值保持器,采用跨导型放大器,可对窄脉宽(10ns～250ns)、重频(单脉冲到kHz)的脉冲信号进行峰值检测.通过spice模型仿真和实际电路测量,表明该电路具有动态范围大、非线性小等特点.     

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.     

开关电容阵列中高带宽跨阻前置放大器设计

为了放大高能粒子物理实验中高精度定时信号,使其适用于开关电容阵列电路的采集范围与幅度,设计高带宽RGC型跨阻前置放大器.此放大器具有低输入阻抗,高带宽,高跨导的特点.采用TSMC 0.25μmCMOS工艺,2.5V单电源供电.仿真结果表明,该前置放大器跨阻增益为5K欧姆,-3dB带宽为953MHz,探测器输入电容在一定范围变化对带宽影响不大.     

一种高速宽带放大与峰值保持电路的研制

主要介绍了一种高速宽带放大与峰值保持电路.该电路是根据束流位置监测系统的要求而研制的,是该系统的前端部分.主要包括放大电路和峰值保持电路两部分,其主要特点是采用直流耦合的方式对微弱快电压信号进行多级放大,使得信号在放大过程中不会产生附加相移,此外还采取差分放大的方式来有效地抑制直流耦合带来的直流漂移.电路带宽≥70MHz,增益≥700.     

基于阻容低通反馈的电荷灵敏前置放大器的设计

传统电荷灵敏前置放大器以高阻值电阻作为低频反馈端,高阻值电阻所引入的热噪声为前置放大器噪声的主要来源。本文以N沟道结型场效应晶体管和阻容(Resistor-Capacitance,RC)电路构成低通网络代替传统高阻值反馈电阻完成了新型电荷灵敏前置放大器的研制。该电路以结型场效应晶体管和集成运算放大器构成放大电路,具有高输入阻抗及大开环增益的优点;以小容值电容构成高通回路,为电路提供高频反馈回路,同时实现核脉冲电流的积分;以RC低通网络构成直流反馈回路,为电路提供一个稳定的直流工作点,同时构成电压分压器使N沟道结型场效应管工作在正向偏置状态,实现对反馈电容中的电荷进行连续放电。相比于传统阻容反馈式电荷灵敏放大器,该电路能够有效克服大阻值反馈电阻引入的噪声,尤其适用于Si-PIN等半导体探测器。将该电荷灵敏前置放大器与BPX66型Si-PIN探测器连接,在室温下对241Am源进行测量,其能量分辨率可达到3.03%@59.5 keV。     

模拟电路的单粒子瞬时效应

综合介绍一种新的单粒子作用现象.模拟电路在单个重离子撞击下,在输出端产生瞬时信号,这种瞬时扰动可能影响到连接模拟电路输出端的电路,例如运算放大器的输出可能连接到数字计数器的输入端,由重离子引起放大器足够大的瞬时输出脉冲可能增加计数器的计数.另外,这种输出端的瞬时电压信号可能改变其它电路的状态.     

一种简单的峰值保持电路

介绍了一种峰值电压采样保持电路工作原理,以两片采样保持芯片LF398和一块LM211比较器构成,具有保持峰值电压和泄放电压的功能。给出了实验结果。该电路结构简单,调试方便。     

共面栅碲锌镉探测器读出电路设计及性能研究

为有效读出共面栅碲锌镉(CPG-CZT)探测器的核脉冲信号，本文结合CPG-CZT探测器工作原理及国内外研究，设计了可用于CPG-CZT探测器的读出电路，主要包括高压偏置电路、前置放大电路、增益调节及减法电路。为研究读出电路性能，本文测试了各单元电路的性能及探测系统能量分辨率随偏置电压、增益调节电路中两路信号的相对增益G的变化规律。结果表明：高压偏置电路两路输出偏压与输入偏置电压的相关系数R²均为0.998；前置放大电路输出噪声为5 mV；增益调节及减法电路输出信号噪声为10 mV；输入偏置电压、相对增益G的变化均会影响探测系统能量分辨率，当偏置电压为-1650 V、相对增益G为0.7时对¹³⁷Cs源产生的γ射线能量分辨率最佳，可达3.65%，且无明显拖尾现象。     

空间单粒子翻转甄别与定位系统原理样机的设计及试验

单粒子翻转（SEU）是影响空间电子设备可靠性的重要因素,本文提出了一种SEU甄别与定位技术方法,研制了原理样机。硅探测器与辐照敏感器件在垂直方向相互临近安装,粒子入射到硅探测器的位置区域与目标辐照器件单粒子翻转的物理位置相对应。采用波形数字化技术实现了多道粒子甄别与能量信号测量,通过数据回读比较法实现了SRAM器件翻转逻辑定位检测。根据实验室测试和单粒子辐照试验结果,可探测高能粒子的LET≥6?06×10-3 MeV·cm2/mg,入射粒子的位置分辨率优于5 mm,最大计数率≥10 000 s-1,SRAM器件的SEU巡检周期时间分辨率为13?76 ms。通过掌握大容量SRAM型器件的SEU甄别与定位及其辐射环境感知能力,有助于提升空间电子设备的在轨工作性能。     

Experimental study of a single tube high RF power amplifier for ICRF heating system

A concept of a single tube high RF power amplifier was developed for ion cyclotron range of frequency (ICRF) plasma heating system. In the concept, a tetrode was used with a grounded cathode and input power to drive a control grid of the tetrode was provided by a switching circuit. As the new amplifier arrangement can eliminate a low power (10 kW level) and an intermediate power (100 kW level) tetrode amplifiers, their high voltage DC (HVDC) power supplies, and control and monitor system for these amplifiers and HVDC power supplies in a conventional high RF power source of the ICRF heating system, this new high RF power source is more flexible on frequency change and more mechanically reliable than the conventional one. A test amplifier composed of the tetrode and a field effect transistor (FET) switching circuit was constructed. The FET switching circuit was so compact that it could be mounted close to the tetrode socket. The maximum output RF power of 8.5 kW was obtained with a plate efficiency of 82% at 70 MHz. The feasibility of the single tube high RF power amplifier was experimentally proved. The plate efficiency of 82% could not be explained by the standard class-C amplification but by high efficiency amplification under assumptions of a flat-topped plate current pattern and double resonance of an output cavity at the fundamental frequency and the third higher harmonic frequency.     

A New Approach to Direct Current Integration

A new all-solid state direct-current integrator integrates currents as low as 10-11 ampere with an accuracy of 1%. The operating principle is similar to that of more conventional current integrators in that the voltage across a storage capacitor in the input circuit is monitored by an electrometer type operational amplifier, the output of which triggers a discriminator at a given voltage level. The discriminator generates a reset pulse which removes a fixed charge from the integrating capacitor. This is where the similarity ends. The diode pump circuit, which has long been recognized as an ideal circuit for removing precise quantities of charge from the integrating capacitor, has been replaced by complementary silicon planar transistors that operate in the inverted-mode and serve as current switches. These transistors normally have both their base-emitter and base-collector junctions reverse biased and look like open switches with leakage currents of about 10-13 ampere. Reset pulses switch these transistors from the reverse-biased state to the active state for a precise time during which a constant current flows to or from the integrating capacitor. Therefore, each reset pulse removes from the integrating capacitor a precise charge that is the product of the current and the period of the active state. By the employment of sufficient gain in the operational amplifier to maintain small voltage excursions at the input, the total effective leakage may be kept as low as 10-14 ampere.     

基于大学核物理实验的数字化MCA的研制

介绍了一种用于大学核物理教学实验的基于FPGA全数字化多道脉冲幅度分析器(MCA)的研制。系统采用全数字化方法对输入的脉冲信号高速数字化,然后送入FPGA进行数字寻峰、记录、谱处理,并在主机上显示。给出了数字寻峰的原理,利用双甄别阈值提高系统的抗干扰能力;针对ADC的非线性对系统造成的影响,研究修正算法,保证数据采样的道宽均匀性;鉴于MCA采样存储的数据量大的特点,采用双RAM并行工作方式,将传输数据和计数存储分开处理,减少死时间及数据的溢出;在终端显示方面,主机通过USB总线实现了系统实时监控和能谱数据传输。通过实验对比了该系统与商用MCA的性能,取得了很好的测试效果。     

微弱光电流信号放大器的设计

针对等离子体物理实验装置托卡马克(EAST)实验中微弱信号的探测需要,结合EAST的恶劣电磁环境以及光电检测电路的基本工作原理,设计了一种实用的光电弱信号电流放大器.电路由前置电流放大器、有源滤波放大电路构成,结合电磁兼容技术对信号进行接地和屏蔽,以及合理布线,旨在保证增益和带宽的同时降低噪声.实验表明,基于本设计的光...     

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X射线探测技术的电路设计

主要研究的是基于X射线探测技术的电路.设计电路中包括了输入级、线性放大电路、脉冲幅度分析电路等.同时也研究了高压电源,高压电源为探测器提供高电压,对X射线能级探测有很大的作用.     

RG64—High Count Rate Low Noise Multichannel ASIC With Energy Window Selection and Continuous Readout Mode

We report on the performance of a low noise and high count rate readout ASIC with binary architecture and energy window selection for X-ray imaging applications using semiconductor detectors. The ASIC called RG64 is designed in 0.35 mum CMOS process and its total area is 3900times5000 mum². The core of RG64 consists of 64 readout channels. Each channel is built of a charge sensitive amplifier with a second order shaper of peaking time 75 ns, two independent discriminators with an 8-bit offset correction circuit and two independent 20-bit counters with RAM memory buffers. The ENC of the circuit reaches the value of about 126 el. rms with 1 pF input load and 5 mW power consumption per single channel. The mean gain in the multichannel ASIC is about 50 muV/el., with the dispersion from channel to channel of 0.9% (on one sigma level). The deviation of the effective threshold voltage spread for given energy can be reduced to less than 7 el. rms (calculated to the charge sensitive amplifier input). High count rate measurements have been performed up to 2 Mcps of average rate of input pulses, both for AC and DC coupled silicon strip detectors with X-ray photons of energy 8.04 keV. The RG64 can operate both in the continuous readout mode and in the readout mode separate from exposure.