STCF RICH原型探测器的测试电子学系统构建与联调测试

环形成像切伦科夫（RICH）探测器作为超级陶粲装置（STCF）带电强子(π/K/p)鉴别的技术选项之一,采用厚型气体电子倍增器+微网格气体（THGEM+Micromegas）混合探测器结构以实现对切伦科夫光的探测。针对RICH原型探测器的信号读出,构建了一套1 024通道测试电子学系统,并与探测器进行了联合测试。该测试电子学系统使用高密接插件与RICH原型探测器进行连接,探测器输出信号通过测试电子学系统上的AGET和ADC芯片进行放大、成形和波形数字化,输出的数据经FPGA处理后通过千兆以太网传输至后端PC并进行数据分析。测试结果表明,在120 fC输入动态范围下,系统的等效噪声电荷（ENC）小于0.3 fC,且具有良好的输入-输出线性。该系统成功应用于RICH原型探测器切伦科夫成像束流实验中,并取得了良好的切伦科夫光成像结果。     

STCF RICH原型探测器的测试电子学系统构建与联调测试

环形成像切伦科夫(RICH)探测器作为超级陶粲装置(STCF)带电强子(π/K/p)鉴别的技术选项之一,采用厚型气体电子倍增器+微网格气体(THGEM+Micromegas)混合探测器结构以实现对切伦科夫光的探测。针对RICH原型探测器的信号读出,构建了一套1 024通道测试电子学系统,并与探测器进行了联合测试。该测试电子学系统使用高密接插件与RICH原型探测器进行连接,探测器输出信号通过测试电子学系统上的AGET和ADC芯片进行放大、成形和波形数字化,输出的数据经FPGA处理后通过千兆以太网传输至后端PC并进行数据分析。测试结果表明,在120 fC输入动态范围下,系统的等效噪声电荷(ENC)小于0.3 fC,且具有良好的输入-输出线性。该系统成功应用于RICH原型探测器切伦科夫成像束流实验中,并取得了良好的切伦科夫光成像结果。     

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.     

微结构气体探测器多通道高速读出系统研制

本文设计并实测了用于多通道微结构气体探测器信号读出的512通道电子学系统。该系统以Spartan-6 FPGA作为控制和数据处理核心,使用4通道ADC芯片对4片APV25芯片的输出信号进行同步模数转换,经千兆以太网发送命令和传输数据,计算机端则以双线程分别接收和发送数据。实测输入电容低于200 pF时,系统噪声低于2000e,有效电荷输入范围为±20 fC,12 fC以下时线性良好。经长时间测试,系统稳定可靠,千兆网数据传输速率可达940 Mb/s。单片APV25工作时,连续触发率可达APV25上限285 kHz,4片时则为134 kHz。在实际应用于GEM探测器α射线成像实验中取得了较好的成像结果。     

四通道低噪声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CEM探测器输出信号特点,设计了电荷灵敏放大器、极零相消电路和准高斯成形电路,并对其噪声指标、成形时间等设计指标等参数进行分析.     

大面积GEM中子探测器高计数率读出电子学系统研制

研制并测试了GEM中子探测器的512通道高计数读出电子学系统,以满足中国散裂中子源高效率、高分辨、高通量二维位置灵敏中子探测器的需求。系统以Kintex-7 FPGA作为系统控制和数据分析的核心,使用8块AS20Board前端芯片对灵敏面积为200 mm×200 mm的探测器的两个维度的信号进行读出,读出通道为256×256。读出数据经FPGA分析后通过千兆以太网传输至计算机显示。计算机可通过千兆以太网发送配置指令对前端采样电路和FPGA算法进行配置。系统与探测器组装后在中子束流实验中测得系统最高瞬时计数率为（1.2±0.1）×106 s^-1,系统运行稳定,受噪声干扰小。     

应用于气体电子倍增器的电子学板研制

气体电子倍增器（GEM）电子学板（GEB）在大面积GEM探测器系统中起重要作用。为满足大面积GEM探测器系统中高速电子学信号的传输、实现电磁屏蔽及为前端电子学提供电源等需求,本文设计了8层结构的GEB,并对该GEB原型进行了电气性能、机械兼容性、信号传输和噪声测试。测试结果显示,本文所设计的GEB在320 Mb/s信号传输速度下的误码率小于10^-13,在保证信号高速性和完整性的基础上能成功传输前端电子学信号;通过采用叠层对称式设计克服了大面积GEB生产时弯曲程度高的困难,生产的GEB原型弯曲高度降低了2/3,平均弯曲高度为1 mm,增强了前端电子学在探测器系统中的运行稳定性。     

大面积GEM中子探测器高计数率读出电子学系统研制

研制并测试了GEM中子探测器的512通道高计数读出电子学系统,以满足中国散裂中子源高效率、高分辨、高通量二维位置灵敏中子探测器的需求。系统以Kintex-7 FPGA作为系统控制和数据分析的核心,使用8块AS20Board前端芯片对灵敏面积为200 mm×200 mm的探测器的两个维度的信号进行读出,读出通道为256×256。读出数据经FPGA分析后通过千兆以太网传输至计算机显示。计算机可通过千兆以太网发送配置指令对前端采样电路和FPGA算法进行配置。系统与探测器组装后在中子束流实验中测得系统最高瞬时计数率为(1.2±0.1)×10~6 s~(-1),系统运行稳定,受噪声干扰小。     

应用于气体电子倍增器的电子学板研制

气体电子倍增器(GEM)电子学板(GEB)在大面积GEM探测器系统中起重要作用。为满足大面积GEM探测器系统中高速电子学信号的传输、实现电磁屏蔽及为前端电子学提供电源等需求,本文设计了8层结构的GEB,并对该GEB原型进行了电气性能、机械兼容性、信号传输和噪声测试。测试结果显示,本文所设计的GEB在320 Mb/s信号传输速度下的误码率小于10~(-13),在保证信号高速性和完整性的基础上能成功传输前端电子学信号;通过采用叠层对称式设计克服了大面积GEB生产时弯曲程度高的困难,生产的GEB原型弯曲高度降低了2/3,平均弯曲高度为1 mm,增强了前端电子学在探测器系统中的运行稳定性。     

基于GEM探测器的数字读出芯片研制

研制了一种适用于高能物理GEM探测器读出系统的数字芯片。芯片采用PAD读出方式,对GEM探测器的输出直接采样,对采样到的信号放大并成形,判断该输入是否超过由外部DAC设定的阈值,给出判断结果,并按照一个串行协议读出。芯片采用0.35μm/3.3 V CMOS工艺设计,后仿真结果显示芯片达到预期研制目标。     

A study of gas electron multiplier

A new kind of gas detector based on gas electron multiplier (GEM) is studied for X-ray imaging of high luminosity. A single-GEM device is designed to test the prnperty of GEM foil ,The effective gain and counting capability of a double-GEM detector are measured by an X-ray tube with Cu target. An initial X-ray imaging experiment is carried out using a triple-GEM detcctor and the position iesolution of less than 0.1mm is achieved. The 3D distribution of electrostatic field of GEM mesh is also presented.     

GEM探测器α表面污染监测系统研制

研制了大面积GEM探测器,构建了位置灵敏α表面污染监测系统。该系统主要由GEM膜、多路读出电子学系统、数据获取与展示软件等组成。该系统对α粒子的本征探测效率可达95%以上,并实现了系统对α粒子的位置灵敏成像,可为表面污染类α粒子的精确位置测量提供一种有效手段。     

Clustering Method to Process Signals from a CdZnTe Detector

The poor mobility of holes in a compound semiconductor detector results in the imperfect collection of the primary charge deposited in the detector. Furthermore the fluctuation of the charge loss efficiency due to the change in the hole collection path length seriously degrades the energy resolution of the detector. Since the charge collection efficiency varies with the signal waveform, we can expect the improvement of the energy resolution through a proper waveform signal processing method. We developed a new digital signal processing technique, a clustering method which derives typical patterns containing the information on the real situation inside a detector from measured signals. The obtained typical patterns for the detector are then used for the pattern matching method. Measured signals are classified through analyzing the practical waveform variation due to the charge trapping, the electric field and the crystal defect etc. Signals with similar shape are placed into the same cluster. For each cluster we calculate an average waveform as a reference pattern. Using these reference patterns obtained from all the clusters, we can classify other measured signal waveforms from the same detector. Then signals are independently processed according to the classified category and form corresponding spectra. Finally these spectra are merged into one spectrum by multiplying normalization coefficients. The effectiveness of this method was verified with a CdZnTe detector of 2 mm thick and a ¹³⁷Cs gamma-ray source. The obtained energy resolution was improved to about 8 keV (FWHM). Because the clustering method is only related to the measured waveforms, it can be applied to any type and size of detectors and compatible with any type of filtering methods.     

Integral Type Position-Sensitive Proportional Chamber with Multiplexer Readout System

A new position-sensitive detector with a multiplexer readout system for synchrotron radiation measurements is described. The detector consists of many proportional chamber cells with capacitors for charge accumulation. Charges delivered from a detector cell are accumulated in an associated capacitor during a measuring time. The accumulated charges are transferred to a charge-sensitive amplifier through a multiplexer channel which is addressed by binary coded signals. This process corresponds to the integral type radiation measurement which has no dead time in the pulse measurement. Each cell is regarded as a memory cell containing information about X-ray photons. Experiments carried out with a direct X-ray beam show that the detecting system is applicable to a wide range of photon rates from 103 cps to 108 cps per cell.     

基于APV25读出电子学系统的GEM探测器的位置分辨与X射线成像研究

采用3层GEM膜制作了有效面积为10 cm×10 cm的GEM探测器,该探测器采用二维条读出方式,条间距为400 μm,每个维度有256个读出通道。探测器的读出采用APV25读出电子学系统,根据GEM探测器的需要,设计并改进了电子学系统使用的背板连接器。实验测得GEM探测器空间分辨为76 μm。进行了X射线二维成像研究,获得了清晰的二维图像,探测器与电子学运行稳定可靠。     

磁质谱仪离子收集器数字化读出系统的研制

研制了一个用于磁质谱仪法拉第筒阵列离子收集器的高精度数字化读出系统,实现对离子束中离子成分的分析与诊断。数字化读出系统由前端处理电路和数据获取模块组成,前端处理电路采用门控积分器将418通道微弱电荷信号转换为电压信号,数据获取模块将电压信号数字化后,通过以太网接口将数据上传到远程上位机。该读出系统实现了电荷范围为0.1~120 pC的数字化读出,非线性误差小于1.95%（全量程）。现场应用测试结果表明,该数字化读出系统完全满足实验需求。该系统还可广泛用于核物理实验和加速器系统中微弱电流或电荷信号的测量。     

Bunch-by-bunch longitudinal phase monitor at SSRF

Beam signals captured from a button-type pickup contain multidimensional information including the bunch charge,transverse position,bunch length,and longitudinal phase.A bunch phase monitor,which retrieves longitudinal phase information from a pickup signal at a bunch-by-bunch rate,has been developed at the Shanghai Synchrotron Radiation Facility.This paper introduces the basic principles,system setup,data processing method,and preliminary experimental results of this system.The systematic measurement error introduced by the limited system bandwidth,bunch length,and bunch charge variation was studied using simulation data.The random measurement uncertainty was evaluated using experimental beam data.The experimental result shows that the longitudinal phase resolution of this system is better than 1.0 ps.The first application,measuring the relationship between the longitudinal phase and bunch charge to determine the energy loss factor,was implemented,and the preliminary result is also discussed.