小单元多丝漂移室探测器系统研制

为精确测量CSR外靶终端靶前入射粒子的径迹,研制了多套小单元多丝漂移室探测器,该探测器灵敏面积为80 mm×80 mm,每套探测器包括x、x′、y、y′4个探测电极面,每个电极面引出16个阳极丝信号。前端电子学采用基于SFE16芯片的放大器,数据读出系统采用基于HPTDC芯片的数据采集卡。采用两套小单元多丝漂移室对400 MeV/u的¹⁶O束流位置进行了测试,探测器的工作气体为Ar(80%)+CO₂(20%),阳极丝电压为+900 V,场丝与阴极丝均接地,拟合得到的单层电极的位置分辨(拟合残差)为105.9μm,探测效率为99.3%,该指标可以满足现阶段CSR外靶终端大部分核物理实验对反应靶点的定位要求。     

BESⅢ主漂移室模拟真实化调试研究

以BESⅢ上开发的主漂移室模拟软件为基础,仔细研究并建立了一套规范、有效的主漂移室模拟真实化调试方法。该方法基于对主漂移室响应机制以及真实数据中探测器工作状态的深入理解,建立恰当的参数化模型,通过调试丝击中效率及丝空间分辨,实现主漂移室模拟真实化。论文介绍了BESⅢ主漂移室模拟真实化调试的原理、利用真实数据进行调试的过程以及调试的性能表现。采用这套调试方法,通过调试丝击中效率和空间分辨可以获得恰当的探测器模拟输入参数,使模拟数据与真实数据径迹重建效率的差异达到1%的水平。     

粒子描迹仪系统触发电路及其空间分辨的研究

中国科学院高能物理研究所试验束粒子描迹仪系统用三个多丝正比室(MWPC)做探测器描绘粒子飞行的径迹。本文分析了MWPC输出信号的特点,介绍MWPC阳极信号的前端触发(Trigger)电路及符合电路的原理、设计,并用该电路做触发得到MWPC的空间分辨。符合单元按照核仪器标准设计可作为标准核仪器模块(NIM插件)使用,对3个MWPC的阳极Trigger信号做符合运算,输出的NIM电平提供给数据采集系统做门控(GATE)信号。     

高速实时一维阵列光电探测系统

设计实现了基于PIN光电二极管一维阵列的紧凑型实时光电探测系统。系统在16 cm的宽度内实现了32路PIN光电二极管信号的处理与采样;探测器弱电流信号的高带宽调制电路在实现104倍信号增益的同时,信号带宽约35 MHz;多通道ADC电路采样频率75 MHz,采样周期约13.3 ns,采样精度12 bits;基于高性能FPGA的信号处理电路实现了对32路高速ADC采样信号的实时处理,数据处理速度达到28.8 Gbps,每通道采样深度8 000。     

基于SiPM的乳腺专用PET探测模块研制与评价

基于单点型硅光电倍增管(Si PM)与LYSO闪烁晶体,研制了一种新型乳腺专用PET探测模块,并对其性能进行研究。该探测模块采用28×28根1.9 mm×1.9 mm×15 mm的LYSO晶体组成阵列,与8×8个单点型Si PM组成的阵列通过光导耦合,所产生的脉冲信号分别经过模拟、定时电路处理后送入高速采样电路完成信号处理。该探测模块能够实现1.9 mm位置分辨,12.73%平均能量分辨以及2.66 ns双探头符合时间分辨,具有较好的分辨性能,能够满足乳腺专用PET成像的设计需求。     

一维位置灵敏电阻阳极低能量离子探测器

本文论述了微通道电阻阳极低能重离子探测器的原理，给出了已研制成功的位敏电阻阳极离子探测器的结构和信号分析电子学线路，用＾２３８Ｐｕα放射源测量了位敏探测器在有效面积范围内的位置信号，位置线性和位置分辨。位置分辨好于０．３ｍｍ，已满足了离子原碰撞的实验要求。     

缪子成像系统中二维位置分辨探测器研制

介绍了一种应用于缪子成像系统的新型二维高位置分辨探测器,MRPC探测器的有效面积为1 072 mm×1 072 mm,先后对探测器在宇宙线和X射线下测试其性能,结果表明探测效率高于98%,位置分辨好于272μm。     

兰州重离子储存环外靶实验终端时间投影室的动量分辨率模拟

时间投影室(Time Projection Chamber,TPC)是在多丝正比室(Multi Wire Proportional Chamber,MWPC)和多丝漂移室(Multi Wire Drift Chamber,MWDC)的基础上发展起来的一种高空间分辨粒子径迹探测器。因其具有很高的位置分辨能力,从而可以获得很好的动量分辨率。在开展兰州重离子储存环外靶实验终端CEE(Cooler-Storage-Ring External-target Experiment)-TPC的建造之前,估算CEE-TPC的动量分辨能力是一项很有必要的工作。基于Geant4和Kalman Filter等模拟程序,对时间投影室探测器测量带电粒子的整个过程进行了蒙特卡罗模拟,给出了CEE-TPC探测不同种类的带电粒子的动量分辨率,并且对影响探测器动量分辨率的因素进行了分析。通过模拟计算,得到了CEE-TPC对?介子、质子和氘核的典型动量分辨率在5%左右,能够较好地鉴别这三种粒子,为未来CEE-TPC的建造提供了可供参考的技术参数。     

硅漂移探测器时间分辨优化仿真研究

硅漂移探测器(Silicon Drift Detector,SDD)中电荷包的漂移时间(μs·cm?1)与粒子入射位置到读出电极距离有关,而且通常不能直接测量,其不确定性是影响探测器时间分辨的主要原因.漂移时间和电荷灵敏放大器(Charge Sensitive Amplifier,CSA)输出信号上升时间之间有明显的对...     

小型圆柱漂移室的幅度特性研究

一、引言 在高能对撞机物理实验中,经常使用圆柱漂移室。它围绕在束流管的周围,用来测量对撞产生的带电粒子的径迹。径迹的φ向和径向坐标由信号丝的位置和漂移时间决定,轴向坐标,对于小型圆柱漂移室,通常由电荷分配法求出。为了便于电子学读出,提高时间和电荷测量的精度,要求各信号丝的气体放大系数比较一致。但是,小型圆柱漂移室最靠近内壁和外壁的漂移单元结构与中间各层往往不同,导致信号幅度与中间各层的差异比较大。我们在北京谱仪中心漂移室的预研究过程中,建造了一个4层128根信号丝的小型两维     

Optimal Optical Conditions and Positioning Scheme for an Ultrahigh-Resolution Silicon Drift Detector-Based Gamma Camera

In this study, we optimized the optical conditions and associated positioning scheme for an ultrahighspatial-resolution, solid-state gamma detector. The detector module consisted of an array of seven hexagonal silicon drift detectors (SDDs) packed hexagonally and coupled to a single slab of crystal via a light guide glass. Because the optical behavior and requirements of the detector module and noise characteristics of the SDD sensor are different from those of conventional photomultiplier tube (PMT)-based detectors, the following parameters were studied to determine the optimum condition: scintillator selection, the effect of cooling on signal-to-noise ratio (SNR), the depth dependence of the scintillation light distribution, and optimum shaping time. To that end, a modified, Anger-style positioning algorithm with a denoise scheme was also developed to address the estimation bias (pincushion distortion) caused by the excessively confined light distribution and the leakage current induced by the SDD sensor. The results of this study proved that the positioning algorithm, together with the optimized optical configuration of the detector module, improves the positioning accuracy of the prototype detector. Our results confirmed the ability of the prototype to achieve a spatial resolution of about 0.7mm in full width at half maximum (FWHM) for 122 keV gamma rays under the equivalent noise count (ENC) of 100 (e- rms) per SDD channel. The results also confirmed NaI(Tl) to be a more desirable scintillator for our prototype with an energy resolution performance of about 8%.     

基于GAGG:Ce晶体耦合SiPM的位置灵敏探测器的设计与评估

为满足当前γ相机对高分辨率、低成本、小型化探测器的需求,提出了采用硅光电倍增管（SiPM）耦合GAGG:Ce晶体阵列的方式代替传统的位置灵敏型光电倍增管（PSPMT）耦合晶体阵列的方式以构成新型γ相机探测器,并设计了均匀电荷分配电路（SCDC）和阻抗电桥电路作为探测器的读出电路,同时设计了前沿定时电路作为数据采集触发电路。实验结果表明：当温度为25 ℃、探测器供电电压为28.5 V时,该探测器在511 keV射线的激发下,散点图的峰谷比高达3.84,对511 keV和662 keV射线的平均能量分辨率分别为10.63%和9.71%,具有较好的分辨性能。     

新型望远镜带电粒子探测系统结构设计与理论模拟

为了在兰州重离子加速器国家实验室(HIRFL)的放射性束流线(RIBLL1)上开展基于完全运动学测量的远离β稳定线奇异核反应机制的研究,需研制一套由多个独立的望远镜系统(探测模块)组成的带电粒子探测阵列。每个探测模块包含1块16×16的厚65μm的双面硅条探测器、1块4×4的厚1 000μm的像素硅探测器和由雪崩光二极管(APD)读出的4×4CsI(Tl)阵列探测器。该探测阵列可实现大的能量测量范围、高能量分辨率和位置分辨,同时具备大立体角覆盖和粒子关联测量的能力。通过Geant4探测器模拟软件对单个探测模块进行模拟,结合对探测模块各部分的实验测试,给出了探测模块的设计方案和整体性能指标。     

RIBLL终端LASCAR阵列探测器PMT高压控制系统的研制

介绍了RIBLL终端LASCAR上PMT阵列电源高压控制系统。该系统以当今工程控制中常用的微型计算机作为核心器件,采用合适的外围电路达到了对PMT阵列稳定、可靠的控制,在现场测试中取得了良好的效果。     

晶体表面特性对PET探测器性能的影响

<正>电子发射断层成像(Positron Emission Tomography,PET)作为最灵敏和具有定量测量能力的功能分子影像技术,越来越广泛地应用于生物医学研究,如疾病的动物模型、新药物的研发和新治疗方法的评估等。提高探测器的性能是改进PET仪器性能的关键,PET探测器通常由分割的闪烁晶体阵列和光探测器组成,文中使用位置灵敏光电倍增管和不同晶体表面特性的硅酸钇镥((Lu,Y)2Si O5,LYSO)晶体阵列,对新型的双端读出三维PET探测器和传统的单端读出二维PET探测器的性能进行了测量。实验结果表明,对于双端读出PET探测器,两种晶体阵列提供相近的晶体分辨图和能量分辨率,但非抛光晶体阵列提供好的深度分辨率,双端读出PET探测器需要使用表面不抛光的晶体阵列;对单端读出PET探测器,抛光晶体阵列提供好的晶体分布图和能量分辨率,单端读出PET探测器需要使用表面抛光的晶体阵列。     

高分辨粉末衍射仪数据采集系统研制

介绍了中国先进研究堆(CARR)旁高分辨粉末衍射仪数据采集系统的整体设计和硬件组成,阐述了各单元电路的结构和设计。加载输入信号对电路进行了调试,测试了电路的各项性能,测试结果满足设计要求。从探测器、前置放大器、主放大器、甄别器、计数卡到计算机的整个系统,实现了对信号的获取、放大、滤波成形、甄别、定标计数和存储全过程,多达65路的数据采集系统已研制成功。     

Development of a compact DOI-TOF detector module for high-performance PET systems

To increase spatial resolution and signal-to-noise ratio in PET imaging,we present in this paper the design and performance evaluation of a PET detector module combining both depth-of-interaction(DOI) and time-offlight(TOF) capabilities.The detector module consists of a staggered dual-layer LYSO block with2 mm × 2 mm × 7 mm crystals.MR-compatible SiPM sensors(MicroFJ-30035-TSV,SensL) are assembled into an 8× 8 array.SiPM signals from both fast and slow outputs are read out by a 128-channel ASIC chip.To test its performance,a flood histogram is acquired with a ~(22)Na point source on top of the detector,and the energy resolution and the coincidence resolving time(CRT) value for each individual crystal are measured.The flood histogram shows excellent crystal separation in both layers.The average energy resolution at 511 keV is 14.0 and 12.7%at the bottom and top layers,respectively.The average CRT of a single crystal is 635 and 565 ps at the bottom and top layers,respectively.In conclusion,the compact DOI-TOF PET detector module is of excellent crystal identification capability,good energy resolution and reasonable time resolution and has promising application prospective in clinical TOF PET,PET/MRI,and brain PET systems.     

Bunch-by-bunch beam size measurement during injection at Shanghai Synchrotron Radiation Facility

Fast beam profile measurement is important in fast beam dynamic behavior investigations. A bunch-bybunch beam size measurement system, which is presently used to measure horizontal profile, has been developed at the Shanghai Synchrotron Radiation Facility(SSRF) and is capable of measuring bunches within a separation of 2 ns.The system is based on a direct-imaging optical system and high-speed photomultiplier array detector. A high-bandwidth linear signal amplifier and acquisition module have also been designed to process bunch-by-bunch multichannel signals from the detector. The software resampling technique and principal component analysis method were developed to obtain the synchronized data and enhance the signal-to-noise ratio. The fast injection of transients was successfully captured and analyzed. Moreover, the bunchby-bunch positions and sizes exhibited strong oscillation after the injection at the horizontal betatron oscillation frequency of the SSRF storage ring, and this demonstrated the bunch-by-bunch measurement capability of our system.     

Development of a fast electron bremsstrahlung diagnostic system based on LYSO and silicon photomultipliers during lower hybrid current drive for tokamak

A novel real time fast electron bremsstrahlung (FEB) diagnostic system based on the lutetium yttrium oxyorthosilicate scintillators (LYSO) and silicon photomultipliers (SiPM) has been developed for tokamak. The diagnostic system is dedicated to study the FEB emission in the hard x-ray (HXR) energy range between 10 and 200 keV during the lower hybrid current drive. The system consists of a detection module and three data acquisition and processing (DAP) boards. The detection module consists of annulus LYSO-SiPM detector array and a 12-channel preamplifier module. The DAP boards upload the data to the host computer for displaying and storing through PXI bus. The time and space resolutions of the system are 10 ms and 4cm, respectively. The experimental results can show the evolution over time and the spatial distribution of FEB. This paper presents the system performance and typical discharge results.     

基于APD阵列的PET探测器模块电子学

APD阵列γ光子探测器的诸多优点使多特别适用于PET成像技术，根据APD器件本身的特点以及PET系统对探测器模块信号读出的要求，在介绍APD实验模块前端电路的设计和性能测试以后，详细讨论了APD模块电子学的整体设计。