新型晶体阵列探测器在MicroPET中的应用

PET因为采用了符合探测的原理,所以可得到高分辨率的图像。将这项技术应用于小动物的各项研究之中,就开发出了MicroPET系统。MicroPET在生物学、医学和药学等方面具有重大的意义。简述了MicroPET的研究意义和发展历史,并以加州大学洛杉矶分校研制的MicroPET样机为例,介绍了MicroPET及其新型晶体阵列探测器的结构、原理和发展方向。     

大面积高灵敏度编码相机探测器的设计与性能测试

编码孔径相机是一种定位放射性物质的设备,对丢失放射性物质的寻找以及监测具有重要的意义。为了满足编码孔径相机对核突发事故的污染区进行实时定位,并获得污染面积和污染程度等信息,采用大面积CsI(Tl)晶体阵列与光电倍增管(PhotoMultiplier Tube,PMT)阵列耦合的方式构建高灵敏度编码相机的探测器,以此提高探测效率并减少探测时间。该探测器由121根CsI(Tl)晶体构成11×11的阵列,每根晶体的尺寸为15 mm×15 mm×15 mm,通过光导与3×3的光电倍增管阵列耦合为一个探测器模块;由4个探测器模块组成2×2的阵列作为探头部件,采用自主设计的放大滤波成型以及单端转差分电路实现探测器信号的读出处理。通过测试发现,该探测器模块在662 keV的γ射线激发下,能很好地实现各个晶体条的位置分辨,且其平均能量分辨率为9.4%。测试结果表明:该探测器在位置分辨、能量分辨率、峰位一致性以及探测效率一致性等性能方面均能够满足高灵敏度编码相机成像的设计要求。     

Test system of the front-end readout for an application-specific integrated circuit for the water Cherenkov detector array at the large high-altitude air shower observatory

The water Cherenkov detector array (WCDA) is an important part of the large high-altitude air shower observatory (LHAASO),which is in a research and development phase.The central scientific goal of LHAASO is to explore the origin of high-energy cosmic rays of the universe and to push forward the frontier of new physics.To simplify the WCDA's readout electronics,a prototype of a front-end readout for an application-specific integrated circuit (ASIC) is designed based on the timeover-threshold method to achieve charge-to-time conversion.High-precision time measurement and charge measurement are necessary over a full dynamic range [1-4000 photoelectrons (P.E.)].To evaluate the performance of this ASIC,a test system is designed that includes the front-end ASIC test module,digitization module,and test software.The first module needs to be customized for different ASIC versions,whereas the digitization module and test software are tested for general-purpose use.In the digitization module,a field programmable gate array-based time-todigital converter is designed with a bin size of 333 ps,which also integrates an inter-integrated circuit to configure the ASIC test module,and a universal serial bus interface is designed to transfer data to the remote computer.Test results indicate that the time resolution is better than 0.5 ns,and the charge resolution is better than 30％root mean square (RMS) at 1 P.E.and 3％ RMS at 4000 P.E.,which are beyond the application requirements.     

用于硅多条阵列探测器的48路前置电荷灵敏放大器的研制

介绍了一套用于硅多条阵列探测器中的高密度多通道电荷灵敏放大器的研制和阵列探测器电子学的发展现状和工作原理,提出了设计原则和设计思路,特别介绍了一个新开发的用于硅多条探测器中的48路电荷灵敏前置放大器的设计和实际测量结果.它具有低成本、高密度的特点,好于1%的能量分辨和良好的长期稳定性.     

A digitalizing board for the prototype array of LHAASO WCDA

In this paper,a digitalizing board for readout of PMT signals in the prototype array of WCDA(water Cerenkov detector array)for LHAASO(Large high altitude air shower observatory)is designed.The prototype array is composed of 9 PMTs,including the pulse time and charge measurement from the PMTs,and clock generation and trigger decision.In the digitalizing board,FPGA reconfiguration and data readout via VME bus are implemented.Test results show that the performances meet well with the requirements of readout electronics.It has been installed in Yangbajing and tests with the prototype array and DAQ is ongoing.     

CSR系统终端中子墙光电倍增管时间型分压系统的应用研究

在兰州重离子加速器冷却储存环将要建设的外靶实验终端上，中子墙探测装置是用来开展放射性束物理以及利用放射性束开展非对称核物质性质研究的一个重要的实验设备。本文对应用于该实验装置上的光电倍增管分压系统进行了研究，给出了适合时间性能探测的时间型分压器设计参数以及测试结果。     

数字辐射成像系统阵列探测器成像变形分析

在数字辐射系统(DR)如60Co集装箱检测系统(TC-SCAN系统),采用圆弧形和直线(折线)形两种形式的线探测器阵列,分析了两种探测器阵的成像变形,设计了削减这种变形的算法并在TC-SCAN集装箱检测系统中取得较好的应用.     

硅多条阵列探测器多路电荷灵敏前置放大器研制

本文简要介绍了应用于阵列探测器特别是硅多条阵列探测器的高密度多路前置放大器和前端电子学的发展现状、工作原理、设计要求和设计思路.同时,介绍了一套新开发的用于硅多条探测器中的48路电荷灵敏前置放大器的电路设计和实际测量结果,它具有低成本、高密度、好于1%的能量分辨和良好的长期稳定性.     

3.0MeV高频高压电子加速器计算机监控系统的研制

描述了基于PLC的高频高压电子加速器的计算机监控系统。在满足加速器正常操作的基础上,增加了能量反馈控制回路,提高了输出能量的稳定度(1％);保证了扫描电流的大小随输出能量变化的自动跟踪调节：在故障诊断方面也提供了有效的手段帮助排除故障或分析故障原因。     

Development of a compact high resolution gamma-ray detector for E-CT applications

A compact gamma-ray detector with good spatial resolution for emission computed tomography (E-CT) applications has been developed. The detector is composed of NaI(Tl) scintillation pixels array and Hamamastu R2486-05 PSPMT. Having a pixel size of 2 mm × 2 mm and an overall dimension of 48.2 mm × 48.2mm × 5 mm, it has 484 pixels in a 22×22 matrix. An average spatial resolution of 2.5mm (FWHM) was achieved. The slope of position linearity is constant within 10% in a range of 40mm. After corrections, the average value of differential non-linearity and absolute non-linearity were 0.16mm and 0.535mm respectively, and a 17% at FWHM of total energy resolution for 241Am was obtained.     

上海电子束离子阱装置真空控制系统

本文介绍了基于RS485总线结构和LabVIEW图形化软件环境的上海电子束离子阱(EBIT)装置真空控制系统,详细分析了对真空设备远程操作和数据采集以及真空联锁的实现方法。测试结果表明该系统达到了设计指标,满足了实验使用要求,目前已成功地应用在上海EBIT装置中。     

用于CBM-TOF超级模块探测器质量控制的分布式数据读出方法

高压缩重子物质(Compressed Baryonic Matter,CBM)实验装置飞行时间谱仪利用由多气隙电阻板室(Multi-gap Resistive Plate Chamber,MRPC)探测器构建的超级模块实现高密度、高精度的粒子飞行时间测量,该超级模块可支持高达320通道的高精度时间测量能力,数据率高达6 Gbit·s~(-1)。为实现超级模块探测器的性能评估,提出一种基于千兆以太网的分布式数据读出方法,利用片上系统技术实现读出节点的千兆网络传输能力。测试结果表明,针对单条数据传输路径,原型读出模块在全链路情况下,能实现约467 Mbit·s-1的综合数据传输速率。读出方案中事例组装、命令发送、状态显示等功能均运行正常。