一种用于空间粒子成像谱仪的计数器阵列

为满足目前磁层物理研究的需要,先进的粒子探测器需获得粒子能谱的三维分布。设计一种可用于多方向空间带电粒子的能谱测量的计数器阵列。该计数器阵列用1个4K×8位的双口RAM实现了拥有2048个通道的16位计数器阵列。目前,已完成原型设计,并利用精密脉冲信号源和放射源进行了性能测试。测试结果表明,该计数器阵列性能良好,具有尺寸小、功耗低、灵活性高等特点。     

查找表方式的粒子辐射脉高分析器

介绍了一个用于空间高能粒子探测的多道脉高分析器电路的设计。该分析器通过模数转换器把输入信号数字化,再利用查找表来完成能段甄别工作。能档计数和数据传输由80C31单片机控制。该电路能精确地对辐射脉冲进行幅度甄别,并给出入射粒子的能档,而且系统可靠性高,易于校准和标定。     

A New Filter Concept Yielding Improved Resolution and Throughput in Radiation Detection Systems

We introduce a new filtering method capable of increasing measurement resolution and processed data throughput through a nonstandard baseline restoration technique. An overall optimization of the signal-to-noise ratio and of the processing efficiency is performed and new filters are obtained. The hardware implementation exploits the resources of a FPGA and is not significantly resource-hungrier than standard setups. The experiments confirm theoretical expectations. The obtained resolution is 1.8 keV on the 1.173 MeV peak: This result is an improvement with respect to the one achievable with the standard optimum filter in the same conditions by about a 10% factor; the data rate is improved too.     

环境辐射监测数字伽玛谱仪设计

本文介绍了一种环境辐射监测数字伽玛谱仪设计方案。本设计采用Na I(Tl)探测器对伽玛射线进行探测,由FPGA控制可编程增益放大器对核脉冲信号进行调节,以适合后续模数转换输入要求。由FPGA控制高速模数转换器AD9235对核脉冲信号进行模数转换,然后采用海明窗低通FIR数字滤波器对数字核脉冲信号进行滤波,滤除高频噪声。本设计采用TMS320C6713对数字核脉冲信号进行梯形成形,改善弹道亏损和脉冲堆积,最后对其进行幅值判断形成能谱。谱仪经刻度后,不仅可以获得现场辐射计数总量还可以获取现场能谱对核素进行初步判别,这对于工业环境辐射监测非常有意义。本设计具有体积小、设计灵活、可扩展性好等特点,非常适合现场环境辐射监测。     

Fault Tolerant Memories for Single Particle Radiation Effects

Fault tolerant memory mechanizations are presented in this paper which combine standard Error Detection and Correction (EDAC) techniques with unique memory electrical/spacial organizations and computer protocols which account for single particle radiation effects and significantly reduce their impact on the memory system. The mechanizations also enhance reliability and increase survivability to macroscopic radiation effects including total dose failure and dose rate upset. Standard EDAC mechanizations allow the memory designer to reduce susceptibility to single particle soft upsets at the system level by orders of magnitude. The memory organization and computer protocols presented herein extend this susceptibility reduction to latchup and multiple soft or hard errors in a common word. The mechanizations are compatible with implementation on auxiliary LSI chip sets or partially in VHSIC RAM device structures themselves. They are also compatible with fault tolerant computer mechanizations which account for failure or upset of non RAM device logic circuitry (Processor and Memory).     

Silicon Detectors for Low Energy Particle Detection

Silicon detectors with very thin entrance contacts have been fabricated for use in the IMPACT SupraThermal Electron (STE) instrument on the STEREO mission and for the Solid State Telescopes on the THEMIS mission. The silicon diode detectors were fabricated using a 200 Aring thick phosphorous doped polysilicon layer that formed the thin entrance window. A 200 Aring thick aluminum layer was deposited on top of the polysilicon in order to reduce their response to stray light. Energy loss in the entrance contact was about 350 eV for electrons and about 2.3 keV for protons. The highest detector yield was obtained using a process in which the thick polysilicon gettering layer was removed by chemical etching rather than chemical mechanical polishing.     

The Plastic Ball ? a Multi-Detector, Large Solid Angle Spectrometer with Charged Particle Identification for the Bevalac

For the study of central relativistic nuclear heavy ion collisions, which are characterized by the emission of a large number of particles, one needs a detector which covers a large solid angle ? 4? if possible ? and which is capable of identifying charged particles. The high multiplicity requires a large number of detectors, and the need for charged-particle identification requires a measurement of the energy loss, and the total energy for each particle detected. The spectrometer consists of 815 detector modules, which cover 94% of 4?. The geometry of these modules has been taken from the Stanford crystal ball detector for ?-rays ? with minor modifications. This geometry is suited for the high multiplicities of particles emitted in relativistic heavy ion collisions. The dimension of the individual elements have been chosen to stop 240 MeV protons. Above this energy reaction losses start to dominate, so that the light output of a scintillator would no longer be a true indication of the energy. Out of 100 charged particles, 94 will hit the Plastic Ball, 87 will fire a detector element, and 80 will be identified uniquely. For the individual detector modules we have used the "Phoswich" idea, by gluing a 4 mm thick CaF2 scintillator to a 35 cm thick plastic scintillator (NE114) with the shape of a truncated pyramid, which is viewed by one photomultiplier tube (PM2202B).     

A Microchannel Plate Based Detector for a Heavy Ion Beam Spectrometer

The design parameters and operating characteristics of the detector used in the Brutus and Fannie heavy ion beam spectrometers at the SuperHILAC facility are described. The detector utilizes a 25 mm diameter microchannel plate array to obtain gains of 102 to 108 with a linear dynamic range of 103. It has had over three years of almost maintenance-free service, detecting ion beams from carbon to xenon with energies between 1.2 and 8.5 MeV per nucleon.     

多功能宽量程辐射探测系统研制

论文介绍一种多功能宽量程辐射探测系统的研制。该系统选用GM管与Na I(Tl)γ谱仪,通过嵌入式设计、实验标定、能谱剂量率转换、软件开发等工作实现系统的宽剂量率量程、双参数探测、自动温漂修正、无线数据传输和探测轨迹标定等功能。该系统可搭载无人旋翼机等设备进行远程探测,具有一定的辐射环境分析能力。实验表明该系统在0.01μGy/h~100 m Gy/h的辐射场内剂量率测量误差小于8%,上位机能在3 km距离获取作业路径、γ能谱和剂量率等探测信息。     

多功能宽量程辐射探测系统研制

论文介绍一种多功能宽量程辐射探测系统的研制。该系统选用GM管与Na I(Tl)γ谱仪,通过嵌入式设计、实验标定、能谱剂量率转换、软件开发等工作实现系统的宽剂量率量程、双参数探测、自动温漂修正、无线数据传输和探测轨迹标定等功能。该系统可搭载无人旋翼机等设备进行远程探测,具有一定的辐射环境分析能力。实验表明该系统在0.01μGy/h~100 m Gy/h的辐射场内剂量率测量误差小于8%,上位机能在3 km距离获取作业路径、γ能谱和剂量率等探测信息。     

Z-箍缩X射线辐射功率闪烁探测系统

研制的Z-箍缩X射线辐射功率探测系统，利用闪烁体与X射线作用产生的荧光，在X射线入射45°方向进行探测。系统具有平坦能量响应、大动态范围和抗干扰能力强的特点。在Z-箍缩“强光1号”装置上，对X射线辐射功率进行测量，获得了W丝阵负载最大X射线辐射产额为36-58kJ，辐射功率为0-84TW。     

光电二极管在辐射探测系统中的线性应用研究

针对光电二极管电压型放大器在辐射探测系统引起的非线性响应,分析并验证了光电二极管电压放大器在稳定辐射探测中,主要因响应度受到调制而出现响应非线性;在脉冲辐射探测中,影响系统线性度的是电压放大器中的带宽调制现象;提出了将带有电压跟随器的互阻放大器作为各种辐射探测的解决方案;阐明了从线性度考虑出发,用光电二极管互阻放大器代替电压式放大器的合理性。     

Performance of Fuel Failure Detection System for Coated Particle Fuels

An experimental system was developed for a study of fuel failure detection (FFD) method for coated particle fuels (CPF's) of a high-temperature gas-cooled reactor. Various performances of the FFD-system were examined using a CPF-irradiation rig in the Japan Material Testing Reactor. By experiments, it was made sure that the counting rates of fission products (FP's), released from the CPF's, change with the reactor-power and the fuel-temperature remarkably even during the normal reactor operation. Also, an ability of the selective detection of only short-life FP-nuclides was studied in relation to the travelling time of the sampling gas. The results showed that the contributions of the short-life FP-nuclides such as Kr-89 and Kr-90 are more than 80 percent to the total FP-counting rate at the shortest travelling time of 120 sec. It is concluded that the selective detection of only the short-life FP-nuclides can be realized by controlling the travelling time properly.     

用于化合物半导体探测器的小型电荷灵敏前置放大器

本文介绍了以运算放大器为主要器件的用于化合物半导体探测器低功耗、低噪声的小型化电荷灵敏前置放大器。     

A High-Efficiency X-Ray Crystal Spectrometer for X-Ray Thomson Scattering

Highly oriented pyrolitic graphite (HOPG) has high X-ray diffraction efficiency due to its unique mosaic crystal structure, and thus is very suitable for its application to X-ray Thomson scattering measurement of solid-density plasmas. In this article, by using the K-shell X-ray source from laser-produced Ti plasma, the properties of the HOPG spectrometer are characterized and compared with those of the flat Pentaerythritol (PET) spectrometer. The results show that the diffraction efficiency of the HOPG spectrometer under focusing condition is an order higher than that of the PET spectrometer, while the spectral resolution of the HOPG is about 320, high enough to be used in the measurement of X-ray Thomson scattering spectra.     

BaF2探测器测量α粒子的时间分辨随温度变化研究

本工作对用于测量α粒子的BaF2探测器的时间分辨随温度变化情况进行了实验研究.实验选用退激Y射线能量较高的237Npα源,利用α粒子与退激Y射线的时间关联性得到时间谱,在不改变任何条件的情况下对BaF:晶体加热,加热到设定温度后保持恒温,在BaF:晶体达到热平衡后开始测量时间谱,由该时间谱上读出的半高宽与标准偏差的线性关系得出α粒子的时间分辨随温度变化的情况.测量结果显示,时间分辨随温度变化在目前实验条件下较为明显,这为未来快时间分辨α粒子探测器的选择和优化使用提供了依据.     

激光共振电离质谱用钚源的制备及探测效率测定

为提高激光共振电离质谱（LRIMS）中钚的原子化效率,设计制备了金属包覆钚源,以期提高LRIMS测量痕量钚的灵敏度。本工作设计加工了适用于痕量钚制源的电沉积装置,研究了水相中痕量钚的电沉积条件,实现了痕量钚的定量电沉积;对比研究了金属铂和钛的电镀条件及性能,确定了以钛为包覆层的真空蒸镀条件,实现了镀层厚度为1 μm、金属钛包覆的高效钚源中钚的总沉积率达95%。研究表明,制备的高效钚源经过LRIMS测试,仪器对钚样品的总探测效率为2.5×10^-4,原子化效率提高至7.7%,较直接滴加源提高3个数量级,为LRIMS法高灵敏测量环境中痕量钚奠定了基础。     

A Ring Image Cerenkov Detector for the CERN Omega Spectrometer

A development program has been undertaken to produce a large ring image Cerenkov detector (RICH) for use at the CERN Omega Spectrometer. A prototype Cerenkov counter has been constructed and successfully operated in a high energy particle beam, Cerenkov rings having been observed in an experimental time projection chamber (TPC) using the photoionising agents Triethylamine (TEA) and Tetrakis (dimethylamine) ethylene (TMAE). Systematic measurements have been made of the optical properties of window materials and reflecting surfaces in the vacuum ultraviolet region. Results of these tests are presented, and the design of the large detector based on these experiences together with Monte Carlo simulations of the events expected in the WA69 experiment, is discussed.     

Hydrogenated Amorphous Silicon Sensor Deposited on Integrated Circuit for Radiation Detection

Radiation detectors based on the deposition of a 10 to 30 mum thick hydrogenated amorphous silicon (a-Si:H) sensor directly on top of integrated circuits have been developed. The performance of this detector technology has been assessed for the first time in the context of particle detectors. Three different circuits were designed in a quarter micron CMOS technology for these studies. The so-called TFA (Thin-Film on ASIC) detectors obtained after deposition of a-Si:H sensors on the developed circuits are presented. High internal electric fields (10⁴ to 10⁵ V/cm) can be built in the a-Si:H sensor and overcome the low mobility of electrons and holes in this amorphous material. However, the deposited sensor's leakage current at such fields turns out to be an important parameter which limits the performance of a TFA detector. Its detailed study is presented as well as the detector's pixel segmentation. Signal induction by generated free carrier motion in the a-Si:H sensor has been characterized using a 660 nm pulsed laser. Results obtained with a TFA detector based on an ASIC integrating 5 ns peaking time pre-amplifiers are presented. Direct detection of 10 to 50 keV electrons and 5.9 keV X-rays with the detectors are then shown to understand the potential and the limitations of this technology for radiation detection.