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.     

碲锌镉探测器对低能X射线的探测

介绍了碲锌镉探测器对低能X射线的探测,并在不同温度下测试了其性能变化,包括电子学噪声,能量分辨率和漏电流的变化.同时研制了低噪、性能稳定的厚膜电路用于单路信号的读出,对241Am的60keV能量峰的能量分辨率达到了4%.     

高分辨高纯锗低能光子探测器研制

用硼离子注入方法制备P~+电极,采用沟槽形结构,成功地研制出高分辨高纯锗低能光子探测器。4个有代表性的探测器能量分辨率分别为FWHM=183,178,165,162eV。探测器灵敏体积分别为φ16mm×12mm,φ13mm×10mm,φ13mm×9.7mm和φ13mm×9.5mm。此4个探测器的性能达到了国际先进水平。     

Applications of Detectors in Low Energy Nuclear Physics

This review paper discusses new applications of detectors in low energy nuclear physics and emphasizes semiconductor particle detectors where new developments have had an outstanding influence on the nuclear physics which can be done. The paper includes an account of: new limits of detector resolution; a new method for measurement of gamma ray lifetimes; gamma-gamma angular correlation studies with multiple scintillation detectors; kinematic energy shift correction with radial position sensitive detectors; an improved particle identification system with multiple detectors; and the application of germanium to measurements of long-range charged particles. The paper also discusses present state-of-the-art limitations and possibilities in areas of particular importance to nuclear physics.     

Calibration of Bubble Detectors With High Energy Heavy Ions

Calibrationsoffivetypesofbubbledetectors(T-12,T-14,T-24,T-34andT-15types)havebeencarriedoutwith400MeV/uXe,500MeV/uKr,600MeV/uFeand180MeV/uHe,respectivelyattheHIMACaccelerator(HeavyIonMedicalAcceleratorinChina).Bubbletracksformedinthedetectorshaveverydiffe…     

Low Temperature Characteristics of Ion Implanted Silicon Position Sensitive Detectors

The operation of ion implanted silicon position sensitive detectors at low temperatures will be described. The improved noise performance of the detector at these temperatures in both the energy and position modes will be analyzed and its implications on low energy applications will be discussed. A large part of the investigation was devoted to the study of boron implanted resistors and their noise properties both at room temperature and cryogenic temperatures.     

离子注入型与金硅面垒型半导体探测器温度特性比较

半导体探测器性能受温度影响较大,影响着辐射探测系统的稳定性和测量精度。本文设计了一个温度测试电路,通过温度测试实验分别得出了离子注入型和金硅面垒型半导体探测器的温度特性曲线。测试结果表明,离子注入型半导体探测器的温度特性明显优于金硅面垒型半导体探测器。本文的结果可为半导体探测器的使用、筛选提供参考。     

Multi-pinhole SPECT Imaging with Silicon Strip Detectors

Silicon double-sided strip detectors offer outstanding instrinsic spatial resolution with reasonable detection efficiency for iodine-125 emissions. This spatial resolution allows for multiple-pinhole imaging at low magnification, minimizing the problem of multiplexing. We have conducted imaging studies using a prototype system that utilizes a detector of 300-micrometer thickness and 50-micrometer strip pitch together with a 23-pinhole collimator. These studies include an investigation of the synthetic-collimator imaging approach, which combines multiple-pinhole projections acquired at multiple magnifications to obtain tomographic reconstructions from limited-angle data using the ML-EM algorithm. Sub-millimeter spatial resolution was obtained, demonstrating the basic validity of this approach.     

Transient Response of Surface Barrier Detectors as a Function of Fission Fragment Energy

The transient response of silicon surface barrier detectors to fission fragments of Cf252 was observed over a range of incident fragment energies from 13.6 to 90 MeV. From these observations the effect of the plasma formed by the incident particle on the charge collection time was determined. The time to disperse the plasma, tp, was calculated as a function of incident particle energy, Eo, and applied field, E. It was found that tp ? Eo1/m where 2 ? m ? 3 and tp ? E-1. A simple model gave reasonable agreement with the experiments and indicated that the plasma is dispersed by field-enhanced diffusion.     

厚灵敏层金硅面垒探测器

本文介绍了最大耗尽厚度达5mm,最大有效面积为80—153mm~2的厚灵敏层金硅面垒探测器研制工艺,主要用途和测试结果。     

外延硅dE／dX探测器的研制

本文介绍了厚度为５．２－６．０、１０－１３、１９μｍ，有效面积为２８－１５４ｍｍ＾２的外延硅ｄＥ／ｄＸ探测器的研制工艺，主要用途，测试结果（对９．８７ＭｅＶ α粒子的能损△Ｅ的分辨率为５６－１２８ｋｅＶ）和在核物理实验中的应用。     

平面工艺Si-PIN低能X射线探测器研制

叙述了用平面工艺技术制备Si-PIN低能X射线探测器的工艺方法.为了减小探测器的漏电流,采用了表面钝化和保护环技术.文章给出了厚度500μm,灵敏面积分别为5 mm2、10mm2的不同探测器在室温下漏电流测量结果以及5mm2的探测器在室温及温差电致冷条件下对55Fe5.9keV X射线的能谱响应测量结果.     

Low Energy Dosimetry With Photon Counting Pixel Detectors Such as Medipix

Hybrid semiconductor photon counting pixel detectors like the Medipix detector have several advantages for an use in X-ray dosimetry. The noiseless photon counting principle allows to monitor low photon energies down to 3.5 keV. Due to the small pixel size (55 mum in case of Medipix2) dosimetry at very high dose rates is possible still processing each photon individually. The large amount of pixels in combination with the possible thickness of the sensor layer enables dosimetry at very low dose rates. A method has been developed to determine personal dose equivalents from the number of counts in energy deposition intervals measured with a semiconductor photon counting pixel detector, despite the strong influence of charge sharing effects among pixels. We tested the method experimentally by reconstructing the air kerma free in air for different qualities of X-radiation in the energy range below 150 keV with an accuracy better than 4%. We show that the response of a dosimeter based on a hybrid photon counting pixel detector can fulfill the IEC type testing requirements. The statistical precision is high due to the thickness and the large area of the sensor layer. We estimate that a dosimeter based on the Medipix detector will be able to cope with dose rates of more than approximately 57 Sv/h for mathdot Hp (0.07) or 19 Sv/h for mathdot Hp(10) . We outline the advantages and perspectives of using this kind of detector in a dosimeter in comparison to standard active personal dosimeters.     

硅漂移探测器的制作工艺及特性研究

采用双面并行的平面工艺研制出了有源区面积5mm2的硅漂移探测器(SDD).这种双面并行的平面工艺使得SDD绝大部分正面和背面的pn结结构能够并行完成,极大地减少了工艺步骤,降低了器件制作的难度.对研制的SDD的漏电流、电势分布、光电子的漂移特性等进行了测量和分析,对233Pu a射线源的能谱进行了测量.对正常工作状态下出现的悬空阳极电位进行了分析和讨论.报道了利用阳极漏电流、光电子漂移特性、悬空阳极电位对SDD芯片进行中测和封装前快速筛选的方法.     

Design of Multi Anode Gas Ionization Chamber with Si_3N_4 Windows for Detection of Low Energy Heavy Ion

<正>In order to establish accelerator mass spectrometry technology of the detection of low energy heavy ions,gas ionization chambers with thin windows need to be developed.Mylar membranes are generally used for conventional gas ionization     

低能X射线工业CT探测器光电转换效率的研究

光电转换效率是低能工业CT探测器的重要性能参数。分析了几种常用闪烁晶体的发光效率、几何尺寸、发光波长等参数对光电转换效率的影响,并通过实验测试比较了不同厚度(闪烁体沿X射线方向的尺寸)的CsI(TI)和CdWO4闪烁体探测器的光电转换效率。证明在低能工业CT中,CsI(TI)比CdWO4更适合用作X射线探测器闪烁体材料,且闪烁体的厚度对光电转换效率的影响很大。这对优化工业CT系统探测器闪烁体的选型与尺寸设计具有一定的参考价值。     

Measurevent of the Transient Effects of a Gamtma-Flux on the Energy Resolution of Surface-Barrier Silicon Detectors

The energy resolutions of surface barrier n-type silicon detectors counting al pha-particles were measured under the disturbance of 1.25 MeV gamma-fluxes ranging from 2.3 x 107 to 3.8 x 108 photons cm-2 sec-1 and for detectors having different total thicknesses and resistivities. The results obtained confirm the existence of a zone about 100 micron wide and external to the depletion layer of partially depleted detectors which contributes to worsen the energy resolution of the gamma-irradiated detectors by diffusion rrocesses. It is also pointed out that the energy resolution of the detectors under gamma irradiation varies with the time constants of the amplifying circuit quite differently from what is obser ved in the absence of gamma irradiation.     

碳化硅热中子探测器的优化设计

采用MC法对用于热中子探测的碳化硅探测器开展设计。优化了中子转换层参数和半导体器件参数,研究表明采用~(10)B作为中子转换材料,其最优厚度为2μm,在系统甄别阈为300 keV时对应的探测效率理论值为3.29%。制备了碳化硅外延层厚度20μm,灵敏区面积5 mm×5 mm的碳化硅器件,在外加反向偏压达180V时,其漏电流仅20.8 nA。性能测试表明:该器件对4.7-6.0 MeV的α粒子具有极好的能量线性,其线性度达0.999 97。对5.49 MeV的α粒子的能量分辨率为1.03%,对应半高宽57.3keV,与SiC高分辨α探测器分辨率相当。