特殊结构的金硅面垒探测器的双峰现象及反偏压现象

由于工作需要,从对探测器耗尽深度和工作电场的要求出发,我们使用了结构如图1的金硅面垒型半导体探测器。对这种探测器进行检验时,发现了与一般硅面垒探测器(非全耗尽的)不同的反常现象,即双峰现象和反偏压效应。一、特殊结构的金硅面垒型探测器     

金硅面垒型半导体探测器在氢气环境下失效现象的实验研究

当金硅面垒型半导体探测器在氢气环境下使用的时候,α能峰会向低能方向飘移,直至淹没在电子学噪声中。本文通过实验介绍了金硅面垒探测器在氢气环境下的这种失效现象,总结了失效现象的规律;提出了金硅面垒探测器在氢气环境受影响的机理,并进行了实验验证。     

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。     

^6LiF夹心谱仪探头用金硅面垒探测器性能测定

金硅面垒探测器是6LiF夹心谱仪探头的关键组成部分,其参数直接影响整个夹心谱仪的性能.通过实验测定了各金硅面垒探测器在不同偏压下的漏电电流、空气对α粒子的影响、金硅面垒的死层厚度、偏压对峰位和分辨率的影响,以及在180V偏压下各金硅面垒探测器的最大能量峰位.根据测量结果,选出了两组性能基本相同的金硅面垒探测器,将其组装成性能优良的6LiF夹心谱仪效应探头和本底探头.     

一台用于重核素测量的能量-飞行时间探测系统

研制了一台用于重核素测量的能量-飞行时间探测系统.探测系统由飞行时间探测器和金硅面垒型能量探测器组成,金硅面垒型探测器兼做飞行时间探测器的停止探测器.用该探测系统在中国原子能科学研究院串列加速器质谱装置上对182Hf9+离子的能量-飞行时间双维谱进行了测量.该探测系统对77.4 MeV182Hf9+离子的能量分辨率为3.8％,飞行时间分辨为0.8ns.     

透射电离室作为低能质子束流监测器的研究与应用

为有效监测低能质子的束流强度,研制了一种透射型电离室,用于HI-13串列加速器上低能质子束流的监测。研究了它的基本计量学性能,结果表明,各项性能均满足工作级电离室的要求。与传统的侧向束流监测用金硅面垒探测器测量结果相比,基于同向测量的透射电离室作为监测探测器明显优于金硅面垒探测器,提高了测量结果的准确度。     

一种简易实用的三管电荷灵敏放大器

设计了一种简易实用的3管电荷灵敏放大器,其使用器件少,调试简单,具有较好的信噪比,适用于离子注入式半导体探测器、金硅面垒半导体探测器的前置放大。     

半导体探测器的测试和应用

本工作主要是通过对大量的金硅面垒型和锂漂移型硅半导体核辐射探测器在空气中、真空中和冷却情况下的测试,了解影响能量分辨率、时间分辨率和使用寿命的因素,掌握探测器的最佳使用条件,从而应用这种探测器进行核反应带电粒子能谱、核衰变能谱及甄别粒子的测量,并取得了一些较好的结果。     

金-硅面垒型探测器

一、引言近年来,我国在半导体硅(锗)探测器的制作和应用方面越来越普遍。这种器件之所以获得迅速进展,主要是用起来很方便。并且,在性能上与早期在核物理实验中所一直延用的探测器件相比,有其独到之处。如在一定能量范围内分辨率高,脉冲上升时间短和线性非常好,等等。目前国际上对这种器件的研究也很时兴。我们实验室主要制备硅面垒型探测器(磷扩散型器件过去也做过)。N型硅材料是由本所自己制备的。一般材料的电阻率在几百到几千欧姆·厘米之间,位错浓度约为10V厘米~2,载流子寿命约在几十到几百微秒之间,器件的面积一般约为40—80毫米~2,最大的有效面积可达200—300毫米~2。用这种器件测得的分辨率(对于Po~(210)α源)最好的约为0.47—0.57%。空间电荷层厚度可达600微米以上。     

锂漂移金硅面垒型探测器

本文详细地描述了锂漂移金硅面垒型探测器的制造工艺。这种探测器同时兼备了锂漂移型和面垒型探测器的优点。文中给出了探测器的主要性能,并对实验中的一些现象进行了讨论。探测器有效面积的直径为2—20毫米,灵敏区宽度高达4.5毫米。在窒温下,对于5.3兆电子伏的α粒子的能量分辨率为1—2%,对于Cs~(137)转换电子的能量分辨率为3.7%。探测器结构牢固,能应用于真空条伴。     

Comparative Timing Performance of Large Volume Ge(Li) and HPGE Coaxial Detectors

The timing performance of several large (8% to 12% relative efficiency) Ge(Li) and HpGe coaxial detectors has been measured and compared. The Ge(Li) detectors are capable of timing resolution which is generally 10% to 30% better than that of the HpGe devices. This resolution capability can be attributed to the higher bias voltages which can be applied to the Ge(Li) detectors. However, in some applications that involve a wide dynamic range of energies, the HpGe devices can provide better timing resolution than their Ge(Li) counterparts. Advancements in the state of the art are expected to result in HpGe detectors that can provide timing performance equivalent to the performance of the best Ge(Li) devices.     

基于多种探测算法结果分级融合的PET探测器晶体查找表建立算法

高分辨率是现代正电子发射型断层显像仪(Positron Emission Tomography,PET)设备最重要的技术指标之一,高分辨率PET探测器通常由海量闪烁晶体组成,这使得探测器校准时,晶体查找表建立的工作量大幅增加,从而对相关自动化算法的鲁棒性提出了更高的要求。目前,晶体阵列的矫正主要依赖固定放射源对探测器晶体阵列成像得到的光子二维位置直方图。高分辨率PET探测器的晶体阵列中晶体个数增多,尺寸变小,导致二维位置直方图信噪比下降,且非线性形变更加复杂,使已有的晶体查找表建立算法都无法得到理想的自动化效率。在测试了多种前沿的晶体查找表建立算法后发现,某些算法的结果之间有很强的互补性,可以通过将多种算法结果相融合的方法得到优于单一探测算法的结果。因此提出了一种基于多种探测算法结果分级融合的晶体查找表建立算法,在实现过程中选取了三种互补性较强的晶体探测方法,分级融合其结果,大幅度降低了二维位置直方图上晶体分割的出错概率,获得了鲁棒的结果。     

Modified Reconstruction of Neutron Spectrum Emitted in Dense Plasma Focus Devices by MCNP Code and Monte-Carlo Method

In this study we present Monte Carlo method for obtaining the time-resolved energy spectra of neutrons emitted by D-D reaction in plasma focus devices. Angular positions of detectors obtained to maximum reconstruction of neutron spectrum. The detectors were arranged over a range of 0–22.5 m from the source and also at 0°, 30°, 60°, and 90° with respect to the central axis. The results show that an arrangement with five detectors placed at 0, 2, 7.5, 15 and 22.5 m around the central electrode of plasma focus as an anisotropic neutron source is required. As it shown in reconstructed spectrum, the distance between the neutron source and detectors is reduced and also the final reconstructed signal obtained with a very fine accuracy.     

Radiation Detectors in High Energy Physics

Spark chambers, scintillation and Cerenkov detectors are used extensively in high energy physics experiments. The potential usefulness of semiconductor detectors is being investigated. There is a need for detectors which will identify very high energy particles. The various types of spark chambers are briefly reviewed, including narrow gap, wide gap and filmless chambers. Applications of scintillation detectors are discussed, together with remarks on light pipes, localization of particles by time-of-flight, use of multiparameter pulse height analysis, hodoscopes and on-line computers. The use of Cerenkov counters is summarized. Several new types of detectors are considered which may be suitable for identification of particles of very high energy, hundreds of BeV, including transition radiation detectors and semiconductor devices.     

Field Funneling and Range Straggling in Partially Depleted Silicon Surface-Barrier Detectors

The effects of field funneling and range straggling have been quantitatively observed in the measurement of charge collected from alpha-particle tracks in silicon surface-barrier charged-particle detectors. The method described may be used for the straight-forward measurement of charge collection from heavy ions in these and other semiconductor devices.     

Some Studies on the Time Resolved Energy Spectrum Reconstruction for Pulsed Neutron Source

The purpose of this article is to present some new numerical results concerning the time resolved energy spectrum reconstruction of a short pulsed neutron source, like one created in plasma focus devices. An MCNP code is used to simulate a time dependent neutron source, plastic scintillator detectors, and their recorded signals. A Monte Carlo program reconstructs spectrum using the signals produced by MCNP code. By the numerical computations we determined the optimum number of four detectors which are needed to be placed at 0, 10, 18 and 30 m from the source, respectively. A time resolution about 12 ns and an energy resolution of 40 keV are obtained. Neutron scattering in the air is considered, and it is found that the intensity of spectrum is increased by 6%.     

Wafer-Bonded Silicon Gamma-Ray Detectors

A wafer-bonded silicon power transistor has been shown to function as an x-ray detector. The device consists of two thin device wafers bonded onto either side of a 2 mm-thick high-resistivity silicon wafer. The hydrophobic bonding process was performed at 400deg C. This low temperature wafer bonding technique should enable the development of large-area, position-sensitive detectors, using thick, high-resistivity intrinsic silicon bonded to thin readout wafers fabricated using conventional CMOS technology. These devices should enable fabrication of thicker intrinsic silicon detectors than currently available. Thick, position-sensitive detectors based on double-sided strip detectors and pixellated detectors are possible. To demonstrate this, a 1 mm thick gamma-ray detector was created from two 0.5 mm thick wafers that were patterned with gamma-ray strip detectors. The energy resolution of the detector is 8.9 keV FWHM for 60 keV gamma rays at room temperature with a leakage of 0.9 nA while operating at 700 V and fully depleted. Improvements in the technique should allow for thicker detectors with better energy resolution.     

Calculation of pixel detector capacitances through threedimensional numerical solution of the Laplace equation

A method for the solution of the three dimensional Laplace equation is presented. The method applies to planar geometry cases, such as pixel detector devices, characterized by mixed boundary conditions. Through this algorithm the capacitances associated with pixel detectors are calculated. These capacitances, which are the pixel to substrate and the interpixel capacitances, are of great importance in the design of a pixel detector since they influence the noise and the cross talk effects between pixels. Capacitances for various pixel and interpixel dimensions are presented along with an analytical approximation for the calculation of the total pixel capacitance