有限元模拟对CdZnTe共面栅探测器的优化设计

利用有限元分析软件ANSYS，通过变化栅宽、沟宽及栅极位置等因素，模拟了共面栅探测器在不同的电极设计时的电势分布，并讨论了电极分布不对称时所产生的边缘对感应信号的影响，显示了具有优化设计的共面栅电极，可以进一步提高探测器的能量分辩率。     

用于微光摄像的高灵敏度电子轰击电荷耦器件

文章综述微光成像的电子轰击电荷耦合器件（EBCCD）的进展。EBCCD是将像管的荧光屏以对电子灵敏的背照明、减薄CCD代替,将电子图像直接转变为视频信号,其在所有光照等级下,特别是在极低微光下的调制传递函数（MTF）、分辨力、信噪比、余辉等均优于像增强器耦合CCD（ICCD）。文中较为详细地叙述了倒像式EBCCD设计与减薄工艺,给出各种类型倒像式EBCCD像管的技术参数,分析和比较了近贴式与倒像式EBCCD与ICCD的性能,指出了EBCCD在军用夜视技术与民用技术未来发展中的地位与重要性。     

测量电子电量的又一种可行方法

根据固体物理的基本理论，通过测量PN结的正向伏安特性，采用非线性回归方法计算了电子电荷量，该值与公认值的误差仅为1．19％。该项研究结果拓宽了测量电子电荷量的渠道，有一定的参考意义和应用价值。     

CdZnTe核辐射探测器表面物理和化学钝化研究

表面漏电流引起的噪声会限制CAznTe(CZT)探测器的性能。尤其对于共面栅探测器,漏电噪声的大小与器件的电极设计和表面处理工艺密切相关。本文比较了探测器表面的物理和化学钝化工艺：采用H2O2溶液和KOH—KCl溶液对CZT样品进行湿化学钝化处理,采用RFPCVD法在CZT样品表面沉积类金刚石薄膜(DLC)进行物理干法钝化。借助俄歇电子能谱(AES)和显微拉曼光谱以及ZC36微电流测试仪等手段研究了CZT表面组成与器件电学性能之间的关系。AES结果表明KOH—KCl溶液钝化可以改善CZT样品表面的化学组分比,H2O2溶液钝化可以将表面富Te层转化为高阻氧化层,钝化前后的I-V特性曲线表明两种化学钝化方法均可以有效地减小器件表面漏电流,达到满意的钝化效果。CZT样品表面物理钝化通过在样品表面沉积DLC薄膜加以实现,显微拉曼光谱表明CZT表面钝化层是高sp^3含量的DLC薄膜,AES深度剖析表明DLC薄膜可以有效阻止CZT内部元素的外扩散,并且DLC薄膜内部C元素向CZT内部的扩散也是比较低的。DLC薄膜钝化后的CZT共面栅探测器表面栅距25μm的栅间电阻可以达到12GΩ,有效地降低了器件的表面漏电流。     

Charge sharing in common-grid pixelated CdZnTe detectors

The charge sharing effect in pixelated CdZnTe (CZT) detectors with a common anode steering grid has been studied. The impact on energy resolution of weighting potential cross-talk and ballistic deficit due to cathode signal shaping has been investigated. A detailed system modeling package considering charge induction, electronic noise, pulse shaping, and ASIC triggering procedures has been developed to study the characteristics of common-grid CZT detectors coupled to the VAS_UM/TAT4 ASIC. Besides an actual common-grid CZT detector coupled to VAS_UM/TAT4 ASIC, a prototype digital read-out system has been developed to better understand the nature of the charge sharing effect.     

Surface trapping and detector degradation in Ge bolometers for the EDELWEISS Dark Matter search: experiment and simulation

Surface charging effects are investigated in a germanium ionization-heat detector operated at cryogenic temperatures. Under properly defined biasing conditions, carriers of one type only (either electrons or holes) are driven in a controlled manner into the free surfaces of the detector where they become trapped. Computer simulations allow to determine the surface densities of trapped carriers, and to reconstruct the scatter plot of γ-events in the degraded state. They allow one in particular to define several event populations with respect to detector degradation, attributed to different areas of energy deposition.     

Design of a new vacuum Compton gamma ray detector with clad metal electron converter plate

A newly designed vacuum Compton gamma-ray detector with Ta-Al clad-metal electron converter plate is described. The detecting efficiency for 1.25MeV gamma-ray is 7.85×10-3 electron/, which is 2.5 times higher than that with Fe converter plate. The designed detector has the merits of well processed and static vacuum keeping and can be used for intense pulsed gamma ray detecting.     

复合金属发射极真空康普顿探测器结构设计

采用Ta—Al复合金属电子转换靶设计了一种厚窗真空型康普顿探测器,其对1．25MeV1射线的探测效率达到7．85×10^-3e／γ,比Fe发射极探测器的探测效率高出约2．5倍。探测器具有良好的封装加工和静态真空保持特性,可用于强流脉冲γ射线测量场合。     

Studies of electron trapping in GaN doped with carbon

Irradiation by the beam of the scanning electron microscope is shown to induce a systematic decay of the cathodoluminescence intensity in gallium nitride semiconductor doped with carbon. This decay is accompanied by increased electronic carrier diffusion length, indicating that electron irradiation results in the increase of carrier lifetime. Temperature-dependent cathodoluminescence measurements yielded activation energy for irradiation-induced effect of 210 meV. This observation is consistent with trapping of non-equilibrium electrons on deep, non-ionized carbon levels.     

扫描电子显微镜图像漂移的实时矫正方法

为解决扫描电子显微镜(SEM)由于电子束漂移、电磁干扰等原因导致的图像漂移问题,提出基于ORB结合PROSAC的图像漂移矫正算法。首先采用ORB算法对基准图像和实时图像进行特征检测,然后利用汉明距离与交叉匹配实现特征的初匹配,再结合RANSAC的优化算法PROSAC计算帧间的单应矩阵,利用单应矩阵映射剔除外点后重新迭代计算出最终的精确单应矩阵,最后利用单应矩阵的透视变换实现SEM图像漂移实时矫正。通过实验证明,该算法不仅精度高,而且能够满足SEM实时处理的要求。     

Electronic structure of hydrogen in Al

The impurity induced charge density of proton in Al is calculated by solving the Schrödinger equation self-consistently. The lattice contribution and the lattice dilation are included through spherical solid model potential and Blatt correction, respectively. The proton is kept at an octahedral site. The resulting phase shifts have been used to estimate the residual resistivity for dilute Al-H system. This model does not favour the formation of AlH, i.c., hydrogen exists in Al matrix as a free ion.     

Determination of the cascade summation coefficients of gamma quanta for a semiconductor detector in the 59–2754 keV range

A method of measuring the cascade summation coefficients of a semiconductor Ge(Li)-detector with a relative efficiency of 15% without using calculation programs is proposed. An uncertainty of 2% (k = 2) in the cascade summation coefficients obtained for energies of 59–2754 keV is obtained. A method of constructing the overall efficiency curve of the detector up to an energy of 2754 keV using ⁶⁰Co, ⁸⁸Y, and ²⁴Na radionuclides is proposed. The measured cascade summation coefficients are compared with those calculated using the ETNA program (LNHB, France). __________ Translated from Izmeritel’naya Tekhnika, No. 9, pp. 58–62, September, 2006.     

电子背散射衍射的测试技术进展

电子背散射技术(EBSD)因可以获得晶体结构和取向信息而成为SEM的重要补充,在金属、半导体、矿物和陶瓷材料等领域的作用日益重要.更高的分辨率、更高的速度和效率是对EBSD技术提出的发展需求.本文在简述EBSD技术基础原理的基础上,重点评述了其在提高空间分辨率(透射菊池衍射(TKD))及提升处理速度和表征效率(CMOS...