一种HgCdTe探测器微型杜瓦的设计和工艺研究

介绍一种用于冷却HgCdTe探测器微型制冷杜瓦组件,该组件由旋转马达驱动型斯特林制冷机冷却,杜瓦采用插入式结构,制冷机与杜瓦之间用耦合单元来传递冷量。设计中的关键技术是尽可能减少漏热损失、高效传递冷量以降低斯特林制冷机的热负荷,同时为了达到长期保持杜瓦内真空度的要求,制造过程中还需要进行一系列的工艺处理。本文重点介绍插入式杜瓦用于冷却HgCdTe探测器芯片的结构设计以及工艺解决方案。     

On the optimum thickness of a photoconductive detector: A 0.1 eV HgCdTe detector

The effect of the variation of detector thickness on the voltage responsivity, g-r noise and the specific detectivity of a 0.1 eV HgCdTe photoconductive detector has been calculated. The results of these calculations show that the optimum thickness of the detector should be determined by the diffusion length of the minority carriers rather than the optical absorption coefficient.     

Trade-offs and difficulties of the vertical photoconductor: a novel device structure suitable for HgCdTe two-dimensional infrared focal plane arrays

Recently Siliquini and Faraone [J.F. Siliquini, L. Faraone, Infrared Phys. Technol. 38 (1997) 205] have proposed vertical photoconductive device (PC) based two-dimensional long wavelength infrared region focal plane arrays (LWIR FPAs). In this note, we examine some trade-offs and difficulties of this proposed structure.     

PV型HgCdTe线阵探测器的光学串扰

针对MCT红外焦平面阵列器件普遍存在的光串扰问题进行研究,从器件内部结构上,建立了线阵器件理论计算模型,并基于载流子连续性方程,利用Comsol软件对光串扰的大小进行了数值定量计算,研究了不同探测器结构尺寸、温度和材料等参数对光串扰的影响;从器件外部结构上,利用几何光学,研究了外部光学结构对光串扰的影响。研究结果表明,器件内部的衬底外延层厚度与器件外部的真空层对光串扰的影响最大,为今后红外焦平面器件结构的改进提供了一定的理论指导。     

Optical characterization of defects in narrow-gap HgCdTe for infrared detector applications

Narrow-gap Hg_(1-x)Cd_x Te material with a composition x of about 0.3 plays an extremely important role in mid-infrared detection applications. In this work, the optical properties of doped HgCdTe with x ≈ 0.3 are reviewed, including the defects and defect levels of intrinsic V_(Hg) and the extrinsic amphoteric arsenic(As) dopants, which can act as shallow/deep donors and acceptors. The influence of the defects on the determination of band-edge electronic structure is discussed when absorption or photoluminescence spectra are considered. The inconsistency between these two optical techniques is demonstrated and analyzed by taking into account the Fermi level position as a function of composition, doping level,conductivity type, and temperature. The defect level and its evolution, especially in As-doped HgCdTe, are presented. Our results provide a systematic understanding of the mechanisms and help for optimizing annealing conditions towards p-type As-activation, and eventually for fabricating high performance mid-infrared detectors.     

Induced charge signal of a glass RPC detector

A gas detector glass resistivity plate chamber (GRPC) is proposed for use in the hadron calorimeter (HCAL). The read-out system is based on a semi-digital system and, therefore, the charge information from GRPC is needed. To better understand the charge that comes out from the GRPC, we started from a cosmic ray test to get the charge distribution. We then studied the induced charge distribution on the collection pad. After successfully comparing it with the prototype beam test data at CERN (European Council for Nuclear Research), the process was finally implanted into the Geant4 based simulation for future study.     

Numerical analysis of two-color HgCdTe infrared photovoltaic heterostructure detector

We report on 2D numerical simulations of spectral photoresponse characteristic for two-color HgCdTe infrared photovoltaic detector. Effects of thickness of absorption layer and doping profiles on the photoresponse, quantum efficiency and crosstalk have been investigated. Optimal thickness of absorption layers and doping profiles are numerically calculated.     

Dynamics of a charge qubit coupled with a double-dot detector

We investigate theoretically the dynamics of a charge qubit (double quantum dot system) coupled electrostatically with the double-dot detector. The qubit charge oscillations and the detector current are calculated using the equation of motion method for appropriate correlation functions. In order to find the best detector performance (i.e. the detector current signal follows as well as possible the qubit charge oscillations) we consider different qubit-detector geometries. The optimal setup was found for the qubit lying parallel to the detector quantum dots for which we observed very good detector performance together with weak decoherence of the system. It is also shown that the asymptotic detector current (flowing in response to the limited in time qubit-detector interaction) fully reproduces the qubit dynamics.     

Josephson junction as a detector of poissonian charge injection

We propose a scheme of measuring the non-Gaussian character of noise by a hysteretic Josephson junction in the macroscopic quantum tunneling regime. We model the detector as an (under)damped LC resonator. It transforms Poissonian charge injection into current through the detector, which samples the injection statistics over a floating time window of length approximately Q/omega(J), where Q is the quality factor of the resonator and omega(J) its resonance frequency. This scheme ought to reveal the Poisson character of charge injection in a detector with realistic parameters.     

Modeling of HOT (111) HgCdTe MWIR detector for fast response operation

The paper reports on photoelectrical performance of the mid-wave infrared (MWIR) (111) HgCdTe high operating temperature detector for the fast response conditions. Detector structure was simulated with software APSYS by Crosslight Inc. The detailed analysis of the time response as a function of device architecture and applied voltage was performed pointing out optimal working conditions. The time response of the MWIR HgCdTe detector with 50 % cut-off wavelength of \(\lambda _{c} \approx 5.3\, \upmu \hbox {m}\) at \(T = 200\)  K was estimated at the level of \(\tau _{s} \approx \) 2,500 ps for \(V = 100\)  mV and series resistance \(R_{Series} = 510\,\Omega \) . The series resistance’s reduction enables to reach \(\tau _{s}\approx 60\!-\!500\)  ps.     

Feasibility of creating a specialized reactimeter based on the inverse solution to kinetics equation with a current-mode neutron detector

The file-evaluation results of a reactimeter based on the inverse solution to the kinetics equation (ISKE) are presented, which were obtained using an operating hardware-measuring complex with a KNK-4 neutron detector working in the current mode. The processing of power-recording files of the BR-1M, BR-K1, and VIR-2M reactors of the Russian Federal Nuclear Center—All-Russian Research Institute of Experimental Physics, which was performed with the use of Excel simulation of the ISKE formalism, demonstrated the feasibility of implementation of the reactivity monitoring (during the operation of these reactors at stationary power) beginning from the level of ~5 × 10^–4β_eff.     

激光辐照下PV型HgCdTe探测器反常响应机理

 利用PV型探测器开路电压的表达式,并考虑探测器的温度变化建立模型,对激光辐照下PV型HgCdTe探测器开路电压的变化进行了理论计算。当激光较弱时,计算结果与实验结果符合得很好。当激光较强时,对于辐照过程当中探测器输出变化的一般性趋势以及激光完全停照后的热弛豫过程,该模型也能给出较好的解释;但对于激光开始辐照时输出下跳和激光停止辐照时输出上跳的反常现象,该模型不能给出合理的解释。分析认为,该模型较好地描述了晶格温升对探测器输出的影响,但是它没有考虑热载流子效应;当激光较强时,热载流子效应不可忽略,特别是激光开始辐照和激光停止辐照时,载流子与晶格的温度差有比较明显的快速变化,从而导致了探测器的反常响应。     

Space charge injection into a dipolar glass

Space charges can be injected into dipolar (Li₂B₄O₇)_1?χ(WO₃)_χ glasses with the use of indium electrodes. They can be frozen in and are detected by their thermally stimulated depolarization currents. The large electric fields at the surface induce a ferroelectric domain above a critical field E^crit₀ = 3.8 kV cm^-1. With increasing injection the induced ferroelectricity is destroyed periodically. This is interpreted in terms of the migration of the ferroelectric domain into the interior of the material.     

On a proposed non-integral topological charge solution

It is shown that a recently-proposed solution of theSU(2) gauge theory with topological charge 3/2 is not valid. More generally, integral topological charge solutions are shown to be the only ones possible in a wide class of gauge field structures, which we solve completely.     

一类扰动发展方程近似解

采用了一个简单而有效的技巧, 研究了一类扰动发展方程. 首先引入求解一个相应典型方程的行波孤波解. 然后利用渐近方法得到了原扰动发展方程的近似解. 利用泛函分析的不动点定理, 指出了近似解级数的收敛性, 并讨论了近似解的精度.     

一类广义Sine-Gordon扰动方程的解析解

利用同伦映射方法研究了一类广义Sine-Gordon方程. 首先引入一个同伦变换. 然后构造了原方程解的迭代关系式. 最后得到了问题的解析解. 关键词： 孤子 扰动 同伦映射     

Dynamic range of a thermoplastic photoconductor hologram

A thermoplastic photoconductor material is well-known as a hologram recording material. The dynamic ranges of a thermoplastic hologram are studied in two softening methods. One is the conventional heating method, and the other is the newly developed solvent vapor method. It is found that the solvent vapor method makes the dynamic range ten times as wide as the heating method, and in the solvent vapor method exposure time and charging voltage hardly affect the final diffraction efficiency.     

An invariant solution of the Fokker-Planck equation and rheological equation of state of a macromolecular solution

The Fokker-Planck equation is solved for a soft dumbbell in a homogeneous hydrodynamic field invariantly with respect to rheonomous transformations. The equation of state for a soft dumbbell with relaxation time has the form:P ^ab + ^–1 P ^ab =1/2kTG ^ab .P ^ab is the convected derivative of the stress tensorP ^ab andG ^ab the metric tensor. For a more general model-network composed of Hookean springs with constant hydrodynamic interaction (e.g. a model of Gaussian sub-chains) we obtain the equation of state by combining the contributions of the above-mentioned type. Such an equation of state describes linear visco-elastic behaviour with general spectrum of the relaxation times. If convected derivation with respect to time is used in the calculation, the viscosity is Newtonian even if the calculation is performed in a coordinate system rotating with the molecule.     

A prototype silicon detector system for space cosmic-ray charge measurement

A readout electronics system used for space cosmic-ray charge measurement for multi-channel silicon detectors is introduced in this paper, including performance measurements. A 64-channel charge sensitive ASIC (VA140) from the IDEAS company is used. With its features of low power consumption, low noise, large dynamic range, and high integration, it can be used in future particle detecting experiments based on silicon detectors.