Schottky barrier diode as an infrared low-level detector

If collisions between carriers and the lattice can be neglected for the space charge region of a Schottky barrier diode (thermionic mode of operation) the infrared response of the diode, when operating as a low-level quadratic detector, has been calculated. It is shown that the limitation in the infrared response is not so much in the voltage response of the detector, but is caused by the large input conductance of the device caused by carriers that have insufficient energy to reach the metal contact.     

Spin physics with internal targets and the blast detector

The aim of this paper is to give a set of central elements of the algebras U_q(so_m) and U _q(iso _m ) when q is a root of unity. They are surprisingly arise from a single polynomial Casimir element of the algebra U_q(so₃). It is conjectured that the Casimir elements of these algebras under any values of q (not only for q a root of unity) and the central elements for q a root of unity derived in this paper generate the centers of U_q(so_m) and U _q(iso _m ) when q is a root of unity.     

一种基于热离子二极管的大功率微波探测器

主要给出了波导型的X波段大功率微波探测器的结构、标定方法和标定结果。该新型大功率微波探测器具有承受微波峰值功率高（可达100 kW）,时间响应快（响应时间小于2.0 ns）,不需要同步信号,抗干扰能力强等特点。根据不同的需要,可以制作成波导型和同轴型的大功率微波探测器。波导型探测器由热离子二极管、标准波导、滤波器和外电路组成,其工作频率范围为波导的工作频率范围;而同轴型探测器由热离子二极管、同轴波导,滤波器和外电路组成,可以宽带使用。标定结果表明该探测器很适合高功率微波峰值功率测量,尤其是在强电磁干扰环境和高重频微波脉冲条件下的测量,为解决功率测量不准的技术难题提供一种有效的技术手段。     

一种基于热离子二极管的大功率微波探测器

 主要给出了波导型的X波段大功率微波探测器的结构、标定方法和标定结果。该新型大功率微波探测器具有承受微波峰值功率高（可达100 kW）,时间响应快（响应时间小于2.0 ns）,不需要同步信号,抗干扰能力强等特点。根据不同的需要,可以制作成波导型和同轴型的大功率微波探测器。波导型探测器由热离子二极管、标准波导、滤波器和外电路组成,其工作频率范围为波导的工作频率范围;而同轴型探测器由热离子二极管、同轴波导,滤波器和外电路组成,可以宽带使用。标定结果表明该探测器很适合高功率微波峰值功率测量,尤其是在强电磁干扰环境和高重频微波脉冲条件下的测量,为解决功率测量不准的技术难题提供一种有效的技术手段。     

Germanium detector with an internal amplification for investigating rare processes

A device of a new type—a germanium detector with an internal amplification—is proposed. Having the effective threshold of about 10 eV, the detector opens up a fresh opportunity for investigating dark matter, measuring the neutrino magnetic moment, exploring coherent neutrino scattering off nuclei, and studying the solar-neutrino problem. The design of the germanium detector with an internal amplification and prospects for its use are described.     

Experiments with Enhanced Mode Thermionic Converters

Reduction of the ionization and scattering losses associated with ignited mode cesium diodes is essential for high thermal-to-electrical conversion efficiency. Use of an auxiliary electrode in conjuction with a noble gas in the interelectrode space should permit more efficient ion generation for space charge neutralization. The characteristics of a thermionic triode utilizing a ring electrode and a dispenser cathode emitter have been studied as a function of xenon pressure, cesium reservoir temperature, spacing, electrode temperature and pulse parameters (i.e., potential, duration and repetition rate) applied to the auxiliary electrode. Pulsed operation significantly enhanced output power with uniform discharges appearing to be sustained at emitter-collector spacings as low as 0.5 mm.     

基于Ritz-Galerkin方法的太赫兹二极管检波器非线性分析

肖特基二极管检波器是太赫兹ASK/OOK通信系统的关键器件之一, 为了更好地分析肖特基二极管检波器的非线性特性, 从检波器的电路模型出发, 基于Ritz-Galerkin方法, 建立了检波器非线性特性的理论分析模型。并利用模型对检波器输出信号强度和灵敏度作了理论预测, 表明该理论模型能够精确预测检波器的非线性特性。最后利用该理论模型研究了输入信号强度、负载阻抗和外界温度对0.34 THz肖特基二极管检波器非线性特性的影响。结果表明随着功率的增加, 检波器由平方率区渐变至线性区只在特定条件下才成立, 在实际条件下很容易出现高阶效应。     

Intersubband transition in quantum wells and triple-barrier diode infrared detector concepts

We present effective mass theory results for intersubband transition energies, oscillator strengths, and other quantities which are relevant to the design of quantum well devices. Results are presented in the form of contour plots for easy reference. Theory gives good agreement with existing experimental data by various research groups. In addition, a new quantum well infrared detector is proposed, which employs resonant tunneling in a triple-barrier diode. The device has a narrow bandwidth controlled by the resonance width and a very low dark current making high temperature (> 77 K) operation possible.     

基于Ritz-Galerkin方法的太赫兹二极管检波器非线性分析

肖特基二极管检波器是太赫兹ASK/OOK通信系统的关键器件之一, 为了更好地分析肖特基二极管检波器的非线性特性, 从检波器的电路模型出发, 基于Ritz-Galerkin方法, 建立了检波器非线性特性的理论分析模型。并利用模型对检波器输出信号强度和灵敏度作了理论预测, 表明该理论模型能够精确预测检波器的非线性特性。最后利用该理论模型研究了输入信号强度、负载阻抗和外界温度对0.34 THz肖特基二极管检波器非线性特性的影响。结果表明随着功率的增加, 检波器由平方率区渐变至线性区只在特定条件下才成立, 在实际条件下很容易出现高阶效应。     

Quantum Zeno effect in spontaneous decay with distant detector

A numerical model of spontaneous decay which is continuously observed by a distant detector of emitted particles is constructed. It is shown that there is no quantum Zeno effect in such quantum measurement if the interaction between the emitted particles and the detector is short-range and the mass of emitted particles is not zero.     

Low frequency characteristics of a quasioptical Schottky diode detector part I: Theory

A theoretical study is made of saturation effects of FIR point contacts Schottky diodes when used in the envelope detection mode of operation. A model is described that fits experimental results for radiation wavelength ranging from microwaves down to FIR wavelengths. This model permits the prediction of saturation levels throughout this range.     

Heterodyne performance of a quasioptical Schottky diode detector: Theoretical and experimental results

A detailed theoretical and experimental study of the heterodyne performance of a quasioptical Schottky diode detector is presented. The experimental results have been obtained by mixing the radiation from a FIR laser with the output of a 67–73 GHz Klystron. The heterodyne signal variation versus various parameters and its relation to the special case of two lasers mixing are described. The mixer characteristics are a NEP value of 2×10^–19W/Hz and a detector bandwidth of at least 9 GHz. Experimental evidence of harmonics generation of submillimetric frequencies at the diode junction is also presented.     

Brownian diode: Molecular motor based on a semi-permeable Brownian particle with internal potential drop

A model of an autonomous isothermal Brownian motor with an internal propulsion mechanism is considered. The motor is a Brownian particle which is semi-transparent for molecules of surrounding ideal gas. Molecular passage through the particle is controlled by a potential similar to that in the transition rate theory, i.e. characterized by two stationary states with a finite energy difference separated by a potential barrier. The internal potential drop maintains the diode-like asymmetry of molecular fluxes through the particle, which results in the particle?s stationary drift.     

Low frequency characteristics of a quasioptical Schottky diode detector part II: Experimental results

A detailed experimental study of the low frequency (video) response of a quasioptical Schottky diode detector over the microwave and FIR wavelength range is presented. An optimization of the responsivity versus the bias current is proposed and a generalized curve of the saturation power versus the FIR wavelength is given. This curve defines for any antenna point-contact Schottky diode detector, suitable for FIR detection, the power range for a linear detector response. A simple method is also described to calculate the coupling efficiency of the laser radiation into the antenna reception pattern.     

Noncontact localized internal infrared radiation measurement using an infrared point detector

The techniques for temperature measurement within the human body are important for clinical applications. A method for noncontact local infrared (IR) radiation measurements was investigated deep within an object to simulate how the core human body temperature can be obtained. To isolate the IR light emitted from a specific area within the object from the external noise, the radiating IR light was detected using an IR point detector, which comprises a pinhole and a thermopile positioned at an imaging relation with the region of interest within the object. The structure of the helical filament radiating IR light inside a light bulb was thermally imaged by scanning the bulb in two dimensions. Moreover, this approach was used to effectively measure IR light in the range of human body temperature using a glass plate placed in front of the heat source, mimicking the ocular fundus.     

基于“猫眼效应”的狙击手光电探测仪

为从技术层面上提高反狙击能力,通过分析狙击步枪瞄准镜的反射特性,利用线阵CCD捕捉瞄准镜回波信号研制出主动式狙击手光电探测仪。介绍了探测仪的主要指标参数,并模拟实际使用环境验证了其探测效果。试验结果表明:在城市作战中狙击手通常伏击的距离为20 m~200 m,探测仪可准确探测微光瞄准镜及口径为32 mm、40 mm、42 mm和50 mm的白光瞄准镜,且不受镜子和手电筒凹面镜等反射体干扰,但对加装蜂窝板的瞄准镜,当距离大于80 m后无法可靠探测。     

Periodic structures in the Franck-Hertz experiment with neon: Boltzmann equation and Monte-Carlo analysis

A new experimental technique for the measurements of the total cross section for electron scattering from atoms and molecules at very low energy is described. Momentum transfer cross sections for scattering from Ar, Kr and Xe at very low energies were carefully derived using the modified effective range theory from the recently measured total cross sections, which were obtained with a new experimental technique utilizing the threshold photoelectron source. A significant discrepancy between the momentum cross sections derived from the present analysis and those determined in the previous electron swarm studies was found at energies below 100 meV. The findings emphasize the need of further high precision experiments in the very low energy region as well as re-analysis of the previous swarm data.     

SiC-pn结二极管α粒子辐射效应

为了研究6H-SiC材料制作的pn结二极管探测器的辐照特性,采用蒙卡程序模拟研究了4.3和1.8 MeV能量的α粒子在辐照探测器中的物理过程。介绍了二极管探测器的工艺制作和物理参数,根据其结构建立了仿真模型,利用蒙卡程序进行了α粒子照射的仿真研究。研究结果直观地反映了α粒子在探测器中的输运情况。α粒子在探测器中的辐射效应主要是电离作用,电离产生的电子-空穴对形成一定的分布。给出了α粒子在探测器中的电离能量损失分布及二极管探测器的电荷收集效率表达式。     

SiC-pn结二极管α粒子辐射效应

为了研究6HSiC材料制作的pn结二极管探测器的辐照特性,采用蒙卡程序模拟研究了4.3和1.8MeV能量的α粒子在辐照探测器中的物理过程。介绍了二极管探测器的工艺制作和物理参数,根据其结构建立了仿真模型,利用蒙卡程序进行了α粒子照射的仿真研究。研究结果直观地反映了α粒子在探测器中的输运情况。α粒子在探测器中的辐射效应主要是电离作用,电离产生的电子空穴对形成一定的分布。给出了α粒子在探测器中的电离能量损失分布及二极管探测器的电荷收集效率表达式。     

The enhanced backscatter effect with the source and detector at finite distances

Numerical results are presented of double-scatter Kirchhoff calculations for the scattering of light from randomly rough surfaces with the source and detector at finite distances. The surfaces considered are one-dimensional perfectly conducting surfaces and shadowing is included explicitly in the calculations. For the case of the source and detector at the same distance, the scattered intensity distribution is insensitive to the value of this distance except when it is of the order of the surface size. In that case the intensity distribution changes but the backscatter enhancement factor stays constant. For the source and detector at different distances, the backscatter enhancement is less than the enhancement for the case of the source and detector at the same distance.