Simulation for radiation effects in electronics

Adequate simulation testing for radiation effects requires knowledge of radiation effects mechanisms to relate test environments to operational environments. In order to scale the effect with radiation type, spectrum, or time dependence, the response must be separated into different radiation effects, The basic separation is into displacement, charge-transfer, and ionization effects. Within each category short-lived and long-term responses must be considered. Specific simulation facilities can be used to produce particular combinations of effects. Pulsed and steady-state neutron sources (reactor or accelerators), flash X-ray machines, and electron linear accelerators are particularly useful for producing the effects of the radiation from a nuclear explosion. Steady-state electron and proton accelerators are especially appropriate for simulating space radiation. In the first case the problem is to produce the high radiation rates; in the second to qualify accelerated testing. Many other simulation problems fall between these two limits.     

Basic technology for VLSI (part II)

This paper describes some of the recent work in the field of basic technology at VLSI Cooperative Laboratories. In microfabrication technology, a pair of high-speed electron-beam pattern delineators, electron-beam mask inspection, a pair of electron-beam projection systems, an X-ray lithography system, and electron-beam and X-ray resists are described. Thermally induced microdefects in silicon crystal are analyzed. A plasma etching system, basic testing and evaluation, and basic devices are also discussed.     

Basic Technology for VLSI (Part II)

This paper describes some of the recent work in the field of basic technology at VLSI Cooperative Laboratories. In microfabrication technology, a pair of high-speed electron-beam pattern delineators, electron-beam mask inspection, a pair of electron-beam projection systems, an X-ray lithography system, and electron-beam and X-ray resists are described. Thermally induced microdefects in silicon crystal are analyzed. A plasma etching system, basic testing and evacuation, and basic devices are also discussed.     

A new class of portable X-ray apparatuses based on carbon nanocluster cathodes

Principles of the development of high-power pulsed X-ray sources based on explosive emission from carbon nanoclusters are stated. Designs and main parameters of the developed X-ray tubes ( the electron flow exciting the X-ray radiation is 100?500 А, the voltage is 20?150 kV, the pulse length is 10?20 ns, and the nanosecond pulse repetition rate is 1?10³ Hz) are reported.     

X射线全息术及分辨率

本文论述了限制Ｘ射线全息术分辨率的一些主要因素．在记录过程中，影响Ｘ射线全息术分辨率的主要因素是样品对Ｘ射线的衍射和相干散射、记录方式和Ｘ射线束的相干性．本文分别讨论了上述各因素和Ｘ射线全息术分辨率的关系，指出了Ｘ射线全息术和一般光学全息术的差别．在再现过程中，影响Ｘ射线全息术分辨率的因素主要有两个，一个是探测工具的分辨率低于Ｘ射线全息图干涉条纹的空间频率，另一个是像差．本文着重讨论了在探测工具的分辨率高于Ｘ射线全息图干涉条纹空间频率的条件下像差和Ｘ射线全息图分辨率的关系，以及如何消除像差等间题．     

独立源和受控源的异同点

“电路基础”对于高等学校电类专业学生来说,是一门重要的学科基础课,其中受控源是基础知识部分的一个难点,本文从受控源和独立源的定义出发,结合思维导图,在是否为激励源、端口情况、等效电路和在叠加定理的应用四个方面深入分析了受控源和独立源的不同之处,从“源”的角度阐述受控源和独立源的相同点,同时分别给出了四种受控源的原型电路实例,分析了受控源供出能量的来源,旨在为学习者深刻理解受控源提供帮助。     

产生毫微秒脉冲高压的螺旋形带状线发生器的研究

本文叙述了能产生毫微秒脉冲高压的螺旋形带状线发生器(以下简称SSLG)的基本原理,给出了具有一个短路开关,内端为高压输出端,外端接地的SSLG的设计方法,并提供了为便携式X光发生器设计的SSLG的制作工艺。对该发生器电性能的实验研究表明:该发生器能输出脉宽40100ns、电压100kV的高压脉冲,接上X光管负载时,在距X光管输出窗1m处能得到4070R的X光辐照量。     

Geophysical imaging with arbitrary source illumination

Geophysical diffraction tomography is a technique for quantitative, high-resolution, subsurface imaging. This approach to imaging is a generalization of the conventional backprojection algorithm of X-ray tomography accounting for the diffraction effects that result from longer wavelength seismic or electromagnetic waves necessary for geophysical remote sensing. A diffraction tomography algorithm is presented for a configuration in which a finite number of sources of arbitrary character are distributed along one line and a finite number of receivers are distributed along a line having an arbitrary orientation with respect to the source line. Since most geophysical sources may be reasonably represented as point sources, the two-dimensional form of the algorithm is implemented for cylindrical-beam (a point source in two dimensions) illumination. Numerical experiments are performed to investigate a range of source-receiver configurations. It is found that parallel source and receiver arrays, a cross-borehole configuration, provide better image quality than orthogonal arrays     

Potentially hazardous microwave radiation source--a review.

An increasing proliferation of microwave sources and their continuously broadening scope of applications result in the necessity of an assessment of the potential radiation hazard in various situations. Recently, there has appeared quite a large number of references dealing with specific sources. This paper provides a review of various microwave radiation sources to assist in a general understanding of the basic characteristics of the sources which are pertinent to microwave radiation hazards.     

Application of Radioactive Isotopes for Beta-Voltaic Generators

The features of using radioactive isotopes when creating off-line power supplies are considered. The analysis of the substances used in radioisotope thermoelectric generators (RTGs) is carried out. The prospects for manufacturing beta-voltaic generators are justified and they are compared with other electric power sources. The mechanism of β-decay and its place among other types of nuclear transformations is considered. The basic requirements for radiation safety and the used materials of the frame and converter are formulated. Some designs of radioisotope beta-voltaic sources proposed earlier are considered. A list of isotopes that can be used as a power source in a beta-voltaic generator is presented. The methods for obtaining the radioactive materials demonstrating β-decay and their basic properties and natural isotopes are considered. It is concluded that the choice of nickel-63 isotope is preferable for use in beta-voltaic generators due to the optimal combination of its half lifetime, average particle energy, and radiation intensity.     

A review of optically pumped NMMW lasers

Near-millimeter-wave (NMMW) gas lasers, which are optically excited with a CO2pump laser, are currently the major sources of coherent radiation in the NMMW region (100 to 1000 GHz). These molecular sources are especially useful at NMMW frequencies > 300 GHz where conventional millimeter-wave sources have serious disadvantages. Optically pumped NMMW lasers can provide tens of milliwatts of CW power of very high spectral purity or megawatts of pulsed power with a broader spectral bandwidth. The state of the art of these lasers, with an emphasis on CW operation, is reviewed. Included are discussions of basic principles of operation, design, and approaches to building laser systems with sufficient power and stability for useful application. Some of the uses of NMMW lasers and some current research efforts on these sources are described.     

Collimator effects in high resolution x-ray computed tomography

This paper complements other studies in the field of image restoration in X-ray computed tomography by including the source collimator among the sources of image degradation. The overall blur is describable in terms of a space variant 2-D impulse response or point spread function, which is initially calculated for an arbitrary scanning eccentricity, a uniform source intensity distribution, a uniform detector sensitivity, and arbitrary collimator aperture and position, and subsequently derived for more complicated sources and detectors. Numerous 3-D hidden-line displays are used throughout to illustrate the complicated 2-D functions emerging from the analysis.     

雷电辐射源定位的时间反转方法与应用

将频域时间反转（time reversal，TR）聚焦技术应用于雷电辐射源探测定位，介绍了雷电辐射源探测系统的基本组成和TR定位算法，讨论了定位精度的影响因素，给出了典型应用实例.通过与传统的方法进行对比，发现该方法具有较好的鲁棒性，无需提取波形的到达时刻等信息，可直接利用检测波形的反向传播进行自动聚焦定位，并具有多辐射源同时定位的潜力.     

Catalytic Generators: Current Status

This paper analyzes the current status and anticipated trends in using catalysts for the production of ecologically clean thermal and electrical energy. Peculiarities of catalytic heat sources in thermogenerators and basic approaches for widening the scope of their application are discussed.     

Thermal galactic sources

Celestial radio sources have generally been divided into two categories: 1) thermal sources, and 2) nonthermal sources. The thermal sources are usually masses of ionized hydrogen and their radiation is due to the random interaction of the electrons and protons of the ionized gas. The major cause of ionization is the ultraviolet radiation of the hot stars. This paper describes the basic physical processes involved in the radiation, and the methods of obtaining information from radio observations about the interstellar medium and the hot stars.     

Some thought-experiments in reliability

Five thought-experiments are presented which address the relationships between life distributions and physical processes. These relationships are sources of basic misconceptions in the reliability literature     

Laser-heated X-ray flashlamp brightness measurements

We present measurements of the X-ray emission characteristics of laser-irradiated flashlamp foils which are candidates to produce by resonant photoexcitation a population inversion in either a neon or fluorine lasant gas. Using the Shiva 1.06 μm laser, we heated Fe, Cr, and Ni foils to study tile brightness and centroid energies of X-ray lines stemming fromL-Mtransitions. Results indicate that appropriately bright and uniform sources can be produced.     

单片机构成的仿真信源发生器

文章论述了可用于ATM网络研究和测试的多媒体仿真信源发生器的设计思想,基本原理和软硬件结构。     

Advances in pulsed power-driven radiography systems

Flash X-ray radiography has undergone a transformation in recent years with the resurgence of interest in compact, high-intensity pulsed power-driven electron beam sources. The radiographic requirements and the choice of consistent X-ray sources determine the driver requirements, which can be met by demonstrated induction voltage adder technologies. This paper reviews the state of the art, the critical technologies, and the recent advances which have improved performance by over an order of magnitude in beam brightness and radiographic utility.     

GaAs／GaAlAs阴极粘结工艺的X射线双晶衍射测量

分析了ＧａＡｓ／ＧａＡｌＡｓ阴极粘结工艺中应力产生的根源和晶体中应力对Ｘ射线双晶衍射峰的宽度和强度的影响。用Ｘ射线双晶衍射仪测量了阴极和玻璃热粘结工艺过程中阴极材料外延层和衬底的双晶回摆曲线。