闪光X射线照相光源的发展

闪光X射线照相是利用加速器产生的短脉冲X射线对快速运动的致密客体进行透视照相的技术。概述了闪光X射线照相对X射线的性能要求；回顾了闪光X射线照相及其加速器的发展历程；分析了闪光X射线照相用加速器的发展方向。     

流体物理研究所高功率脉冲技术研究进展

中国工程物理研究院流体物理研究所是中国最早开展高功率脉冲技术研究的单位,文章简要回顾了流体物理研究所50年来在高功率脉冲技术研究方面的研究情况,介绍了中国大型高功率装置的典型代表、新近建成的世界最高水平的直线感应加速器神龙一号装置(20MeV,2.5kA,80ns),以及超高功率装置--正在建设的用于Z箍缩研究的初级实验平台(PTS,8-10MA,90ns).神龙一号是由84个感应腔串接而成的强流脉冲直线感应电子加速器,每个感应腔由Marx高电压发生器和Blumlein脉冲形成线组成的高功率脉冲系统驱动,逐级加速电子束打靶,通过韧致辐射产生强X射线,对武器内爆过程进行瞬态闪光照相.PTS装置是一台基于Marx发生器和水介质脉冲成形技术、由24路相同模块并联构成的超高功率装置,其单路验证性样机已经完成研制并达到设计指标要求,PTS主机的建设正在进行中.文章还介绍了近几十年来在高功率开关、直线感应加速器(LIA)、Z箍缩、脉冲X光机、爆磁压缩技术、重复频率脉冲技术、直线变压器技术、时间分辨快脉冲诊断技术等高功率脉冲技术方面的研究进展.     

高功率粒子束及其应用

本文评价了高功率粒子束的工作原理及其应用:文中以闪光-Ⅰ强流脉冲电子束加速器为例,论述了机器的基本技术和它的工作特性 高功率粒子束目前已经应用到许多重要研究领域。包括:核辐射效应模拟源、闪光X射线照相、高功率激光器研究、惯性约束聚变、高功率微波的产生、离子集体加速等方面。 报告中简述了我国在高功率粒子束加速器建造和开拓应用方面取得的进展。 最后,也指出了高功率粒子束技术今后发展有关的研究课题。     

3.3MeV直线感应加速器的设计和性能

综述3.3MeV直线感应加速器(LIA)的物理工程概貌和束流特性参数测量。所测数据均达到或超过了设计指标。并已成功地做为曙光一号自由电子激光器出光实验的电子束源。目前,拟串接更多的加速组元使加速器的电子束能量达到10MeV,以便同时用于自由电子激光研究和闪光X射线照相。     

中国脉冲功率科技进展简述

从脉冲功率科学技术的基本内涵出发,回顾我国脉冲功率发展历史,按照高功率脉冲加速器建设历程,我国脉冲功率技术发展史可大致分成三个阶段:自主创业、加速成长到创新超越;尝试以国际视野介绍我国在闪光照相、Z箍缩、高功率微波、电磁发射和工业应用等方面的发展成就;简要阐述脉冲功率技术未来发展趋势,建议大力发展先进辐射源技术,关注爆磁压缩技术,加强HPM、抗核加固和电磁发射等各类负载技术攻关,加大协同创新和应用推广。     

直线感应加速器组元的双脉冲改造

对单脉冲直线感应加速器(LIA)的加速组元进行了双脉冲改造的初步尝试，用铁氧体作为磁芯材料，得到了双脉冲的波形数据。闪光X射线照相在对爆轰产物流体力学性质的研究中有着重要作用，而要得到足够计量的X射线，需要用能量达10～20MeV，强度达千安量级的电子束来轰击靶核；为使得到的照片有足够的分辨率，轰击点(焦斑)直径最大只能为几个毫米。要加速产生合乎要求的电子束，通常依靠大型的LIA。     

闪光Ⅰ号应用于X射线爆轰照相——研究金属射流的穿甲效应

闪光X射线照相技术是研究动载荷及其效应的重要测试手段,特别适用于研究物质在爆炸作用下的瞬变过程,本文介绍了闪光Ⅰ号加速器应用于X射线爆轰照相的基本状况,以及用于观察金属射流穿过高密度物质钨靶的实验技术。     

神龙二号加速器及其关键技术北大核心CSCD

神龙二号加速器是一台以M H z 猝发率猝发工作的三脉冲直线感应电子加速器.该加速器输出的三脉冲电子束,相邻两脉冲间最小时间间隔300 n s ,而且可调,每个脉冲电子束的电子能量1 8 -20 M e V 、束流强度大于等于2 k A .当电子束与轫致辐射转换靶相互作用时,可产生三个强X 光脉冲,X 光斑点尺寸小于等于2 m m （ F W H M ）,距靶1 m 处照射量大于等于7 . 7 4 × 1 0^- 2C /k g （ 0 0 R ）.该加速器涉及的主要关键技术包括三脉冲功率源设计、三脉冲强流高品质电子束源的产生、加速场建造、束流传输线设计、轫致辐射转换靶设计、测量与诊断技术等.     

小型闪光X射线机研究进展综述

闪光X射线照相常用来拍摄高速运动物体的内部结构与流体动力学行为,也逐渐拓展到工业探伤、精密系统状态检测等领域。概述了小型闪光X射线机的研究历程与进展,包括Marx发生器、脉冲形成线、快脉冲直线型变压器、高压变压器4种主要技术路线与开关、 X射线二极管2种关键元器件,讨论了小型闪光X射线照相系统的研究现状,探究了国外成熟的商业小型X光机与国内商业产品的不足,分析了小型闪光X光机将来的发展趋势,为小型闪光X射线机的研发和商业普及探索提供参考。     

“神龙一号”直线感应加速器物理设计

 介绍了 “神龙一号”直线感应加速器物理设计的主要考虑。“神龙一号”加速器是一台电子直线感应加速器，由3.6MeV感应迭加型注入器、72个感应加速腔、脉冲功率系统、束流输运和聚焦系统、控制系统和真空、绝缘油、绝缘气体以及去离子水系统组成。能产生20MeV、束流大于2.5kA，脉冲宽度为60ns的强流脉冲电子束，X光焦斑均方根直径为1.5mm。     

Rapid nucleation of diamond films by pulsed laser chemical vapor deposition

The nucleation of diamond films could be greatly enhanced on mirror-polished Si substrate by a pulsed Nd:YAG laser beam without any thermal- and plasma-assisted processes during a very short time. The nucleation density increased with decreasing laser power density from 1.38×10¹⁰ to 1.17×10⁹ W/cm² and deposition pressure from 1013 to 4 mbar. The pulsed laser beam made no contribution to enhance nucleation at substrate temperature as low as 650°C. X-ray diffraction measurements showed the (1 1 1) diffraction peak of diamond for the samples obtained using only pulsed laser during 40 min. The enhanced nucleation and growth of diamond crystallites were attributed to effective excitation of reactive gases and etching of non-diamond carbon phases by the pulsed laser beam.     

高重复频率脉冲功率技术及其应用:(6)代表性的应用

综合介绍了高重复频率脉冲功率在材料、环保、生物·医疗、光源和高能加速器领域的代表性应用。采用脉冲功率的离子注入和表面改性已经被用于工业产品。废气和废液处理的研究成果正在向实用化接近。使用脉冲电场的杀菌和癌症治疗正在吸引很多学者和厂家,因此脉冲功率在生物医学领域的应用前景是非常乐观的。另外,决定未来集成电路工艺标准的极紫外光源已逐步走向生产线。高能加速器上的闸流管会渐渐被功率半导体器件取代。     

Inductive energy technology for pulsed intense X-ray sources

Defense Special Weapons Agency (DSWA) has been developing inductive energy storage technology (IES) for applications requiring short pulses of X-rays with peak radiation power in the terawatt range. The purpose of this program is to develop more compact and affordable pulsed power sources and power flow technology needed for efficient conversion of the electromagnetic energy into radiation. Performance characteristics of present generators and power conditioning for future pulsed power IES designs are discussed. Because of the complex physics governing the interaction among the power conditioning, power flow, and load performance, DSWA supports studies of power flow to the load that converts the electromagnetic energy to X-ray radiation. Experiments performed at high power levels and resulting improvements in performance are reported     

Conceptual design of an intense positron source based on an LIA

Accelerator based positron sources are widely used due to their high intensity. Most of these accelerators are RF accelerators. An LIA (linear induction accelerator) is a kind of high current pulsed accelerator used for radiography. A conceptual design of an intense pulsed positron source based on an LIA is presented in the paper. One advantage of an LIA is its pulsed power being higher than conventional accelerators, which means a higher amount of primary electrons for positron generations per pulse. Another advantage of an LIA is that it is very suitable to decelerate the positron bunch generated by bremsstrahlung pair process due to its ability to adjustably shape the voltage pulse. By implementing LIA cavities to decelerate the positron bunch before it is moderated, the positron yield could be greatly increased. These features may make the LIA based positron source become a high intensity pulsed positron source.     

The X-1 Z-pinch driver

X-1 is a program initiative to develop the next-generation laboratory X-ray source using fast Z-pinch drivers. X-1 will provide unique applications utility to high-energy density physics, inertial confinement fusion, and radiation effects simulation research. The advent in the 1980's of pulsed power accelerators capable of delivering tens of terawatts to imploding plasma loads led to a quantum improvement in Z-pinch performance by reducing the implosion time to less than 100 ns. Further progress in Z-pinch performance capabilities was achieved in 1996, using a cylindrical wire-array load, and led to the production of 85 TW, 350-500 kJ of X-rays using the Saturn accelerator at Sandia. The PBFA-II accelerator has been converted to drive Z-pinch loads (PBFA-Z), and will provide a factor of 2 increase in current, and 4 in energy, over that provided by Saturn. X-1 is the next step beyond PBFA-Z and, as presently envisioned, represents a factor of 8 increase in energy. It will require a ~360 TW, ~100 ns pulsed power generator to impart ~16 MJ kinetic energy to the reference imploding plasma load. A baseline concept for X-1 has been developed. It utilizes a highly modular, robust architecture with demonstrated performance reliability     

Photoconductive semiconductor switches

Optically activated GaAs switches operated in their high-gain mode are being used or tested for pulsed power applications as diverse as low-impedance, high-current firing sets in munitions; high impedance, low-current Pockels cell or Q-switch drivers for lasers; high-voltage drivers for laser diode arrays; high-voltage, high-current, compact accelerators; and pulsers for ground penetrating radar. This paper will describe the properties of high-gain photoconductive semiconductor switches (PCSS), and how they are used in a variety of pulsed power applications. For firing sets, we have switched up to 7 kA in a very compact package. For driving Q switches, the load is the small (30 pF) capacitance of the Q switch which is charged to 6 kV. We have demonstrated that we can modulate a laser beam with a subnanosecond rise time. Using PCSS, we have demonstrated gain switching a series-connected laser diode array, obtaining an optical output with a peak power of 50 kW and a pulse duration of 100 ps. For accelerators, we are using PCSS to switch a 260 kV, 60 kA Blumlein. A pulser suitable for use in ground-penetrating radar has been demonstrated at 100 kV, 1.3 kA. This paper will describe the specific project requirements and switch parameters in all of these applications, and emphasize the switch research and development that is being pursued to address the important issues     

基于Marx自激监测控制的闪光照相试验可靠性提高技术研究

强流直线感应加速器（LIA）主要应用于闪光照相试验，对其工作可靠性的要求很高。但LIA中包含了庞大的高电压脉冲功率系统，在充电及等待时期，存在发生自激的可能性，从而导致试验失败，并造成重大经济损失及严重影响。从对Marx等装置发生自激后进行立即监测控制的角度，提出了一种提高闪光照相试验可靠性的方法，并研制了可靠性高、适应各种高压放电装置的无源放电检测探头，采用大规模可编程集成电路作为系统中的逻辑处理单元，提高了系统集成度，降低了线路的复杂程度，降低了系统调试的难度，研制的监测控制器可方便地进行监测路数的扩充，适应多达几十路放电装置的检测与监控。功率系统装置自激后，自激监测控制系统响应速度快，最快可以达到100 ns级，且系统抗干扰能力强，满足在闪光试验环境工作的要求，达到了在一定程度上提高闪光照相试验可靠性的目的。     

Pulsed intense electron beams generated in transient hollow cathodedischarges: fundamentals and applications

For the commercial application of pulsed power, material processing with intense pulsed particle beams is a very interesting subject. Recently, high-voltage (1-70 kV), low-pressure (1-100 Pa) transient hollow-cathode discharges turned out to be sources for pulsed intense electron beam generation suitable for this application. The remarkable parameters of these electron beams-beam currents of 50-1000 A (10-30% of the maximum discharge current) with a high energy component (mean energy of about 0.25-0.75 of maximum applied voltage) of 20-70% of the maximum beam current, power density up to 10 W/cm², beam diameters of 0.1-3 mm, beam charge efficiency of 3-5%-captured the attention not only of the scientific community in the last decade. The electron beam is emitted during the early phases of the discharge, and only weak dependence of the high energetic peak of the beam current was found on the external capacity, which determine the development of the later high-current phases. However, the beam parameters depend on the breakdown voltage, gas pressure, and discharge geometry (including self-capacity). In this paper, the characteristics of the pulsed intense electron beams generated in two configurations-multigap pseudosparks and preionization-controlled open-ended hollow-cathode transient discharges (PCOHC)-are described. Such electron beams already were used successfully in a variety of pulsed power applications in material processing, deposition of superconducting (YBaCuO) and diamond-like thin films, microlithography, electron sources for accelerators, and intense point-like X-ray sources, and some preliminary experiments revealed new potential applications such as pumping of short-wavelength laser active media. These pulsed electron beams could be used further in any kind of pulsed power applications that require high-power density, small or high electron energy, and small-beam diameters     

Intense ion beams for inertial confinement fusion

Intense beams of light and heavy ions are being studied as inertial confinement fusion (ICF) drivers for high yield and energy. Heavy and light ions have common interests in beam transport, targets, and alternative accelerators. Self-pinched transport is being jointly studied. This article reviews the development of intense ion beams for ICF. Light-ion drivers are highlighted because they are compact, modular, efficient and low cost. Issues facing light ions are: (1) decreasing beam divergence; (2) increasing beam brightness; and (3) demonstrating self-pinched transport. Applied-B ion diodes are favored because of efficiency, beam brightness, perceived scalability, achievable focal intensity, and multistage capability. A light-ion concept addressing these issues uses: (1) an injector divergence of ⩽24 mrad at 9 MeV; (2) two-stage acceleration to reduce divergence to ⩽12 mrad at 35 MeV; and (3) self-pinched transport accepting divergences up to 12 mrad. Substantial progress in ion-driven target physics and repetitive ion diode technology is also presented. Z-pinch drivers are being pursued as the shortest pulsed power path to target physics experiments and high-yield fusion. However, light ions remain the pulsed power ICF driver of choice for high-yield fusion energy applications that require driver standoff and repetitive operation