强激光与粒子束
2023, 35(11): 114002
1 电子科技大学 电子薄膜与集成器件国家重点实验室, 成都 610054
2 北京大学 东莞光电研究院, 广东 东莞 523808
3 电子科技大学 广东电子信息工程研究院, 广东 东莞 523808
4 无锡先瞳半导体科技有限公司, 江苏 无锡 214000
雪崩倍增效应是4H-SiC雪崩光电二极管、功率半导体器件等器件的关键机理。作为其中最重要的物理参数，雪崩倍增因子(M)的精确解析表达式目前未见报道。文章提出4H-SiC p-n结M的精确计算方法及其解析表达式。基于更准确的碰撞电离模型，通过MATLAB对4H-SiC单边突变结(p+-n)电子和空穴的碰撞电离积分(I)进行精确的数值计算，给出击穿电压(BV)随掺杂浓度的经验表达式，进一步提出电离积分随外加电压及掺杂浓度的拟合表达式。此外，对外加电压接近BV的情形进行细致的相对误差分析，表明电子电离积分受电场影响显著。对于雪崩光电二极管及功率器件较宽的BV范围，所提出的拟合表达式在外加反向偏压大于0.65BV时具有较高的精确度(相对误差小于5%)。
雪崩倍增因子 碰撞电离积分 Miller公式 4H-SiC 4H-SiC avalanche multiplication factor impact ionization integral Miller formula
强激光与粒子束
2022, 34(12): 124002
强激光与粒子束
2021, 33(4): 044009
Author Affiliations
Abstract
1 Department of Engineering Physics, Tsinghua University, Beijing 100084, China
2 Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
3 Xi’an Jiaotong University, Xi’an 710049, China
4 Institute of Applied Electronics, CAEP, Mianyang 621900, China
High-energy electron radiography (HEER) is a promising diagnostic tool for high-energy-density physics, as an alternative to tools such as X/γ-ray shadowgraphy and high-energy proton radiography. Impressive progress has been made in the development and application of HEER in the past few years, and its potential for high-resolution imaging of static opaque objects has been proved. In this study, by taking advantage of the short pulse duration and tunable time structure of high-energy electron probes, time-resolved imaging measurements of high-energy-density gold irradiated by ultrashort intense laser pulses are performed. Phenomena at different time scales from picoseconds to microseconds are observed, thus proving the feasibility of this technique for imaging of static and dynamic objects.
Matter and Radiation at Extremes
2019, 4(6): 065402
Author Affiliations
Abstract
1 Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
3 School of Science, Xi'an Jiaotong University, Xi'an 710049, China
4 Department of Engineering Physics, Tsinghua University, Beijing 100084, China
The research activities on warm dense matter driven by intense heavy ion beams at the new project High Intensity heavy-ion Accelerator Facility (HIAF) are presented. The ion beam parameters and the simulated accessible state of matter at HIAF are introduced, respectively. The progresses of the developed diagnostics for warm dense matter research including high energy electron radiography, multiple-channel pyrometer, in-situ energy loss and charge state of ion detector are briefly introduced.
Warm dense matter Intense heavy ion beams HIAF Electron radiography Matter and Radiation at Extremes
2018, 3(2): 85
Author Affiliations
Abstract
Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
Recent research activities relevant to high energy density physics (HEDP) driven by the heavy ion beam at the Institute of Modern Physics, Chinese Academy of Sciences are presented. Radiography of static objects with the fast extracted high energy carbon ion beam from the Cooling Storage Ring is discussed. Investigation of the low energy heavy ion beam and plasma interaction is reported. With HEDP research as one of the main goals, the project HIAF (High Intensity heavy-ion Accelerator Facility), proposed by the Institute of Modern Physics as the 12th five-year-plan of China, is introduced.
heavy ion beam high energy density physics ion beam and plasma interaction radiography High Power Laser Science and Engineering
2014, 2(4): 04000e39
1 中国科学院 近代物理研究所， 兰州 730000
2 甘肃省粒子束辐射工程技术研究中心， 兰州 730000
3 甘肃省粒子束辐射工程技术研究中心， 兰州 730000，
为了提高DG型电子加速器束流扫描均匀度、解决束流中心偏移、提升束流引出效率，开发了一种既可实现X,Y两相互垂直方向均匀扫描又可以实现束流中心自动对中调节的扫描系统。介绍了扫描磁铁及其电源参数的选取依据，阐述了将扫描磁铁和束流校正线圈进行整体式设计的扫描系统扫描电流成形方式及自动对中电路信号调制过程，包括为提高加速器运行安全性而设计的连锁保护信号。产业化现场使用事实已证明,该系统设计完全达到了设计要求，具有优良的扫描均匀度和长时间工作稳定可靠性。
电子加速器 扫描电源 扫描磁铁 自校正 扫描均匀度 electron accelerator scanning powersupply scanning magnet selfcorrecting scanning uniformity
1 中国科学院 近代物理研究所， 兰州 730000
2 中国科学院 研究生院， 北京 100049
介绍了介质壁加速器(DWA)的原理和几种可能实现的结构。通过对多层介质圆柱的平面波电磁散射的研究，用FORTRAN语言编写程序计算和分析了DWA加速管三层介质柱体结构的平面波电磁散射的散射宽度与几何结构参数、材料参数的关系，用以优化设计介质壁加速管结构。计算结果表明：当加速管材料和等势环介电常数一定时，平面波电磁散射宽度随半径增大而增大；当加速管内外径一定时，加速管材料和等势环介电常数增大时散射宽度变化不明显，但最小散射宽度显著减小。当加速管半径和材料一定时，总能找到使散射宽度达到最小的等势环介质厚度。
介质壁加速器 加速管结构 介质圆柱散射 散射宽度 能量耦合效率 dielectric wall accelerator structure of beam pipe electromagnetic scattering at dielectric cylinder scattering width energy coupling efficiency
