First experimental research of the bunch compressor at CAEP

Magnetic bunch compressor is one of the key technologies on the path to next generation accelerator driven facilities. In this paper we report the design principles and the first experimental research of the bunch compressor developed at Chinese Academy of Engineering Physics （CAEP）. The length of the bunch after compressor is found to be about 0.7 ps （rms） and the peak current exceeds 500 A when operated in the optimized condition. The sensitivity of the bunch length on the phase of the acceleration field and magnetic field of the bunch compressor was also measured and analyzed.     

窄带阻抗对束团纵向平衡分布的影响

从电子运动方程出发,得到了Haissinski方程和窄带阻抗感应电压表达式,然后采用分析和数值方法,分共振频率远大于、接近、远小于束团特征频率三种情况,详细分析了窄带阻抗对单束团的静态分布的影响.     

Characteristics of terahertz coherent transition radiation generated from picosecond ultrashort electron bunches

This paper presents a method of generating terahertz (THz) coherent transition radiation (CTR) from picosecond ultrashort electron bunches including single and train bunches, which are produced by a photocathode radio frequency gun. The radiation characteristics of THz CTR including formation factor and energy spectrum are analysed in detail. With the help of a 2-dimensional particle-in-cell simulation, the radiation characteristics including power, energy and magnetic field are analysed. The results show that the radiation frequency can be adjusted by tuning the repetition frequency of the train bunch and the energy can be enhanced with the train bunches.     

Terahertz coherent transition radiation based on an ultrashort electron bunching beam

The experimental result of terahertz (THz) coherent transition radiation generated from an ultrashort electron bunching beam is reported.During this experiment,the window for THz transmission from ultrahigh vacuum to free air is tested.The compact measurement system which can simultaneously test the THz wave power and frequency is built and proofed.With the help of improved Martin-Puplett interferometer and Kramers-Krong transform,the longitudinal bunch length is measured.The results show that the peak power of THz radiation wave is more than 80 kW,and its radiation frequency is from 0.1 THz to 1.5 THz.     

基于现役装置的冲击点火可行性概念研究

以冲击点火物理特性的研究为基础, 分析冲击点火对高功率激光驱动器的物理需求, 然后从总体层面概括给出基于现役装置(神光III等间接驱动中心点火高功率激光装置) 研究冲击点火面临的关键技术问题. 研究表明, 基于现役装置的冲击点火主要面临两个层面的问题, 首先是非均匀光路排布下实现均匀辐照的工程层面问题, 其次是在现役装置上高效实现冲击点火激光脉冲的激光技术层面问题. 通过研究 分别对两个层面的问题提出相应的解决思路, 为后续研究奠定基础.     

紧凑型单能伽马射线源

基于高亮度电子束与超短强激光相互作用的逆康普顿散射X/γ射线源具有单色性好、能量可调、偏振可控等特点,在核安全及核安保领域具有广泛的应用前景。清华大学将研制国际上首套能量达MeV的紧凑准单能伽马源装置并开展包括先进辐射成像、基于核共振荧光的物质分析检测等应用工作。给出该光源设计方案,以及针对其关键性能指标进行的优化及光源最终性能指标。目前已完成光源的设计,正在进行部件的加工采购,预计将于2023年启动装置的安装调试工作,于2025年完成项目的调试和验收。     

汤姆逊硬X射线源中锁模脉冲激光稳频方法

 汤姆逊硬X射线源中,光阴极微波电子枪要求触发激光脉冲与腔中微波场相位的精确时间同步。理论分析了锁模脉冲激光器相位噪声,探讨了对激光脉冲相位探测和控制的方法,并通过实验构建了激光相位抖动测量系统和锁相环稳频回路,用基频鉴相信号驱动压电陶瓷晶体改变谐振腔长,实现了从开环3.42 ps到闭环1.46 ps的均方根相位抖动的测量和控制。     

XIPAF磁铁电源电流纹波对慢引出的影响

从理论和模拟两方面研究了西安质子应用装置二极铁、四极铁电源电流纹波对引出束流的影响,并根据模拟结果确定出以下单种磁铁电源电流纹波标准：对于聚焦四极铁电源,电流纹波/设定值应小于1.2×10^-4;对于散焦四极铁电源,电流纹波/设定值应小于2×10^-3;对于二极铁电源,电流纹波/设定值应小于4×10^-4。因西安质子应用装置同步环上所有磁铁电源采用同一纹波标准,综合考虑所有磁铁电源电流纹波后,最终确定电源电流纹波/设定值应小于1×10^-4。     

A simulation study of Tsinghua Thomson scattering X-ray source

Thomson scattering X-ray sources are compact and affordable facilities that produce short duration, high brightness X-ray pulses enabling new experimental capacities in ultra-fast science studies, and also medical and industrial applications. Such a facility has been built at the Accelerator Laboratory of Tsinghua University, and upgrade is in progress. In this paper, we present a proposed layout of the upgrade with design parameters by simulation, aiming at high X-ray pulses flux and brightness, and also enabling advanced dynamics studies and applications of the electron beam. Design and construction status of main subsystems are also presented.