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超快电子衍射装置的束流能量反馈控制

张俊强 李林 刘亚娟 江涛 肖诚成 顾强 向导

张俊强, 李林, 刘亚娟, 等. 超快电子衍射装置的束流能量反馈控制[J]. 强激光与粒子束, 2020, 32: 064001. doi: 10.11884/HPLPB202032.190415
引用本文: 张俊强, 李林, 刘亚娟, 等. 超快电子衍射装置的束流能量反馈控制[J]. 强激光与粒子束, 2020, 32: 064001. doi: 10.11884/HPLPB202032.190415
Zhang Junqiang, Li Lin, Liu Yajuan, et al. A beam energy feedback for ultrafast electron diffraction facility[J]. High Power Laser and Particle Beams, 2020, 32: 064001. doi: 10.11884/HPLPB202032.190415
Citation: Zhang Junqiang, Li Lin, Liu Yajuan, et al. A beam energy feedback for ultrafast electron diffraction facility[J]. High Power Laser and Particle Beams, 2020, 32: 064001. doi: 10.11884/HPLPB202032.190415

超快电子衍射装置的束流能量反馈控制

doi: 10.11884/HPLPB202032.190415
基金项目: 国家自然科学基金项目(11327902);国家重点研发计划(2018YFF0109203)
详细信息
    作者简介:

    张俊强(1974—),男,博士,高级工程师,从事加速器微波及低电平系统的研究;zhangjunqiang@zjlab.org.cn

    通讯作者:

    李 林(1986—),男,博士,助理研究员,从事加速器低电平系统的开发;lilin@zjlab.org.cn

  • 中图分类号: TP274

A beam energy feedback for ultrafast electron diffraction facility

  • 摘要: 上海交通大学的超快电子衍射(UED)装置由一台电子直线加速器作为驱动,电子枪为一台光阴极微波电子枪。加速器在运行中电子枪会偶尔打火,腔体失谐,造成束流损失,束流能量产生变化,束流需要很长时间才能恢复到初始状态,影响了用户的使用。为此,对低电平控制器(LLRF)的幅度相位控制环路进行了改进,增加了能量反馈,代替了幅度反馈,通过对束流的中心位置进行实时的反馈以控制低电平控制器输出信号的幅度,保证了电子束流的能量稳定和电子枪加速场强的稳定。长时间的稳定性测试表明,电子枪在打火产生时,束流能量可以很快恢复,能量抖动由4.293 3×10−4(RMS)提高到2.855 7×10−4(RMS),实现了束流能量的长期稳定。
  • 图  1  直线加速器布局

    Figure  1.  Layout of a 1 Mev linear accelerator

    图  2  束流测量

    Figure  2.  Beam measurement data

    图  3  Pickup信号幅度和束流中心位置

    Figure  3.  Pickup amplitude and beam center position

    图  4  低电平系统框图

    Figure  4.  Layout of LLRF system

    图  5  能量反馈的算法

    Figure  5.  Algorithm of energy feedback

    图  6  低电平长期稳定性测试

    Figure  6.  Long term stability test for LLRF

    图  7  束流长期稳定性测试

    Figure  7.  Long term stability test for beam

    图  8  束流能量对电子枪打火的响应

    Figure  8.  Beam energy response to RF gun arc

    表  1  直线加速器性能表

    Table  1.   Main parameters of linear accelerator

    characteristicsworking frequency/GHzrepetition rate/Hzamplitude stability/%phase stability/(°)klystron power/MW
    S-band2.85610~100<0.08<0.095
    C-band5.71210~100<0.08<0.095
    下载: 导出CSV

    表  2  上海交通大学与SLAC的UED性能比较[3,14-15]

    Table  2.   UED performance comparison between SJTU and SLAC

    institutionenergy/MeVenergy spread/%normalized
    emittance/nm·rad
    energy stability/%charge/pCbunch
    length/ps
    amplitude
    stability/%
    phase
    stability/(°)
    SLAC40.066200.0230.10.150.050.04
    SJTU30.050900.060.440.060.03
    下载: 导出CSV
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    Lu Xianhai. Optimization study and application exploration of mega-electron-volt ultrafast electron diffraction. Beijing: Tsinghua University, 2015: 7-10
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    [15] SLAC ultrafast electron diffraction facility[EB/OL].https://lcls.slac.stanford.edu/instruments/mev-ued.
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出版历程
  • 收稿日期:  2019-10-23
  • 修回日期:  2020-01-14
  • 刊出日期:  2020-05-12

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