中国物理B ›› 2017, Vol. 26 ›› Issue (4): 44102-044102.doi: 10.1088/1674-1056/26/4/044102

• ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS • 上一篇    下一篇

Compressing ultrafast electron pulse by radio frequency cavity

Min-Jie Pei(裴敏洁), Da-Long Qi(齐大龙), Ying-Peng Qi(齐迎朋), Tian-Qing Jia(贾天卿), Shi-An Zhang(张诗按), Zhen-Rong Sun(孙真荣)   

  1. 1 State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China;
    2 NYU-ECNU Institute of Physics at NYU Shanghai, Shanghai 200062, China;
    3 Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
  • 收稿日期:2016-07-26 修回日期:2016-11-16 出版日期:2017-04-05 发布日期:2017-04-05
  • 通讯作者: Shi-An Zhang, Zhen-Rong Sun E-mail:sazhang@phy.ecnu.edu.cn;zrsun@phy.ecnu.edu.cn
  • 基金资助:
    Project partially supported by the National Natural Science Foundation of China (Grant Nos. 51132004 and 11474096), the Fund from the Science and Technology Commission of Shanghai Municipality, China (Gant No. 14JC1401500), and the NYU-ECNU Institute of Physics at NYU Shanghai, China.

Compressing ultrafast electron pulse by radio frequency cavity

Min-Jie Pei(裴敏洁)1, Da-Long Qi(齐大龙)1, Ying-Peng Qi(齐迎朋)1, Tian-Qing Jia(贾天卿)1, Shi-An Zhang(张诗按)1,2,3, Zhen-Rong Sun(孙真荣)1   

  1. 1 State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China;
    2 NYU-ECNU Institute of Physics at NYU Shanghai, Shanghai 200062, China;
    3 Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
  • Received:2016-07-26 Revised:2016-11-16 Online:2017-04-05 Published:2017-04-05
  • Contact: Shi-An Zhang, Zhen-Rong Sun E-mail:sazhang@phy.ecnu.edu.cn;zrsun@phy.ecnu.edu.cn
  • Supported by:
    Project partially supported by the National Natural Science Foundation of China (Grant Nos. 51132004 and 11474096), the Fund from the Science and Technology Commission of Shanghai Municipality, China (Gant No. 14JC1401500), and the NYU-ECNU Institute of Physics at NYU Shanghai, China.

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摘要： An ultrafast electron diffraction technique with both high temporal and spatial resolution has been shown to be a powerful tool to observe the material transient structural change on an atomic scale. The space charge forces in a multi-electron bunch will greatly broaden the electron pulse width, and therefore limit the temporal resolution of the high brightness electron pulse. Here in this work, we design an ultrafast electron diffraction system, and utilize a radio frequency cavity to realize the ultrafast electron pulse compression. We experimentally demonstrate that the stretched electron pulse width of 14.98 ps with an electron energy of 40 keV and the electron number of 1.0×105 can be maximally compressed to about 0.61 ps for single-pulse measurement and 2.48 ps for multi-pulse measurement by using a 3.2-GHz radiofrequency cavity. We also theoretically and experimentally analyze the parameters influencing the electron pulse compression efficiency for single- and multi-pulse measurements by considering radiofrequency field time jitter, electron pulse time jitter and their relative time jitter. We suggest that increasing the electron energy or shortening the distance between the compression cavity and the streak cavity can further improve the electron pulse compression efficiency. These experimental and theoretical results are very helpful for designing the ultrafast electron diffraction experiment equipment and compressing the ultrafast electron pulse width in a future study.

关键词: ultrafast electron diffraction, electron pulse compression, radio frequency cavity

Abstract: An ultrafast electron diffraction technique with both high temporal and spatial resolution has been shown to be a powerful tool to observe the material transient structural change on an atomic scale. The space charge forces in a multi-electron bunch will greatly broaden the electron pulse width, and therefore limit the temporal resolution of the high brightness electron pulse. Here in this work, we design an ultrafast electron diffraction system, and utilize a radio frequency cavity to realize the ultrafast electron pulse compression. We experimentally demonstrate that the stretched electron pulse width of 14.98 ps with an electron energy of 40 keV and the electron number of 1.0×105 can be maximally compressed to about 0.61 ps for single-pulse measurement and 2.48 ps for multi-pulse measurement by using a 3.2-GHz radiofrequency cavity. We also theoretically and experimentally analyze the parameters influencing the electron pulse compression efficiency for single- and multi-pulse measurements by considering radiofrequency field time jitter, electron pulse time jitter and their relative time jitter. We suggest that increasing the electron energy or shortening the distance between the compression cavity and the streak cavity can further improve the electron pulse compression efficiency. These experimental and theoretical results are very helpful for designing the ultrafast electron diffraction experiment equipment and compressing the ultrafast electron pulse width in a future study.

Key words: ultrafast electron diffraction, electron pulse compression, radio frequency cavity

中图分类号:  (Electron and positron beams)

  • 41.75.Fr
29.27.-a (Beams in particle accelerators) 52.59.Sa (Space-charge-dominated beams) 61.05.J- (Electron diffraction and scattering)