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arXiv · 2202.09455

Analysis of photoinjector transverse phase space in action and phase coordinates

Houjun Qian·Mikhail Krasilnikov·Zakaria Aboulbanine·Gowri Adhikari·Namra Aftab·Prach Boonpornpras·Georgi Georgiev·James Good·Matthias Gross·Christian Koschitzki·Xiangkun Li·Osip Lishilin·Anusorn Lueangaramwong·Raffael Niemczyk·Anne Oppelt·Guan Shu·Frank Stephan·Grygorii Vashchenko·Tobias Weilbach
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Abstract

Photoinjectors are the main high brightness electron sources for X-ray free electron lasers (XFEL). Photoinjector emittance reduction is one of the key knobs for improving XFEL lasing, so precise emittance measurement is critical. It's well known that rms emittance is very sensitive to low intensity tails of particle distributions in the phase space, whose measurement depend on the signal to noise ratio (SNR) and image processing procedures. Such sensitivities make the interpretations of beam transverse brightness challenging, leading to different emittance definitions to reduce the impact of tail particles. In this paper, transverse phase space is analyzed in action and phase coordinates for both analytical models and experiments, which give a more intuitive way to calculate the beam core brightness.

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Houjun Qian, Mikhail Krasilnikov, Zakaria Aboulbanine, Gowri Adhikari, Namra Aftab, Prach Boonpornpras, Georgi Georgiev, James Good, Matthias Gross, Christian Koschitzki, Xiangkun Li, Osip Lishilin, Anusorn Lueangaramwong, Raffael Niemczyk, Anne Oppelt, Guan Shu, Frank Stephan, Grygorii Vashchenko, Tobias Weilbach. 2022-02-18. Analysis of photoinjector transverse phase space in action and phase coordinates. https://doi.org/10.1103/physrevaccelbeams.25.103401

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