中国物理B ›› 2023, Vol. 32 ›› Issue (5): 53202-053202.doi: 10.1088/1674-1056/ac8cdd

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Theoretical study of the enhancement of saturable absorption of Kr under x-ray free-electron laser

Jiaxin Ye(叶佳鑫)1,2, Yixuan Yang(杨怡璇)3, Chen Yang(杨晨)1,2,†, and Gang Jiang(蒋刚)1,2,‡   

  1. 1 Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China;
    2 Key Laboratory of High Energy Density Physics and Technology, Ministry of Education, Chengdu 610065, China;
    3 College of Electrical Engineering, Sichuan University, Chengdu 610065, China
  • 收稿日期:2022-05-20 修回日期:2022-08-02 接受日期:2022-08-26 出版日期:2023-04-21 发布日期:2023-04-21
  • 通讯作者: Chen Yang, Gang Jiang E-mail:yangchen@scu.edu.cn;gjiang@scu.edu.cn
  • 基金资助:
    Project supported by the Fundamental Research Funds for the Central Universities (Grant No. 10822041A2038).

Theoretical study of the enhancement of saturable absorption of Kr under x-ray free-electron laser

Jiaxin Ye(叶佳鑫)1,2, Yixuan Yang(杨怡璇)3, Chen Yang(杨晨)1,2,†, and Gang Jiang(蒋刚)1,2,‡   

  1. 1 Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China;
    2 Key Laboratory of High Energy Density Physics and Technology, Ministry of Education, Chengdu 610065, China;
    3 College of Electrical Engineering, Sichuan University, Chengdu 610065, China
  • Received:2022-05-20 Revised:2022-08-02 Accepted:2022-08-26 Online:2023-04-21 Published:2023-04-21
  • Contact: Chen Yang, Gang Jiang E-mail:yangchen@scu.edu.cn;gjiang@scu.edu.cn
  • Supported by:
    Project supported by the Fundamental Research Funds for the Central Universities (Grant No. 10822041A2038).

摘要: The generation of hollow atoms will reduce the probability of light absorption and provide a high-quality diffraction image in the experiment. In this paper, we calculated the ionization rate of the Kr atom under x-ray free-electron laser (XFEL) using Hartree-Fock-Slater model and simulated the ionization model of Kr atom using Monte-Carlo method to determine the response of the hollow atom of Kr atom to the XFEL photon energy. Calculating the correlation between the total photoionization cross-section of the ground state of Kr atom and the photon energy, we determined three particular photon energies of 1.75 keV, 1.90 keV, and 14.30 keV. The dynamics simulation under the experimental condition's 17.50 keV photon energy was achieved by implementing the Monte-Carlo method and calibrating the photon flux modeling parameters. Consequently, our calculated data are more consistent with experimental phenomena than previous theoretical studies. The saturable absorption of Kr at 1.75 keV, 1.90 keV, 14.30 keV, and 17.50 keV energies was further investigated by using the optimized photon flux model theory. We compared the statistics on main ionization paths under those four specific photon energies and calculated the population changes of various Kr hollow atoms with different configurations. The results demonstrate that the population of hollow atoms produced at the critical ionization photon energy is high. Furthermore, the change of population with respect to position is smooth, which shows a significant difference between the generation mode of ions with low and high photon energies. The result is important for the study of medium- and high-Z element hollow atoms, which has substantial implications for the study of hollow atoms with medium and high charge states, as well as for the scaling of photon energy of free electron lasers.

关键词: x-ray free-electron lasers, krypton, hollow atoms, Monte-Carlo simulation

Abstract: The generation of hollow atoms will reduce the probability of light absorption and provide a high-quality diffraction image in the experiment. In this paper, we calculated the ionization rate of the Kr atom under x-ray free-electron laser (XFEL) using Hartree-Fock-Slater model and simulated the ionization model of Kr atom using Monte-Carlo method to determine the response of the hollow atom of Kr atom to the XFEL photon energy. Calculating the correlation between the total photoionization cross-section of the ground state of Kr atom and the photon energy, we determined three particular photon energies of 1.75 keV, 1.90 keV, and 14.30 keV. The dynamics simulation under the experimental condition's 17.50 keV photon energy was achieved by implementing the Monte-Carlo method and calibrating the photon flux modeling parameters. Consequently, our calculated data are more consistent with experimental phenomena than previous theoretical studies. The saturable absorption of Kr at 1.75 keV, 1.90 keV, 14.30 keV, and 17.50 keV energies was further investigated by using the optimized photon flux model theory. We compared the statistics on main ionization paths under those four specific photon energies and calculated the population changes of various Kr hollow atoms with different configurations. The results demonstrate that the population of hollow atoms produced at the critical ionization photon energy is high. Furthermore, the change of population with respect to position is smooth, which shows a significant difference between the generation mode of ions with low and high photon energies. The result is important for the study of medium- and high-Z element hollow atoms, which has substantial implications for the study of hollow atoms with medium and high charge states, as well as for the scaling of photon energy of free electron lasers.

Key words: x-ray free-electron lasers, krypton, hollow atoms, Monte-Carlo simulation

中图分类号:  (Auger effect)

  • 32.80.Hd
32.80.Aa (Inner-shell excitation and ionization)