Femtosecond soft X-ray absorption spectroscopy of warm dense matter at the PAL-XFEL

Free-electron laser pulse-based X-ray absorption spectroscopy measurements on warm dense copper are presented. The incident X-ray pulse energies were measured with a detector assembly consisting of a photocathode membrane and   microchannel plates, and the transmitted energies were measured simultaneously with a photodiode detector. The precision of the absorption measurements was evaluated. For a warm dense copper foil irradiated by an intense femtosecond laser pulse, the enhanced X-ray absorption below the L3-edge, followed by the rapid evolution of highly excited Fermi liquid within a   picosecond, were successfully measured. This result demonstrates a unique capability to study femtosecond non-equilibrium electron – hole dynamics in extreme states of matter.

Source: Journal of Synchrotron Radiation - May 18, 2020 Category: Physics Authors: Lee, J.-W. Kang, G. Kim, M. Kim, M. Park, S.H. Kwon, S. Yang, S. Cho, B.I. Tags: X-ray free electron lasers X-ray absorption spectroscopy warm dense matter research papers Source Type: research