Author: Nilsson, A.
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Searching for the Hypothesized Liquid-Liquid Critical Point in Supercooled Water with X-Ray Free Electron Laser  
  • K.H. Kim
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  • K. Amann-Winkel
    FYSIKUM, AlbaNova, Stockholm University, Stockholm, Sweden
  • A. Nilsson
    Stockholm University, Stockholm, Sweden
  Funding: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT)(No. 2019R1C1C1006643).
Water is the most important liquid for our existence on Earth and plays an essential role in physics, chemistry, biology, and geoscience. In the liquid form, water has numerous anomalous properties as compared to other liquids such as density maximum at 4-degree C. As an explanation for these anomalous experimental observations, a hypothetical liquid-liquid transition (LLT) and a liquid-liquid critical point (LLCP) has been proposed deep in the supercooled regime. Recently a new method of rapid cooling and ultrafast probing with wide-angle X-ray scattering (WAXS) using FELs (LCLS, SACLA, and PAL-XFEL) has allowed the venture into no man’s land and we found the first experimental evidence of the existence of the Widom line which is supposed to emanate from the LLCP [1]. By introducing optical pulse to the setup, pump-probe type measurements are also possible to study the liquid-liquid transition.
[1] K. H. Kim et al., "Maxima in the Thermodynamic Response and Correlation Functions of Deeply Supercooled Water", Science, 358, 1589-1593 (2017)
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THP084 Status of the Soft X-Ray Laser (SXL) Project at MAX IV Laboratory 749
  • F. Curbis, J. Andersson, L. Isaksson, M. Kotur, F. Lindau, E. Mansten, M.A. Pop, H. Tarawneh, P.F. Tavares, S. Thorin, S. Werin
    MAX IV Laboratory, Lund University, Lund, Sweden
  • S. Bonetti, A. Nilsson
    Stockholm University, Stockholm, Sweden
  • V.A. Goryashko
    Uppsala University, Uppsala, Sweden
  • P. Johnsson, W. Qin
    Lund University, Lund, Sweden
  • M. Larsson, P.M. Salén
    FYSIKUM, AlbaNova, Stockholm University, Stockholm, Sweden
  • J.A. Sellberg
    KTH Physics, Stockholm, Sweden
  Funding: The work is supported by Knut and Alice Wallenberg foundation.
A Soft X-ray Laser project (the SXL) aiming to produce FEL radiation in the range of 1 to 5 nm is currently in a conceptual design phase and a report on the design is expected to be delivered by March 2021. The FEL will be driven by the existing 3 GeV linac at MAX IV laboratory, which also serves as injector for the two storage rings. The science case has been pushed by a large group of mainly Swedish users and consists of experiments ranging from AMO physics to condensed matter, chemistry and imaging in life science. In this contribution, we will present the current conceptual design of the accelerator and the FEL operation modes together with a general overview of the beamline and experimental station. In particular design options for the FEL will be discussed in conjunction with the features of the electron beam from the MAX IV linac and the connection with the proposed experiments.
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About • paper received ※ 21 August 2019       paper accepted ※ 28 August 2019       issue date ※ 05 November 2019  
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