Speaker
Mianzhen Mo
(University of Alberta)
Description
Study of the ionization state of material in the warm dense matter regime is a significant challenge at present. Recently, we have demonstrated that the femtosecond duration Betatron x-ray radiation from the laser wakefield acceleration of electrons is capable of being employed as a probe to directly measure the ionization states of warm dense aluminum via K-shell line absorption spectroscopy [1]. In order to apply the radiation for such an application, a Kirkpatrick-Baez Microscope is used to selectively focus the radiation around the 1.5 keV photon energy range onto a 50-nm free-standing aluminum foil that is heated by a synchronized 800 nm laser pump pulse. The transmitted x-ray spectrum is spectrally resolved by a flat Potassium Acid Phthalate (KAP) Bragg crystal spectrometer. Here we report the results of the first-time direct measurements of the ionization states of warm dense aluminum using this Betatron x-ray probe setup. Measurements of the ionization states were taken at two pump fluences and various time delays to observe the evolution of the warm dense matter state. Plasmas spectroscopic modeling associated with 1D hydrodynamic simulation is being carried out to interpret the ionized charge distributions from the measured K-shell absorption lines. Details of the measurements and simulations will be presented.
[1] M.Z. Mo, et al., Rev. Sci. Instrum. 84, 123106 (2013).
Author
Mianzhen Mo
(University of Alberta)
Co-authors
Prof.
Andrew Ng
(University of British Columbia)
Mr
Arpit Saraf
(INRS-EMT)
Prof.
Jean-claude Kieffer
(INRS-EMT)
Mr
Raj Masud
(University of Alberta)
Robert Fedosejevs
(University of Alberta)
Mr
Shaun Kerr
(University of Alberta)
Dr
Sylvain Fourmaux
(INRS-EMT)
Prof.
Ying-yin Tsui
(University of Alberta)
Dr
Zhijiang Chen
(SLAC)
