Many applications of laser matter interaction at relativistic intensities, for e.g., ion acceleration, fast ignition, X-ray and neutron radiography, depend crucially on the laser absorption into hot electrons. Measurement of bremsstrahlung spectra generated by these hot electrons inside the target provides information on the electron energy distribution and their transport inside the target.
In this poster, we present results from a recently conducted experimental campaign using the 9 th beam of the SG-II Upgrade laser facility in Shanghai Institute of Optics and Fine Mechanics (SIOM). The p-polarized laser delivered approximately 300 J on target with a pulse duration of about 1 ps and focused intensity of about 7x10 18 W/cm 2 . Tantalum targets of various thickness from 100 um to 3 mm were shot during the experiment. Bremsstrahlung emission was measured using scintillator stack detectors  and forward Compton scattering high energy X-ray spectrometer . In situ measurement of reflected laser energy in the specular direction was done using a scattering plate. The measurements characterize laser absorption into hot electrons, and the subsequent generation of high energy X-rays.
. D. R. Rusby et al., Rev. Sci. Inst. 89, 073502 (2018)
. S. Singh et al., Rev. Sci. Inst. 89, 085118 (2018)
|Working group||Secondary radiation generation & applications|