Bremsstrahlung emission and plasma characterization driven by moderately relativistic laser–plasma interactions

Abstract

Relativistic electrons generated by the interaction of petawatt-class short laser pulses with solid targets can be used to generate bright x-rays via bremsstrahlung. The efficiency of laser energy transfer into these electrons depends on multiple parameters including the focused intensity and pre-plasma level. This paper reports experimental results from the interaction of a high intensity petawatt-class glass laser pulses with solid targets at a maximum intensity of 1019 W cm−2. In-situ measurements of specularly reflected light are used to provide an upper bound of laser absorption and to characterize focused laser intensity, the pre-plasma level and the generation mechanism of second harmonic light. The measured spectrum of electrons and bremsstrahlung radiation provide information about the efficiency of laser energy transfer.

Optimization and control of synchrotron emission in ultraintense laser–solid interactions using machine learning

“…Irradiation of a solid target with a relativistically intense laser pulse typically produces a large number of photons with energies extending to the multi-MeV range, due to bremsstrahlung radiation from laser-accelerated electrons propagating through the target [1][2][3] and X-ray line emission from excited atomic states [4] . These bright sources of X-rays and gamma rays have potential applications including radiography [5][6][7][8] , initiating photonuclear reactions [1,9] and producing beams of positrons through the Bethe-Heitler process [10][11][12][13][14] .…”

Instruments for best target position determination in the high-intensity laser-solid interaction experiment

“…We have installed several NIR-vis-UV diagnostics 17,18 for observation of the reflected beam footprint in the 'specular reflection' direction in the 200 -1000 nm spectral range, as relativistic plasma surfaces act as efficient generators of loworder harmonics 19 . A PTFE (Teflon) screen was mounted perpendicularly to the direction of the reflected beam.…”

Online measurements of gamma radiation from laser-plasma and signal unfolding using a scintillator calorimeter

“…Detectors based on scintillators arranged in a stack and coupled with optical readout seem to offer a novel approach to measuring such Bremsstrahlung radiation, as was demonstrated in the literature [15][16][17] . Scintillating materials emit visible light, detectable by a standard CMOS or CCD camera, when exposed to the ionizing radiation.…”