Measuring fast electron spectra and laser absorption in relativistic laser-solid interactions using differential bremsstrahlung photon detectors

TL;DR

This paper presents a photon detector designed for measuring bremsstrahlung spectra in relativistic laser-solid interactions, utilizing Monte Carlo methods to infer electron spectra and laser absorption, demonstrated through an experiment with frequency doubled laser light.

Contribution

The paper introduces a novel photon detector and Monte Carlo analysis method for accurately measuring fast electron spectra and laser energy absorption in relativistic laser-solid experiments.

Findings

Fast electron temperature measured at 125 keV.

Effective operation of the detector demonstrated in relativistic laser experiment.

Monte Carlo analysis successfully interprets bremsstrahlung spectra.

Abstract

A photon detector suitable for the measurement of bremsstrahlung spectra generated in relativistically-intense laser-solid interactions is described. The Monte Carlo techniques used to back-out the fast electron spectrum and laser energy absorbed into fast electrons are detailed. A relativistically-intense laser-solid experiment using frequency doubled laser light is used to demonstrate the effective operation of the detector. The experimental data was interpreted using the 3-spatial-dimension Monte Carlo code MCNPX (Pelowitz 2008), and the fast electron temperature found to be 125 keV.