A compact electron spectrometer for hot electron measurement in pulsed laser solid interaction

Ultraintense laser-matter interactions provide a unique source of temporally short, broad spectrum electrons, which may be utilized in many varied applications. One such, which we are pursuing, is as part of a diagnostic to trace magnetic field lines in a magnetically confined fusion device. An essential aspect of this scheme is to have a detailed characterization of the electron angular and energy distribution. To this effect we designed and constructed a compact electron spectrometer that uses permanent magnets for electron energy dispersion and over 100 scintillating fibers coupled to a 1024×1024 pixel charge coupled device as the detection system. This spectrometer has electron energy coverage from 10 keV to 60 MeV. We tested the spectrometer on a high intensity (1017–1021 W/cm2) short pulse (<100 fs) laser, JanUSP, at Lawrence Livermore National Laboratory using various solid targets. The details of the spectrometer and the experimental results will be reported.