Diagnostics of quasi mono-energetic photon sources in a single shot using CCD trackers

Abstract

Laser plasma accelerators generate GeV electrons within centimeters. MeV-level mono-energetic photon sources can be produced by scattering laser photons off the GeV electrons. The MeV mono-energetic photon sources can be used in radiography, photo-fission and nuclear resonance fluorescence to detect special nuclear materials for nonproliferation purposes. A diagnostic system is needed to characterize the energy and angular deviations of the photons. We propose a diagnostic scheme of using a thin scatter foil to induce Compton electrons. The electrons produce tracks when being captured by the scientific CCDs. The energies and directions of the electrons estimated from the tracks are used to compute the energies and positions of the incoming photon sources. Diagnostics of a nominal source and four variations are simulated in GEANT4. Quadratic classifiers achieve a mean accuracy of 86% when discriminating sources of 7 × 108 photons with different angular spreads.