Properties and applications of mono-energetic gamma-rays from laser-Compton scattering

Properties of a Mono-Energetic Gamma-Ray (MEGa-Ray) Compton scattering source are presented. It produces 0.1 MeV-0.9 MeV photons. Its experimental key parameters are: its size (0.01 mm$^{2})$, divergence (10x6 mrad$^{2})$, duration (ps), spectrum (15{\%} bandwidth) and intensity (10$^{5}$ photons/shot), which yield an on-axis peak brightness of $\sim $10$^{15}$ photons/mm$^{2}$/mrad$^{2}$/s/0.1{\%} bandwidth at 0.478 MeV. We detected the 0.478 MeV nuclear resonance fluorescence (NRF) line of $^{7}$Li. A LiH sample was in the beam path, and the NRF scattered photons were detected by a germanium detector oriented at 90$^{\circ}$ with respect to the incident beam axis. The resulting spectrum shows the 0.478 MeV line of $^{7}$Li, with several characteristic lines from the interaction. With this experiment, we have shown that MEGa-Ray sources will provide a unique specific isotope detection capability. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.