Selective photo-activation analysis with laser-driven x-rays

We discuss a technique for the identification of nuclear isotopes by \textit{selective} photo-activation analysis. A narrow divergence beam of high-energy photons is produced when a laser driven electron beam Compton backscatters off a counter-propagating high-intensity laser pulse. The x-rays from this compact laser-driven synchrotron light source are MeV energy, narrow-bandwidth, tunable, polarized, and bright (10$^{\mathrm{8}}$ photons s$^{\mathrm{-1}})$. Such characteristics make these x-rays well-suited for nuclear interrogation by means of triggering ($\gamma $,f) and ($\gamma $,xn) reactions. The narrow bandwidth of the x-ray light can be exploited to selectively activate nuclei with isotopic sensitivity, without causing unwanted background from collateral activation. Additionally, the polarized nature of the x-rays can be used to study anisotropy of neutron emission, for precise identification of isotopes. Activation by laser-driven synchrotron x-rays will be compared with activation by bremsstrahlung.