Generation of MeV photons with kJ multi-ps laser pulses*

Studying high energy density (HED) matter is expanding our understanding of inertial confinement fusion, astrophysical systems, planetary interiors and fundamental plasma physics. Laser produced x-rays are key tools in this exploration due to their ability to passively probe/radiograph such matter. To radiograph high areal density objects, broad band x-ray sources require a large flux (10\textasciicircum 13-10\textasciicircum 14 photons/steradian/MeV) of \textgreater 2 MeV photons. In this work we generate a high yield x-ray source through bremsstrahlung by irradiating a high-Z target with kJ, ps laser pulses. We control the laser to target coupling by changing the plasma scale length, the laser intensity and by using a range of advanced targets, such as compound parabolic concentrator plasma optics to increase the laser intensity for large F/{\#} laser systems. Modeling suggests that these targets can increase the laser intensity by as much as 100x making them very attractive for high F/{\#} systems such as NIF ARC and PETAL at LMJ.