Speaker
Description
Hot electrons generated by laser-matter interaction emit X-rays through bremsstrahlung mechanism. Precise knowledge of the energy distribution and temperature scaling of hot electrons and X-rays is crucial for exploiting laser energy in many applications such as sources of X-rays, radiography of dense plasma, photo-nuclear studies and fast ignition.
The scaling of hot electron and bremsstrahlung radiation from the interaction of sub-nanosecond and kilo-joule class laser pulse with tantalum targets was investigated. The laser intensity delivered by the PALS laser facility was varied in the range of 4×10^{15} to 3×10^{16} W. cm^{−2} at the target focus. The energy distribution functions of electrons were measured by an angular array of magnetic spectrometers indicating the electron temperature in the range of 30 to 70 keV. The bremsstrahlung spectrum was characterized using a scintillator based calorimeter. The experimental data were compared with Monte Carlo simulation showing a photon energy in the range of 10’s of keV to 100 keV. In addition, we experimentally demonstrate the laser energy scaling of the total flux of hot electrons in forward and backward directions with respect to the laser vector as well as the conversion efficiency of the laser energy to the energy carried by hot electrons.
