Enhancing Bremsstrahlung Production From Ultraintense Laser-Solid Interactions With Front Surface Structures

We report the results of a combined study of particle-in-cell and Monte Carlo modeling that investigates the production of Bremsstrahlung radiation produced when an ultraintense laser interacts with a tower-structured target. These targets are found to significantly narrow the electron angular distribution as well as produce significantly higher energies. These features combine to create a significant enhancement in directionality and energy of the Bremstrahlung radiation produced by a high-Z converter target. These studies employ short-pulse, high intensity laser pulses, and indicate that novel target design has potential to greatly enhance the yield and narrow the directionality of high energy electrons and $\gamma$-rays. We find that the peak $\gamma$-ray brightness for this source is 6.0$\times$10${}^{19}$ ${\rm s^{-1}mm^{-2}mrad^{-2}}$at10MeVand1.4$\times$10$^{19}$ ${\rm s^{-1}mm^{-2}mrad^{-2}}$at100MeV(0.1$%$ bandwidth).