MONTE-CARLO SIMULATION OF MARTIAN GAMMA-RAY SPECTRA INDUCED BY GALACTIC COSMIC-RAYS

The HERMES code system containing the latest state-of-the-art particle transport codes is applied to simulate galactic-cosmic-ray-irradiated planetary surfaces, calculating their neutron and gamma-ray emission spectrum by Monte Carlo techniques. Experimental data from Apollo missions are compared to calculations for the lunar surface in order to show the validity of the new calculational procedure. The agreement is found to be excellent, so simulations of the martian surface are expected to give reliable results. Possible methods to determine the water concentration of a homogeneous martian soil from neutron and gamma-ray emission spectra are shown. The calculational procedure is discussed and compared to previous works.