Modeling of brightness temperature under intense heavy ion beam loading of target

HIHEX experiments at GSI-Darmstadt are carried out for investigation of material properties and processes in matter under intense heavy ion beam loading. In these experiments [1, 2], a heavy ion beam of U with an initiation energy of 350AMeV was used to irradiate a lead foil with a thickness of 250 μm. The temperature of the expanded part of the foil was measured by a pyrometer through the transparent window all of sapphire in direction normal to the foil surface. The measurements were made at several wave lengths (0.65, 0.75 and 0.95 μm). Numerical modeling [3] gives us detailed information about evolution of the temperature, density, pressure and velocity of target material as a result of beam heating. It is shown that the expanded matter was in a two-phase liquidvapor state. As noted by Zeldovich [4], the pyrometry technique measures radiation temperature in the expanded metal not from the surface but from a more deep layer. In order to compare the temperature profile from ion-beam driven experiment and the temperature from numerical modeling, it is necessary to calculate light emission from the depth of material in the same conditions as in the experiment. This model has been used to construct an intensity profile from the 2D simulation results (density, temperature) for a comparison with the profiles measured in the experiments.