Radiation dynamics of fast heavy ions interacting with matter (vol 23, pg 79, 2005)

The study of heavy ion stopping dynamics using associated K-shell projectile and target radiation was the focus of the reported experiments. AT, Ca, Ti, and Ni projectile ions with the initial energies of 5.9 and 11.4 MeV/u were slowed down in quartz and arogels. Characteristic radiation of projectiles and target atoms induced in close collisions was registered. The variation of the projectile ion line Doppler shift due to the ion deceleration measured along the ion beam trajectory was used to determine the ion velocity dynamics. The dependence of the ion velocity on the trajectory coordinate was measured over 70-90% of the ion beam path with a spatial resolution of 50-70 mu m. The choice Of SiO2 aerogel with low mean densities of 0.04-0.15 g/cm(3) as a target material, made it possible to stretch the ion stopping range by more than 20-50 times in comparison with solid quartz. It allowed for resolving the dynamics of the ion stopping process. Experimentally, it has been proven that the fine porous nano-structure of aerogels does not affect the ion energy loss and charge state distribution. The strong increase of the ion stopping range in aerogels made it possible to resolve fast ion radiation dynamics. The analysis of the projectile K alpha-satellites structure allows supposing that ions propagate in solid in highly exicted states. This can provide an experimental explanation for so called gas-solid effect.