Slowing down of relativistic few-electron heavy ions

Abstract

Experimental data on energy loss and energy-loss straggling of fully ionized relativistic heavy ions agree well with the theory of Lindhard and Sørensen (LS). However, when heavy ions penetrate matter with many fluctuating ionic charge states the theoretical description is more complicate and less accurate. A novel exploratory step to contribute to a better understanding of the slowing down of heavy ions has been done with the present experiment in an energy region where the atomic interaction is still dominated by bare and few-electron projectiles. In the energy range of 100–1000 MeV/u we measured with the high-resolution magnetic spectrometer FRS the stopping powers, the energy-loss straggling and the charge-state distributions of 197Au, 208Pb and 209Bi projectiles in charge-state equilibrium interacting with solids ranging from beryllium to lead targets. Additionally, charge exchange cross-sections have been measured to support a better analysis and interpretation of the energy-loss data. The experimental results on stopping power and energy-loss straggling clearly demonstrate the contribution of ions in different charge states. A novel application of the slowing down of relativistic exotic heavy ions is presented.