ENERGY-LOSS OF FAST CLUSTERS THROUGH MATTER

Energy loss in the MeV range of simple clusters impinging on thin carb on targets has been measured using a time-of-flight method. Stopping-p ower ratios defined as the ratio of the stopping power of the cluster to the sum of the stopping powers of the constituent atoms moving at t he same velocity were investigated, Stopping-power ratios close to uni ty were observed for O-2 and B-3 clusters, while deenhancement effect is observed in the stopping-power ratios of C-3 and C-4. The experimen tal results are compared both with an existing theoretical model, whic h takes into account the spatial correlation of the fragments, and wit h a simple united-atom model, which also includes the charge state evo lution of the fragment ions inside the target. [S1050-2947(97)10711-9] .