CHARGE STATE FLUCTUATIONS AND ENERGY-LOSS STRAGGLING OF FAST IONS IN COLD AND IN PLASMA TARGETS

The energy loss and straggling of fast ions in solid and plasma targets were calculated. In particular, the role of charge state fluctuations in determining the straggling profiles was investigated. It is found that in foil targets charge state fluctuations can drastically increase the width of the energy spectrum upon exit. In plasma targets they can drastically smear the ideally sharp Bragg peak in the energy deposition profile. A comparison of the results of calculations for beam-foil interaction with an experiment which is briefly described is made.