On the gas-solid difference in stopping power for low energy ions

摘要

In an earlier paper we claimed that the well-known gas-solid difference in high energy mass stopping powers persists down to low energy; this claim was essentially based on stopping powers for N ions. We now re-investigate this claim using many more experimental data, comparing them to the recent stopping power table of ICRU Report 73 which has no gas-solid difference built in, and by using our statistical analysis program. We find that, at a specific energy of 25 keV, the average gas-solid difference amounts to -40% for N ions and to -48% for all ions from _3Li to _(18)Ar taken together, the stopping power for gas being lower. It appears therefore that the agreement between experiment and theory could be improved by taking this difference into account.