Some experimental results on W values for heavy particles

Abstract
The total ionization produced by ions stopped in argon and tissue-equivalent (TE) gas has been measured in the energy range 25-500 keV. A large ionization chamber was used. The chamber was alternately operated as a proportional counter and as an ionization chamber to measure particle rate and the total ionization produced by them, respectively. The average energy loss per ion pair (W value) was found to be dependent on both the energy and mass of the incident ions. For argon gas the accelerated ions were He+, He+, Ar+. For TE gas the accelerated ions were H+, He+, C+, N+, O+.