Test of various theories forK-shell ionization by protons

Abstract

Several theories for inner-shell ionization are tested by comparison with our recently published empirical reference cross-sections. The ECPSSR theory describes the data well except at low velocity where it becomes too high by as much as a factor 5. The recent RPWBA-BC calculation by Chen and Crasemann is excellent at intermediate velocity but only slightly better than ECPSSR at low velocity, since it uses the same Coulomb correction as ECPSSR, and even though it employs better wave functions. The recent SCA calculation by Hansteen et al. is the only one that describes the data within a few percent down to the lowest velocities available. The calculations by Ford et al. for Al are about 25% low. The comparatively simple formula by Montenegro and Sigaud describes the data about as well as ECPSSR, except at high velocities. Calculations by Aashamar, by Manson and by Ford et al. for Ne are about 10–20% low, but not far outside our estimated error. Our cross-sections agree well with the recent empirical fit due to Rosato but less with the fits due to Johansson et al. and Khan et al.