Outer s-shell ionization of neon, argon, and krypton by proton impact (125 keV-1200 keV)

The ionization of the neon 2s-, argon 3s-, and krypton 4s-shell has been studied by proton impact in the energy range 125 keV to 1200 keV. Total cross sections have been obtained by measuring light intensities resulting from the decay of the excited ions; the corresponding wavelengths lie in the vacuum ultraviolet region. The cross sections have been made absolute by comparing the signal rates resulting from 1 keV electron impact and 400 keV proton impact and using the known electron impact cross sections. The results are compared with electron impact data and with theoretical data.