Effect of Compton scattering on the double to single ionization ratio in helium

摘要

The ratio of double to single ionization in Helium produced by photon impact has been measured for photon energies from 2.1 to 5.5 keV. The measurements suggest that a significant contribution to the single ionization cross section is caused by Compton scattering for energies greater than (approximately) 3.8 keV. After accounting for the ionizing Compton scattering the measured ratio is not inconsistent with recent calculations of the asymptotic limit of the ionization ratio caused by photoabsorption which predict a limit near 1.66%.