KK electron capture cross sections for 0.4 to 1.5 MeV 11H + and 1.0 to 2.0 MeV 24He + projectiles incident on gaseous CH 4 targets

Abstract

The ratio of the cross section for KK electron capture to the total K-vacancy production cross section is measured by an electron-ion time-of-flight coincidence technique for 0.4 to 1.5 MeV 1 1H + and 1.0 to 2.0 MeV 2 4He + projectiles under single collision conditions with gaseous CH 4 targets. Electron capture cross sections were determined by multiplying the measured ratios by the total K-vacancy production cross sections which were measured in a separate experiment. In that experiment the integrated yield per incident projectile in the Auger-electron-peak for 0.6 MeV 1 1H + projectiles was normalized to 9.54 × 10 −19 cm 2, the absolute cross section of Stolterfoht and Schneider [23]. The total K-vacancy production cross sections on this absolute scale were used to extract the electron capture cross sections reported here.