Measurements of electron-impact ionization cross sections of argon, krypton, and xenon by comparison with photoionization - art. no. 022723

Ratios of total cross sections for electron-impact ionization and photoioni zation in Ar, Kr, and Xe in the energy range from 140 to 4000 eV for electr ons and from 16 to 1012 eV for photons were measured. Comparatively low rel ative standard uncertainties of 1.3-1.9 % were achieved using an apparatus combining two recent instrumental developments. The first is associated wit h a highly accurate device for the determination of soft-x-ray and vacuum-U V photon Bur, a cryogenic electrical substitution radiometer. The second is an upgraded ionization chamber for the precise comparison of total-ion yie lds for electron and photon impact. On the basis of our measured cross-sect ion ratios and well-known total photoionization cross-section data, we dedu ced absolute total electron-impact ionization cross sections of the rare ga ses with relative standard uncertainties as low as 2%.