PHOTO-IONIZATION OF KRYPTON BETWEEN 300 AND 15OO EV - RELATIVE SUBSHELL CROSS SECTIONS AND ANGULAR DISTRIBUTIONS OF PHOTOELECTRONS

Energy spectra of electrons ejected from M and N subshells of krypton by characteristic x rays of 300 to 1500 eV energy have been measured with an electrostatic analyzer. Krypton was irradiated in the gas phase and electrons were detected perpendicular to the x-ray beam. From these spectra, relative subshell contributions to the photo-ionization cross section were obtained for single-electron emission and for double-electron emission, the latter involving simultaneous transitions of M and N electrons. Angular distributions of photoelectrons from 3s, 3p and 3d shells of krypton and 1s shell of neon also have been determined at excitation energies from about 200 to 1100 eV above the respective ionization thresholds. Data on relative cross sections for single photo-ionization corroborate a theoretical model which uses a Herman-Skillman central potential (Cooper and Manson in the following article). Angular distributions agree satisfactorily with calculations by the same model; this means theory makes dependable predictions regarding the asymmetry parameter and the effect of retardation. Data on double photo-ionization disagree with results of the electron shakeoff theory which accounts for only about half the observed intensities. This suggests that electron-electron correlation plays an important role. © 1969 The American Physical Society.