B.M. Johnson

Calculated K Auger-electron and K X-ray transition energies for the multiply ionized neon atom☆

Abstract Presented here are the energies of all of the possible Auger-electron and X-ray transitions from particular states (described by LS coupling) in Ne 1+ to Ne 7+ and Ne 8+ . The values, calculated with Hartree-Fock wavefunctions, are compared with recent measured values for highly ionized neon produced by energetic heavy-ion bombardment. Comparison is also made with conventional electron bombardment data.

A general description of K X-ray de-excitation of titanium☆

Abstract Measurements of Kα and Kβ X-rays induced by proton, alpha and oxygen particle beams from an electrostatic accelerator show a divergence from the normal X-ray spectrum as the nuclear charge of the incident beam increases. The results of these measurements are consistent with the explanation that the ion excitation produces multiple inner-shell electron vacancies, which in turn causes electronic-shell energy shifts.

Measured K-shell fluorescence yields for multiply-ionized neon☆

Abstract The Ne K-shell fluorescence yields ω i have been measured for single K-shell and i th degree L-shell ionization. For O 5+ bombardment ω i × 100 = 1.8, 1.9, 2.2, 3.1, 5.4, 9.9, and 16.1 for i = 0 to 6, respectively. For the higher charge states ω i is measured to be up to 2 times larger than the theoretical prediction.

Metastable X-ray emission following violent Cl13+–Ne collisions

Abstract For Cl 13+ bombardment the K X-ray transition from the metastable 4 P state in Li-Like Ne is clearly resolved from an overlapping Be-like line. Previously measured K-shell fluorescence yields are corrected for this overlap. The detected rate of metastable to prompt X-ray emission from Li-like Ne is observed to vary with projectile energy.

High-resolution Ne K Auger-electron spectrum produced by 45 MeV Cl12+ ion impact

A Li and Be-like Ne K Auger-electron spectrum produced by 45 MeV Cl12+ ion impact on neon with a spectroscopic resolution of 1.5 eV (FWHM) is reported. The spectral features are compared to the competing high-resolution Ne K X-ray spectrum in order to identify the spectral structure and to determine the fluorescence yield for the initial Li-like (1s2s2p) configuration in neon.

Observation of a projectile charge dependence for the neon K-auger electron spectrum

Oxygen (plus six) and (plus eight) at 30 MeV incident energy have been used to induce Auger electron spectra of Ne. The high instrumental resolution (0.02% FWHM) spectra show specifically that the charge state of the incident oxygen ion considerably affects the distribution of the K-Auger electron yield among the charge states of multiply ionized neon.

A high resolution study of Ar LMM Auger electrons produced by ion bombardment

Ar LMM Auger electron lines produced by H+, He+, O4+, and O5+ bombardment are measured with high instrumental resolution (0.02% FWHM). Individual heavy ion induced Auger satellite lines are resolved. Two strong lines are observed at 221 and 223 eV in the oxygen induced spectra. The ratio of satellite to normal line production is given for each projectile.

High resolution Ar-LMM and Kr-MNN Auger electron spectra produced in collisions with heavy ions at MeV energies

Abstract High resolution Ar-LMM and Kr-MNN Auger spectra produced by oxygen and chlorine ions incident on argon and krypton at several MeV are reported and compared to spectra from lighter ion impact. The increase of the probability from light to heavy ion impact for MNn multiple ionization in Kr is found to be comparable lower than for the MNn multiple ionization in Ar. The heavy ion induced spectra show in both cases a satellite line structure, which is assumed to result from initial states consisting of highly ionized outer shells and additional electrons being excited into high bound levels.

Auger electron emission spectra from foil and gas excited carbon beams

Auger electron emission spectra from 2 MeV C+ ions excited by collisions with thin carbon foils and Ne gas are presented. The similarity of qualitative features for the C+ → C (foil) and C+ → Ne spectra indicates the similarity of ionization mechanisms for beam foil and beam gas excitation. The spectra were normalized to the lowest lying Li-like quartet state (1s 2s 2p) 4po in carbon by comparison with time delayed foil excited electron decay-in-flight spectra. Comparison to Hartree Fock calculated transition energies indicates that transitions in three and four electron carbon ions dominate the prompt spectra.

ALPHA- AND PROTON-INDUCED X-RAY DEEXCITATION OF TITANIUM.

Measurements of Kα and Kβ x rays induced by proton and α‐particle beams from an electrostatic accelerator show a divergence from the normal x‐ray spectra as the nuclear charge increases. These measurements are consistent with the explanation that the ion excitation produces multiple inner‐shell electron vacancies, which in turn cause electronic‐shell energy shifts. The intensity of these shifted lines is a measure of the amount of multiple inner‐shell ionization.