T. M. Kavanagh

Direct observation of multiple L-shell vacancy effects in energetic heavy ion collisions☆

Abstract Observations have been made of soft L X-ray spectra resulting from collisions of 8–20 MeV oxygen ions and Ni, Cu and Zn atoms. These observations provide confirmation of the multiple L-shell vacancies proposed to explain recent experimental determinations of K-shell X-ray energy shifts in such collisions. The energy dependence of the single vacancy shifts indicate that the probability of outer shell ionization is a decreasing function of ion energy in this energy range.

A Small Bragg Diffraction X‐Ray Spectrometer

A small, easily constructed, and high efficiency Bragg angle x‐ray spectrometer has been developed. Employing either a lead stearate or a KAP crystal, it has been used to measure x rays in the 150–1000 eV region from ion‐atom collisions. At the carbon‐K energy (277 eV), it has an FWHM of 14 eV and an efficiency of 10−2 counts per incident x ray. Electronics and controls for fully automatic scans are described.

Variation of copper L shell fluorescence yield in ion-atom collisions

Changes in the fluorescence yield of the copper L shell due to multiple M shell ionization are considered. The results are found to be very different to previously published results on the argon L shell. In particular the copper L shell fluorescence yield is essentially constant (varies less than 10%) for as many as six M shell vacancies. Reasons for the different characteristics of argon and copper are discussed.

The proton-reduced L X-ray spectrum of argon☆

Abstract The argon L X-ray spectrum produced by 100 keV protons is presented. A new line, not observed in the electron- produced spectrum, appears at 262 eV is interpreted as a 3d→2p transition. Since the 3d level is normally empty in argon, the data provide the first direct evidence from X-rays following proton bombardment of excitation of electrons to bound states.

Xenon m X-ray spectra from ion-atom collisions

Abstract Soft X-ray spectra from collisions involving 180 keV Xe ++ ions and Cr, Mn, Fe, Co, Ni, Cu and Xe targets are presented. Promotion of electrons into the normally vacant 4f level of Xe is observed and this promotion is found to be a strong function of the Z of the target.

X-rays from ion-atom collisions in solid targets

Abstract X-ray spectra from 100 keV Ne + bombardment of solid copper targets are presented. Copper L X-rays are more intense than neon K X-rays, in disagreement with simple systematics for diabatic molecular orbitals. The data can be explained by the increase of the neon 1s binding energy caused by outer-shell stripping.