Origins and Reduction of Line Broadening in the Spectra of Fast Ion Beams

Abstract

Several factors associated with the high linear velocity of the emitters contribute to linewidths in the spectra of fast ion beams . These include broadening associated with the acceptance angles determined by the spectrometer's collimator and slit, diffraction at the entrance slit, decollimation due to scattering and external fields, and the limited time during which an ion can emit into the spectrometer . We discuss the observations of the known effects and those likely to appear, and consider methods for reducing them .

Beam–foil spectroscopy—Quo vadis?

“…Straightforward spectroscopy of foil-excited ion beams suffers from the excitation of too many lines that can make identification difficult in the absence of high quality calculations. However, this drawback and the often considerable line width (unless refocusing techniques are employed [228][229][230][231][232]) are offset by the fact that the BFS light source is monoisotopic: with the exception of some few carbon UV lines (from the foil, possibly after sputtering), all the light is that of a defined element, and even the charge state can be determined within a few units by suitable beam energy variation. The accumulation of a 'complete' spectral data base of all elements and from the x-ray range to the visible or even to the near infrared would be of great scientific and applied science value, but, alas, it would also be prohibitively expensive in terms of accelerator time and manpower.…”

Untitled

“…se; this typically is a few angstroms in the visible region. Some measurements have been Stoner & Leavitt (1971Leavitt ( ,1973, and Bergkvist (1976) in a more general treatment, showed how to greatly reduce the line broadening using refocussing techniques. Resolutions, 8A!…”