Doppler-shifted reflections of χ rays in beam foil spectroscopy: comments George S. Bakken

Life Sciences Department, Indiana State University, Terre Haute, Indiana 47809. Received 12 August 1976. Recently, Bernstein and Mclntyre1 reported observations

on satellite spectra resulting from Doppler-shifted light re­flected from the exciting foil during a beam foil spectroscopy experiment, and claimed "the first detailed investigation and confirmation of the origin of the satellites." Although their mention of reports in the 2000-3000-Å region2,3 clearly indi­cated that their claim is intended to be for Doppler-shifted foil-reflected spectra in general, this claim is true only for the vacuum ultraviolet and x-ray regions.

Bakken et al.4 observed Doppler-shifted foil-reflected lines in 1969. The origin of the satellite lines was confirmed by changing the energy of the incident carbon ion beam, which Doppler-shifted both direct and reflected lines; by comparison of the intensity ratios (5:3:1) of the direct and reflected lines with the known C III triplet at 4647.4 A, 4650.2 A, and 4651.5 Å (Ref. 5); as well as by the second-order (relativistic) Doppler shift of the average wavelength of the direct and reflected lines relative to the known triplet. The foil-reflected lines were used to correct for the large Doppler shift inherent in the end-on collimating system used.

References 1. E. M. Bernstein and L. C. Mclntyre, Jr., Appl. Opt. 15, 1899

(1976). 2. H. G. Berry, J. Desquelles, and M. Dufay. Phys. Rev. A 6, 600

(1972). 3. J. O. Stoner, Jr., and I. Martinson, in Proceedings of the 4th In­

ternational Conference on Beam-Foil Spectroscopy, Gatlinburg, Tenn., September, 1975 (Plenum, New York, 1976), p. 259.

4. G. S. Bakken, A. C. Conrad, and J. A. Jordan, Jr., J. Phys. B 2, 1378 (1969).

5. K. Bockasten. Ark. Fys. 9, 457 (1955).

December 1976 / Vol. 15, No. 12 / APPLIED OPTICS 2967