Extreme ultraviolet beam-foil spectroscopy of highly ionized neon and argon

Typescript (photocopy).A study of the extreme ultaviolet radiation emitted by ion beams of highly ionized neon and argon after passage through thin foils was conducted at the variable energy cyclotron at Texas A&M University. A grazing incidence spectrometer was equipped with a position sensitive microchannel plate (MCP) detector which improved the detection efficiency by two orders of magnitude. The position information of the MCP was determined to be linear over 90% of the 50 mm wide detector. Spectra spanning regions of over 100 Å were accumulated at a resolution of less than 1 Å. A wavelength calibration based on a second order equation of spectrometer position was found to result in an accuracy of ± 0.1 Å. Over 40 transitions of Ne VIII, Ne IX, and Ne X were observed in the wavelength region from 350 to 30 A from n-2-3,4,5; n-3-4,5,6,7,8; n-4-6,7; and n=-5-9. An intensity calibration of the detection system allowed the determination of the relative populations of n=3 states of Ne VIII and Ne IX. An overpopulation of states with low orbital angular momenta support electron capture predictions by the first order Born approximation. The argon beam-foil data confirmed the wavelength predictions of 30 previously unobserved transitions in the wavelength region from 355 to 25 Å from n-2-2; n-3-4; n-4-5,6,7; n-5-6,7; and n-6-8. Lifetime determinations were made by the simultaneous measurement of 26 argon lines in the spectral region from 295-180 Å. Many of the n-2-2 transitions agreed well with theory