Lifetimes of Heavy Ions Using Beam-Foil Spectroscopy in the 100 TO 300 KEV Energy Range.
Abstract
The methods of Beam-Foil Spectroscopy (BFS) have been extended and applied to the measurement of atomic lifetimes of near-neutral, very heavy ions. Selected for measurement were various levels of alkali-like and inert gas-like (or noble-like) ions that have important astrophysical and theoretical implications. These ions include Ne I, Y III, Au II, Hg II and Hg III. The lifetimes were obtained from intensity decay curves via multiexponential (ME) curve fitting and joint analysis using the Arbitrarily Normalized Decay Curve (ANDC) method. In addition to the many measurements (Y III, Au II, and Hg III) made for the first time, various re-measurements (Ne I and Hg II) have also been performed in order to obtain higher precision measurements of these levels of exceptional theoretical importance. The low energies required to produce appreciable quantities of these near-neutral ions, together with effects due to the ions' high nuclear charge combine to create additional experimental challenges, such as premature foil failure and postfoil beam divergence. These problems and some of the solutions to these problems are discussed in some detail.
- Publication:
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Ph.D. Thesis
- Pub Date:
- 1993
- Bibcode:
- 1993PhDT.......194M
- Keywords:
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- Physics: Atomic