R. N. Gosselin

Beam-Foil Lifetime Measurements Using ANDC Analysis for the Resonance Doublet in Ar VIII, Kr VIII and Xe VIII

Some practical methods are suggested for applying the Arbitrarily Normalized Decay Curve (ANDC) method for cascade-correction in beam-foil lifetime measurements. These methods are used to analyze decay curves recorded for the ns2S-np2P0 resonance doublet in Ar VIII, Kr VIII and Xe VIII by including the np2P0-nd2D cascade transitions in the analysis. The f-values derived from the np lifetimes for the ns-sp multiplet are in good agreement with recent theoretical estimates for Ar VIII and Kr VIII and agree with theory for Xe VIII within the combined experimental and theoretical uncertainties.

Energy-level and lifetime measurements for Sb IV and Sb V

A study of the beam-foil spectrum produced by a 1-MeV beam of antimony ions has yielded lifetimes for nine lowlying terms of Sb iv and six of Sb v. Decay-curve analysis incorporating the andc method to correct for cascade effects has given lifetimes for the upper state involved in the resonance transitions of both ions that are in reasonable agreement with most recent calculations. New energy-level assignments are given for the 5s5d1D2, 5s6d1D2, and 5s4f1F3 levels of Sb iv and for the 6d2D3/2,5/2 and 4f2F5/2,7/2 levels of Sb v.

A study of the beam-foil spectrum of Xe V

Beam-foil spectra have been searched for transitions in Xe V suggested by comparison with the structure of I IV and Cs VI, and by an MCHF calculation. Twenty-nine lines are assigned to transitions between 22 levels of the 5s25p2 and the 5s5p3, 5p5d and 5p6s configurations. Lifetime measurements for 24 of these lines are used in support of the new assignments.

Precision lifetime measurement of the z4D°52 level ofTi+ using laser excitation of a fast ion beam

Abstract An excimer laser has been used to populate the z 4 D° 5 2 level of Ti + ions in a fast beam. The observed decay of fluorescence intensity gives a lifetime of 4.01 ns with a one standard deviation uncertainty of ±0.06 ns.

Energy level and lifetime measurements for Ar VI

Assignments are suggested for 32 transitions in Ar VI involving doublet levels in the 3p3 and 3s3p3d configurations. Beam-foil decay curves are used to measure the lifetimes of these levels, the results being systematically about 25% longer than the values calculated by Fawcett. These decays are also used in ANDC analyses of the lifetimes of the 3s3p2 2S, 2P, 2D and 3s23d2D levels, where the agreement with Fawcetts calculation is generally good. A discussion is also given of the alternative analysis of the Ar VI spectrum recently published by Lesteven-Vaisse et al. using recoil-ion techniques.

Precision lifetime measurements of levels of Ti+, Ca+ and Na+ using laser excitation of a fast ion beam

Abstract We have obtained cascade-free lifetimes for the 3 d 2 4 p z 4 D 5 2 o level in Ti+ (4.01±0.06 ns0, the 4 p 2 P 1 2 o , 3 2 , levels in Ca+ (6.95 ± 0.18 ns and 6.87 ± 0.17 ns respectively) and the 2 p 5 ( 2 P o 3 2 )3 p [ 5 2 ] J = 3 level in Na+(4 technique. These experiments demonstrate some possible variations of the beam-laser method. These results are compared with previous experiments and theory.

Lifetimes of the 3s 2S and 2s2p22S, 2P, 2D terms of N III

Abstract ANDC analyses of beam-foil data are used to obtain lifetimes for four low-lying even doublet terms of doubly ionized nitrogen. The effects of cascading on the measured lifetimes are found to be relatively minor.