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Title: Lifetime of the 1s2s 3S1 metastable level in He-like S14+ measured with an electron beam ion trap

Abstract

A precision measurement of the lifetime of the lowest exited level of the He-like S{sup 14+} ion carried out at the Livermore EBIT-II electron beam ion trap yielded a value of (703 {+-} 4) ns. Our method extends the range of lifetime measurements accessible with electron beam ion traps into the nanosecond region and improves the accuracy of currently available data for this level by an order of magnitude.

Authors:
; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
899114
Report Number(s):
UCRL-JRNL-220401
TRN: US0701739
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review A, vol. 74, N/A, April 5, 2006, pp. 012507
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ACCURACY; ELECTRON BEAMS; LIFETIME

Citation Formats

L?pez-Urrutia, J C, Beiersdorfer, P, and Widmann, K. Lifetime of the 1s2s 3S1 metastable level in He-like S14+ measured with an electron beam ion trap. United States: N. p., 2006. Web.
L?pez-Urrutia, J C, Beiersdorfer, P, & Widmann, K. Lifetime of the 1s2s 3S1 metastable level in He-like S14+ measured with an electron beam ion trap. United States.
L?pez-Urrutia, J C, Beiersdorfer, P, and Widmann, K. Thu . "Lifetime of the 1s2s 3S1 metastable level in He-like S14+ measured with an electron beam ion trap". United States. doi:. https://www.osti.gov/servlets/purl/899114.
@article{osti_899114,
title = {Lifetime of the 1s2s 3S1 metastable level in He-like S14+ measured with an electron beam ion trap},
author = {L?pez-Urrutia, J C and Beiersdorfer, P and Widmann, K},
abstractNote = {A precision measurement of the lifetime of the lowest exited level of the He-like S{sup 14+} ion carried out at the Livermore EBIT-II electron beam ion trap yielded a value of (703 {+-} 4) ns. Our method extends the range of lifetime measurements accessible with electron beam ion traps into the nanosecond region and improves the accuracy of currently available data for this level by an order of magnitude.},
doi = {},
journal = {Physical Review A, vol. 74, N/A, April 5, 2006, pp. 012507},
number = ,
volume = ,
place = {United States},
year = {Thu Mar 16 00:00:00 EST 2006},
month = {Thu Mar 16 00:00:00 EST 2006}
}
  • A precision measurement of the lifetime of the lowest excited level of the He-like S{sup 14+} ion carried out at the Livermore EBIT-II electron beam ion trap yielded a value of (703{+-}4) ns. Our method extends the range of lifetime measurements accessible with electron beam ion traps into the nanosecond region and improves the accuracy of currently available data for this level by an order of magnitude.
  • We present the details of an accurate lifetime measurement of the 1s{sup 2}2s{sup 2}2p {sup 2}P{sub 3/2}{sup o} metastable level in boronlike Ar XIV performed at the Heidelberg electron beam ion trap [A. Lapierre et al., Phys. Rev. Lett. 95, 183001 (2005)]. The lifetime was inferred from decay curves resulting from deexcitation of the metastable level to its {sup 2}P{sub 1/2}{sup o} ground state through a magnetic-dipole (M1) transition upon cyclically turning on and off the electron beam. The measured lifetime of 9.573(4)((+12/-5)) ms (stat)(syst) is in disagreement with a trend of theoretical predictions of 9.53(1) ms, which include themore » effect of the electron anomalous magnetic moment. Systematic effects were investigated by studying with high statistical significance the dependence of the decay times of the curves on various trapping conditions. The asymptotic trend of the decay times observed for increasingly high trapping potentials, which indicates negligible ion losses within a ms time scale, is in agreement with a theoretical model describing the ion escape rate in electrostatic ion traps. However, for high trapping potentials, we observed an unexpected slowly decaying component suggesting the presence of trapped low-energy electrons. Their origin, dynamics, and temperature, as well as their possible effects on the measured lifetime were investigated.« less
  • An earlier electron-beam ion-trap (EBIT) lifetime measurement of the Ne[sup 8+] 1s2s hthinsp;[sup 3]S[sub 1] level has been improved upon, reducing the uncertainties to less than the scatter in the existing theoretical calculations. The new result, 91.7[plus minus]0.4 [mu]s, agrees with the previous value, but is more precise by a factor of 4. The new value distinguishes among theoretical values, as agreement is obtained only with those calculations that employ [open quotes]exact[close quotes] nonrelativistic or relativistic wave functions. Routes to measurements with even higher accuracy are discussed. [copyright] [ital 1999] [ital The American Physical Society]
  • Heavy He-like ions are considered to be promising candidates for atomic parity-nonconservation (PNC) studies, thanks to their relatively simple atomic structure and the significant mixing between the almost degenerate (for the atomic numbers Z{approx}64 and Z{approx}91) opposite-parity levels 1s2s {sup 1}S{sub 0} and 1s2p {sup 3}P{sub 0}. A number of experiments exploiting this level mixing have been proposed, and their implementation requires a precise knowledge of the 2 {sup 3}P{sub 0}-2 {sup 1}S{sub 0} energy splitting for different nuclear charges and isotopes. In this paper we performed a theoretical analysis of the level splitting, employing the relativistic many-body perturbation theorymore » and including QED corrections for all isotopes in the intervals 54{<=}Z{<=}71 and 86{<=}Z{<=}93. Possible candidates for future experimental PNC studies are discussed.« less
  • An electron-beam ion trap has been used to study the spectra of highly ionized barium. Spectra of N-, O-, and F-like barium were produced by 10-keV electron-impact excitation and ionization and were observed using a von Hamos crystal spectrometer. Calibration lines were obtained by injection of Ti, V, Cr, and Zn into the trap and observation of H- and He-like transitions. A number of lines were identified for each of the ionization stages, and their energies were measured with a typical accuracy of about 150 ppm. These measurements have been compared to calculations using a multiconfigurational Dirac-Fock code. Agreement withmore » the data is best for the F-like transitions, and diminishes for transitions in the more highly charged ions.« less