Berlin 2001 – wissenschaftliches Programm
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A: Atomphysik
A 17: Posters Friday (Spectroscopy)
A 17.32: Poster
Freitag, 6. April 2001, 12:30–15:00, AT3
Lifetime measurement of He− utilizing the electrostatic ion storage ring ELISA — •Ulrik Vindelev Pedersen1, Mikkel Hyde2, Søren Pape Møller1, and Torkild Andersen2 — 1Institute for Storage Ring Facilities, University of Aarhus, DK-8000 Aarhus C, Denmark — 2Institute of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C, Denmark
The electrostatic heavy-ion storage ring ELISA has been utilized to measure the lifetime of the metastable 1s2s2p 4P5/2 level of the He− ion together with the average lifetime of the 4P1/2 and 4P3/2 levels. This storage ring allows lifetime measurements to be performed without the influence of magnetic fields and at temperatures down below −50 ∘C which reduces photodetachment of He− due to blackbody radiation. The lifetime of the 4P5/2 level has been determined to be 365 ± 3 µs in agreement with, but more accurate than a previous magnetic storage ring measurement and 6% longer than the lifetime recently reported utilizing an electrostatic ion trap (Wolf et al., Phys. Rev. A 59, 267 (1999)). The average lifetime of the 4P1/2 and 4P3/2 levels has been determined to be 11.1 ± 0.3 µs, in agreement with theoretical predictions, but about 25% longer than the reported value from the electrostatic ion trap experiment.