Abstract
A high-efficiency cascade-photon-coincidence lifetime-measuring apparatus has been used to study the 5d →5p →5s cascade in Kr ii and the 6d →6p →6s cascade in Xe ii. A neutral atomic beam was excited and ionized by electron impact, and the spontaneously emitted photons were collected by an ellipsoidal mirror and detected by fast photomultipliers provided with narrow-band interference filters. The spectrum of time delays was acquired by a time-to-amplitude converter and multichannel pulse-height analyzer. The lifetime of the Kr ii 5p state was found to be 7.004±0.053 ns. This is in agreement with two previous high-precision measurements and represents an improvement in precision by a factor of 3.6. The Xe ii 6p lifetime was found to be 9.494±0.067 ns. This result agrees with several measurements of lower accuracy, but is in clear disagreement with two previous measurements claiming high precision, which disagree with each other as well.
- Received 10 December 1991
DOI:https://doi.org/10.1103/PhysRevA.45.4452
©1992 American Physical Society