Walk-Free Centroid Method for Lifetime Measurements with Pulsed BEAMS

摘要

A delayed-coincidence lifetime measurement method based on a comparison of walk-free centroids of time spectra is presented. The time is measured between the cyclotron RF signal and the pulse from a plastic scintillation detector followed by a fixed energy selection. The events to be time-analyzed are selected from the associated charge-particle spectrum of a silicon detector which is operated in coincidence with the scintillator, i.e., independently of the formation of the signal containing the time information. With this technique, with the micropulse FWHM of typically 500 to 700 ps, half-lives down to the 10 ps region can be measured. The following half-lives are obtained with the new method: 160+-6 ps for the 2032 keV level in exp 209 Pb; 45+-10 ps and 160+-20 ps for the 1756.8 keV (0 sub 2+ ) and 2027.3 keV (0 sub 3+ ) levels in exp 116 Sn, respectively. (Atomindex citation 09:397356)