RECOIL-DISTANCE METHOD FOR NUCLEAR LIFETIME MEASUREMENTS - STATES OF NA22,NE22 AND F19

The recoil-distance (or plunger) measurements of lifetimes of excited states produced in the bombardment of F19 by 5.5-MeV α particles is reported. A detailed discussion of small corrections involved in the analysis of these measurements is also p esented. The corrections discussed are due to finite velocity spread of recoils, spread in distance between the target and plunger, effects of perturbation of γ-ray angular distributions, and various efficiency and solid-angle effects. The mean lives determined are as follows: Na22* (0.891 MeV): 14.4±0.7 psec; Na22* (1.528 MeV): 5.0±0.7 psec; Na22* (2.211 MeV): 20.8±1.0 psec; F19* (1.346 MeV): 4.7±0.6 psec; and Ne22* (1.275 MeV): 4.6±0.5 psec. © 1969 The American Physical Society.