THE NUCLEAR-STRUCTURE OF FR-227

The gamma-rays following the beta(-) decay of Rn-227 have been investi gated by means of gamma-ray singles and gamma gamma-coincidence measur ements using an array of 12 Compton-suppressed Ge detectors. The fast- timing beta gamma gamma(t) method has been used to measure six level l ifetimes. Multipolarities of 32 transitions in Fr-227 have been establ ished by measuring conversion electrons with a mini-orange electron sp ectrometer. Most of the observed transitions have been placed in a lev el scheme comprising 38 excited states of Fr-227, Th, low-lying levels are interpreted in terms of seven rotational bands. The observed E1 s trengths for two transitions connecting the K-pi = 3/2(+/-) bands are consistent with the transitional character of Fr-227, and confirm the presence of octupole correlations in this nucleus. (C) 1997 Elsevier S cience B.V.