6533b832fe1ef96bd129abb6

RESEARCH PRODUCT

αdecay of the new isotope206Ac

subject

description

The new neutron-deficient nuclide {sup 206}Ac was produced by bombarding a {sup 175}Lu target with 5.5 MeV/nucleon {sup 36}Ar ions. The evaporation residues were separated in flight by a gas-filled separator and subsequently identified by the {alpha}-{alpha} position and time correlation method. {sup 206}Ac was found to have two {alpha} particle emitting isomeric levels with half-lives of (22{sub {minus}5}{sup +9}) ms and (33{sub {minus}9}{sup +22}) ms, and with {alpha} particle energies of (7790{plus_minus}30) keV and (7750{plus_minus}20) keV, respectively. The former isomer is tentatively assigned to a J{sup {pi}}=3{sup +} level and the latter to a J{sup {pi}}=10{sup {minus}} level, both of which are also seen in the daughter and granddaughter nuclides {sup 202}Fr and {sup 198}At. Improved values of (27{sub {minus}6}{sup +11}) ms and (7693{plus_minus}25) keV for the half-life and {alpha} particle energy of {sup 207}Ac are also reported. {copyright} {ital 1998} {ital The American Physical Society}