beta-decay studies of the neutron-rich N-18,N-21 isotopes

The beta-decay studies of neutron-rich N-18,N-21 isotopes have been performed using beta-n, beta-gamma, and beta-n-gamma coincidence methods. The N-18,N-21 ions were produced by the fragmentation of the Ne-22 and Mg-26 beams, respectively, on a thick beryllium target. The time of flight of the emitted neutrons following the beta-decay of N-18,N-21 was measured by a neutron detector system with wide energy detection range and low-energy detection threshold. In addition, several clover germanium detectors were used to detect the beta-delayed gamma-rays. The half-lives of the beta-decays of N-18 and N-21 were determined to be (619+/-2) ms and (82.9+/-7.5) ms, respectively. Several new beta-delayed neutron groups were observed with a total branching ratio of (6.98+/-1.46)% and (90.5+/-4.2)% for N-18 and N-21, respectively. The level schemes of O-18 and O-21 were deduced. The experimental Gamow-Teller beta-decay strengths of N-18 and N-21 to these levels were compared with the shell model calculations.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000302529300010&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Physics, MultidisciplinarySCI(E)5ARTICLES53-S605