摘要
The application of Lanthanum Bromide(LaBr3)detectors provides a unique opportunity to measure lifetime of excited states in picosecond-nanosecond region.Reducing the background is of critical importance to get precise results.For some excited states feeding from isomers with lifetime longer than 1μs,it can be achieved by the Spectrometer for Heavy Atom and Nuclear Structure(SHANS)[1].143Eu nuclei were populated via the 123Sb(24Mg,4n)fusion-evaporation reaction.Most of the evaporation residues at ground state or long-lived isomers were transferred to detection terminal after a flight of about 1.4μs in SHANS.In the case of 143Eu,three transitions have been observed(Fig.1).
