In-beam measurement of beta(+) delay particle decay on RIBLL

The in-beam measurement of beta (+) delay a decay of Na-20 on the Radioacti ve Ion Beam Line in Lanzhou(RIBLL) is reported. The radioactive ion Na-20 w as identified in-beam by means of TOF - DeltaE method. The implantation dep th of the secondary beam in the detectors was optimized by a group of degra ders with different thickness. The procedure of data acquisition was divide d into two stages, i. e., in-beam and off-beam stage, to record the RIB and the beta (+) delay a particles respectively. Four resonant energy levels, 2.69, 3.09, 4.74, and 5.54MeV of Ne-20, have been observed with their relat ive amplitudes of 100, 4.15, 1.10 and 15.2, respectively. The half-life of Na-20(beta+) --> Ne-20* --> O-16+ alpha decay is preliminarily determined t o be 459ms by using a time scaler combined with a pulse generator. The resu lts are in good agreement with the ones of other group.