Measurement of beta(+) delayed alpha decay of Na-20

Through the Na-20 (beta (+))under right arrow(20)Ne*--> O-16+ alphaa proces s, the half-life and beta (+) delayed a decay spectrum of Na-20 have been m easured on the Radioactive Ion Beam Line in Lanzhou (RIBLL). The Na-20 was identified through TOF-DeltaE method and alpha particle was measured by fou r Si(Au) surface barrier detectors. The half life of Na-20 is(459 +/-7)ms. Result shows that in addition to nine high excitation energy levels with E( d)greater than or equal to2.688MeV, three low excitation energy levels of N a-20 with E-d = 0.890 & 1.054, 1.991, 2.424 & 2.457MeV were observed in the experiment. The relative intensity for 1.991MeV level, a more important en ergy level in the center of mass system energy region from 1.6 to 2.5MeV ob tained in this experiment is much higher than the existed one. We also obta ined the relative intensities of the levels of E-d =0.890 & 1.054, 2.424 & 2.457MeV.