Rui-chang Ma

Newβ-delayed proton precursor135Gd

Unknownβ-delayed proton precursor135Gd has been synthesized by the reaction106Cd (32S, 3n) and identified using a helium-jet recoil fast tape-transport system with aγ(X)-p coincidence measurements. Itsβ-delayed proton spectrum has been observed. The half-life of135Gd decay has been determined to be 1.1±0.2 s.

Neaw β-delayed proton precursor121Ce near the proton drip-line

Unknown β-delayed proton precursor121Ce was produced via the reaction of92Mo(32S, 3n), and identified by an He-jet fast tape transport system with “P-γ” coincidence measurements. The half-life of121Ce decay was determined to be (1.1 ± 0. l)s. Its energy spectrum of β-delayed protons was measured and the β-delayed proton branching ratio for121decay was roughly estimated to be ∼ 1 %. After β-delayed proton decay of the precursors119Ba,121Ba and122La, some of γ-transitions from low-lying states to the ground states in their “daughters” were observed for the first time.

Decay study of20Na and its beta-delayed16O recoiling

The decay of20Na of astrophysical reactions has been studied deeply via20Ne(p, n)20Na reaction. A new β-delayed α decay with α energy of 5 896 ± 6 keV and relative intensity of 0.002 4 ± 0. 000 3 was discovered. At the same time the16O recoiling in β+-delayed α decay of20Na was observed in experiment for the first time. From these, it is inferred that a β-delayed low energy α decay of20Na with energy of ∼780 keV and relative intensity of ∼1.4 was mixed in16O recoiling. In16O recoiling and the low energy α decay, the energy loss for low energy charged particles through matter was discussed in detail. At last, two methods for discriminating the β-delayed low energy α decay of20Na were proposed.