Proton(p) and two-proton(2p) emissions from the proton-rich nuclei with 10≤Z≤20 have been explored by the in-fight decay and implantation decay methods, respectively, in a series of experiments at the HIRFL-RIBLL facility. The in-flight 2p emissions from the excited states of ^(28,29)S/^(26,27)P and ^(17,18)Ne were studied by complete-kinematics measurements. Mechanisms of 2p decay and related p-p correlations have been explored. Obvious 2p correlated emissions have been observed in the cases of ^(28,29)S but not in ^(27,28)P, indicating the 2p halo plays an important role in the diproton emission. In the ^(17,18)Ne cases, a small 2p opening angles were deduced by the HBT analyses, implying the BCS-BEC crossover may occur in the dilute nuclear matter. Moreover,^(27)S/^(26)P/^(25)Si,^(22)Si/^(20)Mg,^(23)Si/^(22)Al/^(21)Mg,^(24)Si/^(23)Al, and ^(36,37)Ca were implanted in a thin double-sided-silicon-strip detector and their β-delayed p and 2p decays have been measured by a surrounding silicon detector array under the continuous-beam mode. Important information on the nuclear spectroscopy, such as energy, lifetime, branching-ratio, and so on, has been extracted, which helps us to understand the nuclear structures of proton-rich exotic nuclei close to the drip-line.
The experiments of two-alpha emission from 17,18Ne excited levels were performed at the HIRFL-RIBLL facility of the Institute of Modern Physics, Lanzhou. The beams of 17Ne at the energy of 49.9 MeV/u and 18Ne at 51.8 MeV/u bombarded a 197Au target to populate excited states of 17,18Ne via Coulomb excitation. Complete kinematics measurements were achieved by the detectors of a silicon strip and CsI+PIN array. The experimental results combined with simple MC simulations show the characteristic of sequential two-alpha emission via 14O excited states for 18Ne. The results of two-alpha emission from 17Ne are preliminary and need further analyses.
