Experimental research into the two-proton emissions from ^(17,18) Ne,^(28) P and ^(28,29)S  

作　　者：LIN ChengJian1, XU XinXing1, JIA HuiMing1, YANG Feng1, JIA Fei1, WU ZhenDong1, ZHANG ShiTao1, LIU ZuHua1, ZHANG HuanQiao1, XU HuShan2, SUN ZhiYu2, WANG JianSong2, HU ZhengGuo2, WANG Meng2, CHEN RuoFu2, ZHANG XueYing2, LI Chen2, LEI XiangGuo2, XU ZhiGuo2, XIAO GuoQing2 & ZHAN WenLong2 1China Institute of Atomic Energy, P. O. Box 275(10), Beijing 102413, China 2 Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China 

出　　处：《Science China(Physics,Mechanics & Astronomy)》2011年第S1期73-80,共8页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos. 10675169, 10735100, and 10727505);the Major State Basic Research Developing Program (Grant No. 2007CB815003)

摘　　要：Two-proton emissions from the excited states of 17,18Ne, 28P and 28,29S were investigated experimentally by the radioactive beams bombarding on the 197Au target via the Coulomb excitation. The complete-kinematics measurements were actualized by the stacks of silicon-strip detectors and CsI+PIN array detectors. The invariant mass of final systems as well as the relative momentum, opening angle, and relative energy of the two emitted protons was reconstructed under the framework of relativ istic kinematics. Visible proton-proton correlations were observed in these systems. The mechanisms of two-proton emission were analyzed in a simple schematic model, in which the extreme decay modes like He cluster emission, three-body 2 phase-space decay, and two-body sequential decay were taken into account. With the help of Monte-Carlo simulations, the two protons emitted from the 6.15 MeV excited state of Ne and the excited states in the energy region of 9.6–10.4 MeV of S, 18 29 respectively, exhibited prominent features of2 He cluster decay while for the other cases, no obvious diproton emissions were observed.Two-proton emissions from the excited states of 17,18Ne, 28P and 28,29S were investigated experimentally by the radioactive beams bombarding on the 197Au target via the Coulomb excitation. The complete-kinematics measurements were actualized by the stacks of silicon-strip detectors and CsI+PIN array detectors. The invariant mass of final systems as well as the relative momentum, opening angle, and relative energy of the two emitted protons was reconstructed under the framework of relativ istic kinematics. Visible proton-proton correlations were observed in these systems. The mechanisms of two-proton emission were analyzed in a simple schematic model, in which the extreme decay modes like He cluster emission, three-body 2 phase-space decay, and two-body sequential decay were taken into account. With the help of Monte-Carlo simulations, the two protons emitted from the 6.15 MeV excited state of Ne and the excited states in the energy region of 9.6–10.4 MeV of S, 18 29 respectively, exhibited prominent features of2 He cluster decay while for the other cases, no obvious diproton emissions were observed.

关 键 词：two-proton emission RADIOACTIVE ion beam complete-kinematics measurement He cluster DECAY THREE-BODY 2 PHASE-SPACE DECAY two-body sequential DECAY 

分 类 号：O571.3[理学—粒子物理与原子核物理]