Multi-nucleon transfer reaction studies of 6HE on 12C at 30 MeV using the SHARC and TIGRESS arrays

Abstract

Two multi-nucleon transfer reactions were studied using 6He on 12C with the Silicon Highly-segmented Array for Reactions and Coulex (SHARC), a compact charged particle silicon array, and the TRIUMF-ISAC Gamma-Ray Escape Suppressed Spectrometer (TIGRESS), a high-efficiency gamma-ray detector, at the TRIUMF ISAC-II facility. First, the reaction mechanisms of the (6He, 4He) two-neutron transfer were studied to determine the dominant mechanism; one-step simultaneous transfer or two-step sequential transfer. Second, the multi-nucleon transfer (6He, 8Be) reaction was observed and its reaction mechanism could proceed two ways, by a two-proton transfer or an alpha transfer. The two-neutron and multi-nucleon transfer reactions were analyzed and angular distributions extracted. These angular distributions were then compared to the microscopic models investigating the effects of the simultaneous vs. sequential transfer mechanisms. Detailed simulations in GEANT4 were performed of the SHARC array to characterize detector performance. This thesis will discuss the experimental challenges, the data analysis, GEANT4 reaction simulations and interpretation of the data within the reaction models.