Measuring the fusion cross-section of light nuclei with low-intensity beams

We demonstrate an approach to measure the total fusion cross-section for beams of low-intensity light nuclei. Fusion residues resulting from the fusion of 20,16O+12C are directly measured and distinguished from unreacted beam particles on the basis of their energy and time-of-flight. The time-of-flight is measured between a microchannel plate (MCP) detector, which serves as a start, and a segmented silicon detector, which provides a stop. The two main difficulties associated with the initial implementation of this approach are charge trapping in the silicon detector and slit scattering in the MCP detector. Both these obstacles have been characterized and overcome. To reduce atomic slit scattering in the measurement we have eliminated wires from the beam path by developing a gridless MCP detector. The total fusion cross-section for 16O+12C in the energy range ECM=8.0-12.0 MeV has been measured in agreement with established literature values (down to the 100 mb level).