Measurements of 3He accumulation effect on muon catalyzed fusion in the solid/liquid DT mixtures

An effect on the muon catalyzed fusion (μCF) of the 3He originating from the tritium decay was studied by measuring the time-dependent change of the fusion-neutron disappearance rate (λn) in the deuterium and tritium (DT) mixtures with various tritium concentrations, Ct=0.1, 0.2, …, 0.7. A clear difference between the solid and the liquid DT mixtures due to the 3He accumulation effect was observed: in solid λn increased with the time after solidification, whereas in liquid λn did not change. This indicates that 3He produced in the solid DT mixtures is trapped. Admitting that all the 3He remain in solid, the muon transfer rate from tμ to 3He is determined to be about 4×109 s−1, consistent with the theoretical prediction.