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

An effect on the muon catalyzed fusion (mu CF) of the He-3 originating from the tritium decay was studied by measuring the time-dependent change of th e fusion-neutron disappearance rate (lambda(n)) in the deuterium and tritiu m (DT) mixtures with various tritium concentrations, C-t = 0.1,0.2,...,0.7. A clear difference between the solid and the liquid DT mixtures due to the He-3 accumulation effect was observed: in solid lambda(n) increased with t he time after solidification, whereas in liquid lambda(n) did not change. T his indicates that He-3 produced in the solid DT mixtures is trapped. Admit ting that all the He-3 remain in solid, the muon transfer rate from t mu to He-3 is determined to be about 4 x 10(9) s(-1), consistent with the theore tical prediction. (C) 1999 Published by Elsevier Science B.V. All rights re served.