Study of muon catalyzed dd-fusion in HD gas

The results of an experiment on muon catalyzed dd-fussion in HD gas are pre sented. The experiment was performed at the muon beam of PSI using a high-p ressure ionization chamber filled with pure HD-gas of low D-2 concentration on the level 1%, at temperatures 50, 150 and 300 K. The non-resonant chara cter of dd mu-molecule formation on HD molecules was confirmed by measuring the ratio of yields of the two dd mu-fusion channels, R = Y(He-3,n)/Y(H-3, p), which proved to be close to unity. The dd mu formation rate was found t o vary from lambda(dd mu-HD) = 0.05.10(6) s(-1) at T = 50 K to lambda(dd mu -HD) = 0.12.10(6) s(-1) at T = 300 K, in agreement with the theoretical pre diction. A prominent peak at t < 60 ns was observed in the time spectrum of fusion neutrons indicating a resonant contribution of dd\mu formation from epithermal d\mu atoms.