Resonant dd mu formation in condensed deuterium - art. no. 052705

The rate of dd mu muonic-molecule resonant formation in d mu atom collision s with a condensed deuterium target is expressed in terms of a single-parti cle response function. In particular, dd mu formation in solid deuterium at low pressures is considered. Numerical calculations of the rate in the cas e of fee polycrystalline deuterium at 3 K have been performed using the iso tropic Debye model of a solid. It is shown that the energy-dependent dd mu formation rates in the solid differ strongly from those obtained for D-2 ga seous targets, even at high d mu kinetic energies. Monte Carlo neutron spec tra from dd fusion in dd mu molecules have been obtained for solid targets with different concentrations of orthodeuterium and paradeuterium. The rece nt experimental results performed in low-pressure solid targets (statistica l mixture of ortho-D-2 and para-D-2) are explained by the presence of stron g recoil-less resonance peaks in the vicinity of 2 meV and very slow decele ration of d mu atoms below 10 meV. Good agreement between the calculated an d experimental spectra is achieved when a broadening of D-2 rotational and vibrational levels in solid deuterium is taken into account. It has been sh own that resonant dd mu formation with simultaneous phonon creation in the solid gives only about 10%, contribution to the fusion neutron yield. The n eutron time spectra calculated for pure ortho-D-2 and paraD(2) targets are very similar. A practically constant value of the mean dd mu formation rate , observed for different experimental conditions, is ascribed to the fact t hat all the recent measurements have been performed at temperatures T less than or similar to 19 K. much lower than the target Debye temperature Theta (D) approximate to 110 K. In result, the formation rate, obtained in the l imit T/Theta (D)much less than1, depends weakly on the temperature.