Effects of Impurities in the Cycle of Muon Catalyzed Nuclear Fusion (muCF)

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It is well known that a muon stopped in hydrogen catalytically induces nuclear fusion of deutron and triton. However, basic processes included in the fusion cycle are still an open problem. In our program, we studied the Coulomb capture process of exotic particles of muons and pions into molecular and atomic orbitals, and the transfer process of exotic particles X from a neutral <pX^-> to heavier atoms.The experiments were carried out at the 12 GeV proton synchrotron facility in the National Laboratory for High Energy Physics. Capture probabilities of a pion in respective atoms constituting a molecule were measured by detecting pionic x rays with an intrinsic germanium detector for elements with atomic number Z greater than 2. For hydrogen, a gamma-ray pair from a decaying neutral pion produced through the charge exchange reaction between the pion and a proton were detected with large lead glass Cherenkov detectors.A pion is caught into either an atomic orbital or a large mesomolecular orbital. The pion in mesomolecular orbital cascades down to an atomic orbital of constituting atoms through the Auger process. The probabilities of cascade process to the respective atoms depend on net atomic charges on the atoms.In a binary gas mixture, a small neutral particle of <pX^-> formed following the exotic-particle capture in a hydrogen orbital can get into impurity gas and transfer the exotic particle to the atom. It has been found that this transfer process depends strongly on the molecular structure of the impurity gas.