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

众所周知，停在氢中的介子催化地诱导氘核和氚的核聚变。然而，包括在聚变循环中的基本过程仍然是一个悬而未决的问题。在我们的项目中，我们研究了外来粒子介子和介子进入分子轨道和原子轨道的库仑俘获过程，以及外来粒子X从中性<pX^->向较重原子的转移过程。实验是在高能物理国家实验室的12 GeV质子同步加速器设备上进行的。用本征锗探测器对原子序数Z大于2的元素探测π介子x射线，测量了π介子在组成分子的各原子中的捕获概率。对于氢，通过介子和质子之间的电荷交换反应产生的衰变中性介子产生的伽马射线对被大型铅玻璃切伦科夫探测器探测到。介子被捕获到原子轨道或大的介分子轨道上。介子在介分子轨道上通过俄歇过程级联到构成原子的原子轨道。到相应原子的级联过程的概率取决于原子上的净原子电荷。在二元气体混合物中，在氢轨道捕获外来粒子后形成的<pX^->的小中性粒子可以进入杂质气体并将外来粒子转移到原子中。研究发现，这种转移过程在很大程度上取决于杂质气体的分子结构。

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.