Strong n-α Correlations Observed in Muon Catalyzed t-t Fusion Reactions

Abstract

We conducted X-ray and neutron measurements associated with muon catalyzed t-t fusion process using high-purity tritium solid and liquid targets. We observed K α X-rays originating from muonic helium atoms (μα) formed in the muon sticking process: t + t + μ → μα + n + n + Q (11.33 MeV), and determined the Doppler shift broadening width which gave the average value of kinetic energy distribution of μα atoms in the target. We estimated then the maximum kinetic energy of μα atoms, which agreed well with the calculated kinetic energies assuming strong n-α correlations (sequential neutron decay through intermediate 5 He resonances) in the three-particle decay at the exit channel of t+t reactions. In the neutron measurement, the t-t fusion neutrons showed a continuous energy distribution with the maximum energy at 9 MeV. The obtained shape of neutron-energy distribution was analyzed and reproduced well by a simple model of two neutron-energy components, where we also assumed strong n-α correlations in the three-particle decay. Both the average kinetic energy of recoiling μα atoms and the characteristic feature of the observed neutron-energy spectrum supported a possibility of strong n-α correlations at the exit channel of t+t reactions.