Measurement of the muon transfer rate from deuterium to ³ at low temperature

Abstract

The muon transfer rate $(\tilde \lambda _{d{\text{ }}^{\text{3}} {\text{He}}} )$ from deuterium to ³ at temperatures of 39.5 K and 50.0 K, respectively, has been determined as a by-product of the experiment aimed to search for muon catalyzed d ³He-fusion. The measurements were performed in the muon beam at PSI with a multi-anode high pressure ionization chamber as a target and detector of the incoming muons and the charged reaction products. The chamber was filled with the HD + ³He(5.6%) gas mixture of 9.21% LHD density. The analysis of time distributions of dd-fusion events was able to determine the transfer rates: $\tilde \lambda _{d{\text{ }}^{\text{3}} {\text{He}}}$(50 K)=(2.32± 0.09)× 10⁸ s^-1, $\tilde \lambda _{d{\text{ }}^{\text{3}} {\text{He}}}$(39.5 K)=(2.33± 0.16)·10⁸ s^-1. These values, normalized to liquid hydrogen density (LHD, 4.25· 10²² atoms/cm³), significantly exceed the transfer rates at room temperature, in agreement with theoretical predictions.