Muonium formation on powdered platinum surfaces

Abstract Muonium formation was verified in platinum powders under vacuum by muonium spin rotation (MuSR) spectroscopy. Muonium yields of 13(1)% and 9(3)% per incident muon were obtained for Pt powders with mean particle diameters of 30 and 200 nm, respectively. The disappearance of the muonium signal under oxygenic or atmospheric environment indicates that muonium stays outside the Pt particles. It can be postulated that reactive collision between muonium and atomic oxygen is a predominant process on the platinum surface treated by hydrogen.