Muonium atoms and intraspur processes in water

Abstract

Since muonium atoms come into existence as a result of stopping energetic positive muons, it has been suggested that intraspur reactions (primarily with thermalized electrons or OH radicals, in water) are responsible for: (i) muonium formation, (ii) direct generation of a fraction of the muons in diamagnetic molecules, and (iii) the ’’missing’’ muon polarization. These postulates are examined in detail by adding scavengers which can preclude intraspur reactions without reacting with muonium. The results show convincingly that intraspur processes are insignificant in (i) and (ii). Furthermore, they could only be important in (iii) if a spin-exchange process occurred with a frequency which was much greater than the ordinary diffusion-limited encounter frequency. Rather than this ’’spur model’’, the data obtained are consistent with the ’’hot model’’, whereby hot muonium atoms form beyond the spurs of the muon track.