MUONIUM FORMATION AND DIFFUSION IN CONDENSED NEON

Liquid and solid neon (l-Ne and s-Ne) have been studied for the first time by the mu+SR method. Prompt muonium (Mu) formation was detected b y observation of the two-component precession signal at characteristic triplet Mu frequencies, which also revealed a Mu hyperfine interactio n close to the vacuum value in both l-Ne and s-Ne. Nearly all muons fo rm Mu in the solid phase. A very slow, nearly T-independent Mu relaxat ion rate is increased to a somewhat larger constant rate (correspondin g to static Mu atoms) by addition of any of a variety of impurities, s uggesting quenching of coherent Mu diffusion by defect strain fields.