Muon spin rotation at SIN

Recently the accelerator and the muon channel at SIN became operational. This paper reports some of the first positive muon spin rotation experiments at SIN. The first experiment discussed concerns the chemistry of muonium. For the first time a muonium or radical signal in pure water is observed. Next, the application of the positive muon for the study of ferromagnetic metals and alloys is discussed. First measurements on a single crystal of iron around liquid helium temperature seem to indicate that at low temperature the muon does not diffuse. The first stroboscopic observation of the muon spin rotation which will allow one to take full advantage of the high stopping density at SIN is reported. (Auth.)