Muon-spin-rotation study of muon polarization losses in plastic scintillators and quartz

Muon polarization losses in plastic scintillators of two types and in fused quartz have been studied by the $\mu$SR method. The muon and muonium spin precession spectra have been measured on the $\mu$SR setup placed at the output of the muon channel of the Gatchina synchrocyclotron. It has been shown that a significant fraction of stopped muons participate in the formation of the muonium. As a result, these muons lose their polarization completely. The magnitude of muon depolarization depends considerably on the type of plastic. It has been found that the muon spin precession frequency in fused quartz in an external magnetic field ($F_{\text{Q},\mu}=0.116\pm0.002$ MHz) is shifted with respect to that in plastic scintillators ($F_{1,\mu} = 0.101\pm0.005$ MHz and $F_{2,\mu}= 0.101\pm0.002$ MHz).