MU+ DIFFUSION AND TRAPPING IN HIGH-PURITY AND OXYGEN-DOPED NB

Data are presented for the temperature dependence of the muon depolarization rate between 10 K and 120 K for three samples of niobium of varying. purity. Two samples, each containing approximately 200 ppm substitutional Ta and interstitial concentrations of 10 ppm and 560 ppm (mostly O), respectively, were studied. A third sample containing only 3 ppm Ta and an estimated 10 ppm total interstitial impurities was also measured. The results indicate that even at the lowest temperatures studied the depolarization of the muon is dominated by traps associated with impurities. © 1979 North-Holland Publishing Company.