Nuclear magnetic moment of 59Cu with on-line β-NMR on oriented nuclei

Abstract

The nuclear magnetic moment of the nucleus 59Cu, with one proton and two neutrons outside the closed N=Z=28 shells, was measured in an on-line experiment combining β-NMR with low temperature nuclear orientation and with particle detectors operating at a temperature of about 10 K. From the data the center frequency v(Bext=0) = 209.51(22) MHz was derived. Using the hyperfine field of Cu in host iron from the literature the result for the moment is μ,[59Cu] = +1.891 (9) μN, which reveals a large deviation from the proton p3/2 single-particle value. This provides strong experimental evidence for a massive shell breaking at 56Ni.