Nuclear polarization of the ground state of $^{57}$Cu produced through a nucleon pick up reaction at the primary beam energy 140 MeV/nucleon

In order to measure the magnetic moment of the ground state of $^{57}$Cu($I^{\pi }$ = 3/2$^{-}$, $T_{1/2}$ = 199 ms), which is one proton outside doubly-magic $^{56}$Ni, a polarized $^{57}$Cu beam has been developed at NSCL/MSU. $^{57}$Cu ions were produced through a (p, 2n) reaction process of a 140 MeV/nucleon $^{58}$Ni primary beam on Be target and separated from other products in the A1900 fragment separator. To produce polarization, $^{57}$Cu ions ejected at an angle of 2 degree relative to the normal beam axis were selected. Polarized $^{57}$Cu ions were implanted into a single-crystal NaCl under an external magnetic field $H_{0} \quad >$ 0.1 T. The degree of the polarization was measured by an $H_{0}$ on and off technique with normalization runs without polarization. The degree of the polarization as a function of the momentum of $^{57}$Cu and $H_{0}$ will be discussed.