Isomer separation of Cu-70g and Cu-70m with a resonance ionization laser ion source

Radioactive copper isotopes were ionized with the resonance ionization lase r ion sourer (RILIS) at the on-line isotope separator ISOLDE (CERN). Using the different hyperfine structure in the 3d(10) 4s S-2(1/2) - 3d(10)4p P-2( 1/2)0 transition the low- and high-spin isomers of (CU)-C-70 were selective ly enhanced by tuning the laser wavelength. The light was provided by a nar row-bandwidth dye laser pumped by copper vapor lasers (CVL) and frequency d oubled in a BBO crystal. The ground state to isomeric state intensity ratio could be varied by a factor of 30, allowing to assign gamma transitions un ambiguously to the decay of the individual isomers. It is shown that the me thod can also be used to determine magnetic moments. In a first experiment for the 1(+) ground state of Cu-70 a magnetic moment of (+)1.8(3) mu(N) and for the high-spin isomer of Cu-70 a magnetic moment of (+/-)1.2(3) mu(N) c ould be deduced. (C) 2000 Elsevier Science B.V. All rights reserved.