Quadrupole moments of isomers in the A=90 region and the tilted-foil polarization of a separated reaction-product beam

The quadrupole interaction of polarized 92Mo(8+,τ=0.29 μs) and 93Ru(21/2+,τ=3.5 μs) isomers in a single crystal of Zr has been measured. The experiment utilizes the nuclear polarization induced by the tilted-multifoil interaction with separated isomer beams from a mass spectrometer. The magnitudes and signs of the quadrupole moments were deduced to be -0.33 and +0.04 b for 92Mo(8+) and 93Ru (21/2+), respectively. Together with previous work on the 88,90Zr(8+) isomers, this experiment sheds light on the particle-hole shell-model structure in the A=90 region. It also serves as a calibration of a recent experiment on parity mixing in the 17/2--17/2+ doublet in 93Tc. The induced nuclear polarization under the conditions of a separated reaction-product beam is found to be substantially higher than in previous in-beam experiments