Stroboscopic Observation of Nuclear Larmor Precession

A new resonance method is described which is suited for the measurement of hyperfine interactions at nuclear isomers with mean lives longer than 1 μsec. The method is characterized by pulsed-beam production of excited nuclei, the Larmor frequency of which is determined by a coherent superposition of the perturbed angular correlation originating from different beam pulses. An experiment was performed on a 4-μsec state of ${}_{}{}^{69}{}_{}{}^{}\mathrm{Ge}$. The $g$ factor was determined as $g=-0.2224\mathrm{}\pm 0.0007$.