FREEZING-OUT OF NUCLEAR-POLARIZATION IN RADIOACTIVE CORE IONS OF MICROCLUSTERS, SNOWBALLS IN SUPERFLUID-HELIUM

A novel method was tried successfully to trap ions and to freeze out t heir nuclear polarization inside aggregates of helium atoms, ''snowbal ls'', in superfluid helium. Spin polarized B-12 (T-1/2 = 20.4 ms) ions were introduced into superfluid helium and snowballs were created aro und the impinged impurity ions. Beta-ray asymmetry was measured to obt ain the nuclear polarization of decaying B-12. The comparison with the initial value of B-12 polarization produces that no relaxation in pol arization was observed throughout lifetime of B-12.