Nuclear polarization in core ions of microclusters, ‘snowballs’ in superfluid helium

Abstract

Novel methods were applied successfully to trap ions and to freeze out their nuclear spin polarization inside aggregates of helium atoms, “snowballs” in superfluid helium. Polarized beta-ray emitting12B ions (T1/2=20.4 ms) were injected into superfluid helium and snowballs were created around the impurity ions. Beta rays were detected to locate snowballs and the beta-ray asymmetry was measured to obtain the nuclear polarization of decaying12B. The comparison with the initial value of12B polarization produces that no relaxation in polarization was observed throughout lifetime of12B.