Oscillations in Orthopositronium Annihilation in Magnetic Field in SiO_{2} Powders

The phenomenon of oscillations of positronium 3γ-decay quantum angular distribution in magnetic field was predicted in papers [1, 2] and the idea of realization opportunity of the new matter investigating method with the use of positrons was put forward. Polarized positrons are slowed down in matter to form the polarized positronium atom. The anisotropy of the 3γ-decay quantum angular distribution relative to the positronium atom quadupolarization will bring time oscillations of the count rate which can be experimentally observed in recording delayed coincidences between the nuclear γ-quantum (22 Νa) and annihilation quanta. By analogy with the μSR-method the new technique was called the positronium spin rotation (PsSR) method [2]. The oscillation frequencies correspond to the differences in energy of Ps atom levels in the magnetic field