Production of a Fully Spin-Polarized Ensemble of Positronium Atoms
Abstract
Long-lived |m|=1 positronium (Ps) atoms are produced in vacuum when high density bursts of positrons with net polarization p0 are implanted into a porous silica film in a 2.3 T magnetic field. We observe a decrease in the |m|=1 population as the density of the incident positron beam is increased due to quenching interactions between oppositely polarized Ps atoms within the target. Saturation of this density dependent quenching indicates that the initial positron spin polarization p0=28±1%, and demonstrates the long term (102s) survival of positron polarization in a Surko-type buffer gas trap. We conclude that, at high Ps densities, the minority spin component is essentially eliminated and the remaining Ps is almost entirely (∼96%) polarized, as required for the formation of a Ps Bose-Einstein condensate.
- Publication:
-
Physical Review Letters
- Pub Date:
- April 2010
- DOI:
- 10.1103/PhysRevLett.104.173401
- Bibcode:
- 2010PhRvL.104q3401C
- Keywords:
-
- 36.10.Dr;
- 34.80.Nz;
- Positronium muonium muonic atoms and molecules;
- Spin dependence of cross sections;
- polarized electron beam experiments