Spin Polarization of Low-Energy Positron Beams

Abstract

It is discovered that the 1-eV positrons formed on an MgO-coated moderator with use of positrons from a ${}_{}{}^{58}{}_{}{}^{}\mathrm{Co}$ source are polarized with degree of polarization $P={0.22}_{-0.02\mathrm{}}^{+0.04\mathrm{}}$. Improved design could increase $P$ to 0.40 with a flux of ${10}^5$-${10}^6$/sec. Applications of this discovery are discussed.