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 $P={0.22}_{\ensuremath{-}0.02}^{+0.04}$. Improved design could increase $P$ to 0.40 with a flux of ${10}^{5}$-${10}^{6}$/sec. Applications of this discovery are discussed.