Generation of very slow polarized positive muons

Abstract

We have measured the polarization of very slow positive muons (kinetic energy \ensuremath{\sim}10 eV) obtained from the moderation of a 100% polarized surface muon beam in rare gas solid layers. We find that the muons nearly retain their initial polarization, indicating that the moderation process is very fast compared to depolarizing mechanisms. This result opens the possibility of producing beams of very low energy polarized muons, which have a wide range of possible applications, e.g., as a magnetic microprobe of surfaces and thin films.