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Conservation of longitudinal spin polarization of positrons emitted from a thin Ni(100) foil

G. G. Cecchini*, R. G. Greaves, and A. P. Mills, Jr.

  • Department of Physics and Astronomy, University of California Riverside, Riverside, California 92506, USA

  • *Gcecc001@ucr.edu
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Phys. Rev. A 107, 062809 – Published 9 June, 2023

DOI: https://doi.org/10.1103/PhysRevA.107.062809

Abstract

We have discovered that 5 keV bursts of 5×107 positrons with an initial longitudinal spin polarization of (28.8±0.7)%, when implanted into a thin Ni(100) crystal, are emitted with 20% efficiency at thermal energies from its surface with (30.9±0.5)% polarization. We conclude that the positron spin polarization is preserved while interacting with the Ni, despite the 0.61 T average transverse magnetization of the Ni at room temperature. The resulting polarized beam has been focused to a 0.025-mm mean-diameter spot when accelerated to 5 keV and will be uniquely suited for experiments on a neutral spin aligned e+−e− plasma, spin- and angle-resolved positronium emission spectroscopy, and critical for producing a triplet positronium Bose-Einstein condensate.

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Outline

Information

Phys. Rev. A 107, 062809– Published 9 June, 2023
  • Received 17 December 2022
  • Revised 15 March 2023
  • Accepted 16 May 2023
Article part of CHORUS
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