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Creators/Authors contains: "Hodgman, Sean"

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  1. ; ; ; (, Atoms)
    We outline an experimental technique for measuring the degree of polarization of a positron beam using an optically pumped, spin-polarized Rb target. The technique is based on the production and measurement of the ortho- and para-positronium fractions through positron collisions with the Rb atoms as a function of their polarization. Using realistic estimates for the cross sections and experimental parameters involved, we estimate that a polarization measurement with an uncertainty of 3% of the measured value can be achieved in an hour. 
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  2. ; ; ; (, The European Physical Journal D)
    Abstract We describe the production of a high-resolution electron beam using a Penning–Malmberg buffer-gas trap, or Surko trap as they have become known. A high-flux beam with an energy width of ~ 30 meV (FWHM) is readily achieved and the efficiency of production is considerably higher than that for positrons in a similar trap configuration. The reasons for this become apparent when one considers the molecular collisions and the respective selection rules involved, for electrons and positrons. We demonstrate the production of the beam and the capacity that it realises for absolute scattering measurements and for high-resolution electron spectroscopy. Graphical abstract 
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