Moderation and diffusion of positrons in tungsten meshes and foils

A. I. Williams, D. J. Murtagh, S. E. Fayer, S. L. Andersen, J. Chevallier, Kövér, P. Van Reeth, J. W. Humberston, G. Laricchia

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The efficiency of tungsten meshes and thin foils for moderation of fast positrons from 22Na has been investigated in transmission geometry and a fair agreement has been found with previous experimental results where directly comparable. For foils, the dependence on material thickness is found to be similar to the prediction of the Vehanen-Mäkinen diffusion model; however, the magnitude is 5-10 times lower. A broad consensus is observed between experiment and the results of a three-dimensional model developed in this work. For a given thickness, meshes are found to be generally better than foils by around a factor of 10 with a maximum efficiency (∼10-3) comparable to that achieved with thin single crystal foils, in accord with previous measurements and the results of the present model.

Original languageEnglish
Article number105302
JournalJournal of Applied Physics
Issue number10
Publication statusPublished - Sep 14 2015

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Williams, A. I., Murtagh, D. J., Fayer, S. E., Andersen, S. L., Chevallier, J., Kövér, Van Reeth, P., Humberston, J. W., & Laricchia, G. (2015). Moderation and diffusion of positrons in tungsten meshes and foils. Journal of Applied Physics, 118(10), [105302].