| Autor: |
Williams, A. I., Murtagh, D. J., Fayer, S. E., Andersen, S. L., Chevallier, J., Kövér, Á., Van Reeth, P., Humberston, J. W., Laricchia, G. |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; 2015, Vol. 118 Issue 10, p105302-1-105302-5, 5p, 1 Black and White Photograph, 1 Chart, 3 Graphs |
| Abstrakt: |
The efficiency of tungsten meshes and thin foils for moderation of fast positrons from 22 Na 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. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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