Williams, AI;
Murtagh, DJ;
Fayer, SE;
Andersen, SL;
Chevallier, J;
Kövér, Á;
Van Reeth, P;
... Laricchia, G; + view all
(2015)
Moderation and diffusion of positrons in tungsten meshes and foils.
Journal of Applied Physics
, 118
(10)
10.1063/1.4930033.
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Abstract
The efficiency of tungsten meshes and thin foils for moderation of fast positrons from <sup>22</sup>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<sup>-3</sup>) comparable to that achieved with thin single crystal foils, in accord with previous measurements and the results of the present model.
| Type: | Article |
|---|---|
| Title: | Moderation and diffusion of positrons in tungsten meshes and foils |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1063/1.4930033 |
| Publisher version: | http://dx.doi.org/10.1063/1.4930033 |
| Language: | English |
| Additional information: | © 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1471220 |
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