https://doi.org/10.1140/epjd/e2014-40807-2
Regular Article
Optimisation of the thickness of the moderator for positron annihilation process study in Ar gas*
1 Institute for Excellence in Higher
Education, Tohoku University, 980–8576
Sendai,
Japan
2 Department of Chemistry, Tohoku
University, 980–8578
Sendai,
Japan
a e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Received:
17
December
2013
Received in final form:
3
February
2014
Published online:
23
June
2014
Abstract
To investigate the deceleration and annihilation processes of positron in noble gas, we attempted to optimise the thickness of the positron moderator. The results of the decreasing trend of free positron intensity and ortho-positronium intensity with the thickness, and the annihilation rate suggest that the energy of almost all the positrons passed through the metal foils was much above the positronium formation threshold of 9 eV. Total thickness of 0.1 g cm-2 of the moderator and the Ar gas was required to stop almost all the positron in Ar gas.
Contribution to the Topical Issue “Electron and Positron Induced Processes”, edited by Michael Brunger, Radu Campeanu, Masamitsu Hoshino, Oddur Ingólfsson, Paulo Limão-Vieira, Nigel Mason, Yasuyuki Nagashima and Hajime Tanuma.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2014
