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Open AccessFeature PaperArticle

High Efficiency Cyclotron Trap Assisted Positron Moderator

Institute for Particle Physics, ETH Zurich, Otto-Stern Weg 5, CH-8093 Zurich, Switzerland
Albert Einstein Center for Fundamental Physics (AEC), Laboratory for High Energy Physics (LHEP), University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
Paul Scherrer Institute, CH-5232 Villigen, Switzerland
Institut Laue Langevin, 6 rue Jules Horowitz, F-38042 Grenoble CEDEX 9, France
Los Alamos National Laboratory, Los Alamos, NM 87545, USA
Author to whom correspondence should be addressed.
Instruments 2018, 2(3), 10;
Received: 16 May 2018 / Revised: 31 May 2018 / Accepted: 25 June 2018 / Published: 28 June 2018
PDF [1107 KB, uploaded 28 June 2018]


We report on the realisation of a cyclotron trap assisted positron tungsten moderator for the conversion of positrons with a broad keV–few MeV energy spectrum to a mono-energetic eV beam with an efficiency of 1.8(2)% defined as the ratio of the slow positrons divided by the β+ activity of the radioactive source. This is an improvement of almost two orders of magnitude compared to the state of the art of tungsten moderators. The simulation validated with this measurement suggests that, using an optimised setup, even higher efficiencies are achievable. A novel method for the production of 48V high-activity thin foil positron sources based on a solid target station at a medical cyclotron was developed. This is an improvement of more than one order of magnitude with respect to standard methods. View Full-Text
Keywords: positron; moderation; moderation efficiency; moderator; cyclotron trap; magnetic bottle; thin film source positron; moderation; moderation efficiency; moderator; cyclotron trap; magnetic bottle; thin film source

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Gerchow, L.; Braccini, S.; Carzaniga, T.S.; Cooke, D.; Döbeli, M.; Kirch, K.; Köster, U.; Müller, A.; Van der Meulen, N.P.; Vermeulen, C.; Rubbia, A.; Crivelli, P. High Efficiency Cyclotron Trap Assisted Positron Moderator. Instruments 2018, 2, 10.

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