High Efficiency Cyclotron Trap Assisted Positron Moderator
Lars Gerchow,
Saverio Braccini,
Tommaso Stefano Carzaniga,
David Cooke,
Max Döbeli,
Klaus Kirch,
Ulli Köster,
Arnold Müller,
Nicholas P. van der Meulen,
Christiaan Vermeulen,
André Rubbia,
Paolo Crivelli
Affiliations
Lars Gerchow
Institute for Particle Physics, ETH Zurich, Otto-Stern Weg 5, CH-8093 Zurich, Switzerland
Saverio Braccini
Albert Einstein Center for Fundamental Physics (AEC), Laboratory for High Energy Physics (LHEP), University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
Tommaso Stefano Carzaniga
Albert Einstein Center for Fundamental Physics (AEC), Laboratory for High Energy Physics (LHEP), University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland
David Cooke
Institute for Particle Physics, ETH Zurich, Otto-Stern Weg 5, CH-8093 Zurich, Switzerland
Max Döbeli
Institute for Particle Physics, ETH Zurich, Otto-Stern Weg 5, CH-8093 Zurich, Switzerland
Klaus Kirch
Institute for Particle Physics, ETH Zurich, Otto-Stern Weg 5, CH-8093 Zurich, Switzerland
Ulli Köster
Institut Laue Langevin, 6 rue Jules Horowitz, F-38042 Grenoble CEDEX 9, France
Arnold Müller
Institute for Particle Physics, ETH Zurich, Otto-Stern Weg 5, CH-8093 Zurich, Switzerland
Nicholas P. van der Meulen
Paul Scherrer Institute, CH-5232 Villigen, Switzerland
Christiaan Vermeulen
Los Alamos National Laboratory, Los Alamos, NM 87545, USA
André Rubbia
Institute for Particle Physics, ETH Zurich, Otto-Stern Weg 5, CH-8093 Zurich, Switzerland
Paolo Crivelli
Institute for Particle Physics, ETH Zurich, Otto-Stern Weg 5, CH-8093 Zurich, Switzerland
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.
