Positron production using a 9 MeV electron linac for the GBAR experiment

M. Charlton , J.J. Choi , M. Chung , P. Cladé (1) , P. Comini (2) , P.P. Crépin (1) , P. Crivelli , O. Dalkarov , P. Debu (2) , L. Dodd , A. Douillet (1, 3) , Saïda Guellati-Khélifa (1) , P.A. Hervieux (4) , L. Hilico (1) , A. Husson (5) , P. Indelicato (1) , G. Janka , S. Jonsell , J-P Karr (1) , B.H. Kim , E-S. Kim , S.K. Kim , Y. Ko , T. Kosinski , N. Kuroda , B. Latacz (2) , H. Lee , J. Lee , A.M.M. Leite (2) , K. Lévêque (4) , E. Lim , L. Liszkay (2) , P. Lotrus (2) , T. Louvradoux (1) , D. Lunney (5) , G. Manfredi (4) , B. Mansoulié (2) , M. Matusiak , G. Mornacchi , V.V. Nesvizhevsky (6) , F. Nez (1) , S. Niang (2) , R. Nishi , S. Nourbaksh , K.H. Park , N. Paul (1) , P. Pérez (2) , S. Procureur (2) , B. Radics , C. Regenfus , J.M. Rey (2) , J.M. Reymond (2) , S. Reynaud (1) , J.Y. Roussé (2) , O. Rousselle (1) , A. Rubbia , J. Rzadkiewicz , Y. Sacquin (2) , F. Schmidt-Kaler , M. Staszczak , B. Tuchming (2) , B. Vallage (2) , A. Voronin , A. Welker , D.P. van Der Werf , S. Wolf , D. Won , S. Wronka , Y. Yamazaki , K.H. Yoo

1 LKB [Collège de France] - Laboratoire Kastler Brossel
2 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
3 CEA - Commissariat à l'énergie atomique et aux énergies alternatives
4 IPCMS - Institut de Physique et Chimie des Matériaux de Strasbourg
5 IJCLab - Laboratoire de Physique des 2 Infinis Irène Joliot-Curie
6 ILL - Institut Laue-Langevin

For the GBAR (Gravitational Behaviour of Antihydrogen at Rest) experiment at CERN’s Antiproton Decelerator (AD) facility we have constructed a source of slow positrons, which uses a low-energy electron linear accelerator (linac). The driver linac produces electrons of 9 MeV kinetic energy that create positrons from bremsstrahlung-induced pair production. Staying below 10 MeV ensures no persistent radioactive activation in the target zone and that the radiation level outside the biological shield is safe for public access. An annealed tungsten-mesh assembly placed directly behind the target acts as a positron moderator. The system produces 5×107 slow positrons per second, a performance demonstrating that a low-energy electron linac is a superior choice over positron-emitting radioactive sources for high positron flux.

Mots clés: positron; linear accelerator; antimatter; antihydrogen; gravitation 2; Positron; Linear accelerator; Antimatter; Antihydrogen; Gravitation; electron: linear accelerator; positron: particle source; positron: yield; energy: low; radioactivity; electron: pair production; gravitation: acceleration; performance; CERN Lab; tungsten; safety

Domaines: Instrumentations et Détecteurs [physics.ins-det]

M. Charlton, J.J. Choi, M. Chung, P. Cladé, P. Comini, et al.. Positron production using a 9 MeV electron linac for the GBAR experiment. Nucl.Instrum.Meth.A, 2021, 985, pp.164657. ⟨10.1016/j.nima.2020.164657⟩. ⟨hal-02899244⟩