Positron accumulation in the GBAR experiment
Philipp Blumer, M. Charlton, М. Chung, Pierre Cladé, P. Comini, P. Crivelli, O. D. Dalkarov, P. Debu, L. Dodd, A. Douillet, S. Guellati, Paul-Antoine Hervieux, Laurent Hilico, A. Husson, P. Indelicato, Gianluca Janka, S. Jonsell, Jean‐Philippe Karr, B. H. Kim, E.S. Kim, S.K. Kim, Y. Ko, Tymoteusz Kosiński, N. Kuroda, B. M. Latacz, B. Lee, Hyung Mok Lee, J. S. H. Lee, A.M.M. Leite, K. Lévêque, E. Lim, L. Liszkay, P. Lotrus, D. Lunney, Giovanni Manfredi, B. Mansoulié, M. Matusiak, G. Mornacchi, V. V. Nesvizhevsky, F. Nez, S. Niang, Ryosuke Nishi, Ben Ohayon, K. Park, N. Paul, P. Pérez, S. Procureur, B. Radics, C. Regenfus, J.-M. Reymond, Serge Reynaud, J.-Y. Roussé, Olivier Rousselle, A. Rubbia, J. Rzadkiewicz, Y. Sacquin, F. Schmidt–Kaler, M. Staszczak, K. Szymczyk, T. Tanaka, B. Tuchming, B. Vallage, A. Yu. Voronin, D. P. van der Werf, S. Wolf, D. Won, S. Wronka, Y. Yamazaki, K.H. Yoo, P. Yzombard, Chris Baker
Abstract
We present a description of the GBAR positron (e+) trapping apparatus, which consists of a three stage Buffer Gas Trap (BGT) followed by a High Field Penning Trap (HFT), and discuss its performance. The overall goal of the GBAR experiment is to measure the acceleration of the neutral antihydrogen (H¯) atom in the terrestrial gravitational field by neutralising a positive antihydrogen ion (H¯+), which has been cooled to a low temperature, and observing the subsequent H¯ annihilation following free fall. To produce one H¯+ ion, about 1010 positrons, efficiently converted into positronium (Ps), together with about 107 antiprotons (p¯), are required. The positrons, produced from an electron linac-based system, are accumulated first in the BGT whereafter they are stacked in the ultra-high vacuum HFT, where we have been able to trap 1.4(2) × 109 positrons in 1100 s.