Status report on the GBAR CERN experiment

6th Symposium on Large TPCs for Low Energy Rare Event Detection

Debu, Pascal^1

Irfu, CEA Saclay, 91191 Gif-sur-Yvette CEDEX, France^1

关键词: Antihydrogen atoms;    Experimental techniques;    Gravitational accelerations;    Photo-detachment;    Positronium formation;    Sympathetic cooling;    Ultracold atoms;    Weak equivalence principle;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/460/1/012008/pdf
DOI  :  10.1088/1742-6596/460/1/012008

来源: IOP

【 摘 要 】

GBAR is a recently approved experiment at CERN/AD. Its aim is to perform the first test of the Weak Equivalence Principle with Antimatter. The objective is to measure the gravitational acceleration of antihydrogen atoms on Earth with 1% precision in a first phase, and better than a per mil in a second phase. The method is to detect the free fall of ultra-cold atoms. By sympathetic cooling of antihydrogen positive ions+with beryllium ions, and after photodetachment of the excess positron, antiatoms are formed at m/s velocities and their free fall can be directly measured. Antihydrogen ions are produced by the interaction of keV antiprotons with a dense positronium cloud, the latter being formed by dumping positrons onto a porous material. We describe here briefly the experimental techniques and report on the most recent results. In particular, a flux of around 4 × 106e+s-1slow positrons is now produced by the source installed at Saclay, cross sections for the production of the+ions have been computed, and a dedicated beam line for the study of positronium formation and for applications in Materials Science has been realized. The tentative schedule of the GBAR developments is given.