Record accumulation of antiprotons in a Penning-Malmberg Trap and their preparation for improved production of antihydrogen beams

TL;DR

This paper reports on the successful accumulation and trapping of antiprotons in a Penning-Malmberg trap, significantly increasing the number of antiprotons available for antihydrogen production and improving experimental capabilities.

Contribution

It introduces a new trapping scheme that enhances antiproton accumulation and reduces emittance growth, enabling more efficient antihydrogen beam production.

Findings

Trapped 56% of the ELENA beam

Delivered 6.4 million antiprotons per shot

Accumulated over 64 million antiprotons in 35 minutes

Abstract

CERN's AD/ELENA ``antimatter factory'' - unique worldwide - serves several experiments, all of which use electromagnetic traps to accumulate antiprotons for fundamental science. The GBAR experiment employs a charge-exchange reaction between an antiproton beam and a positronium cloud to produce antihydrogen for gravitational studies. GBAR has also pioneered an electrostatic scheme using a pulsed drift tube to decelerate the 100 keV antiproton beam, rather than slowing the antiprotons in a foil, as is commonly done in other experiments. Following first results producing a 6 keV antihydrogen beam directly after the decelerator, a trap has now been installed to increase the production rate. The emittance growth resulting from the deceleration is reduced in the trap by Coulomb interaction with a cold electron cloud. The antiproton cloud is further compressed using rotating wall cooling and can be re-accelerated up to energies of 10 keV, including a time focus. Here we describe the commissioning results, trapping 56(3)\% of the ELENA beam, delivering $6.4(0.4)~\times~10^{6}$ antiprotons per shot for improved production of antihydrogen, and a record accumulation of over $6.4(0.4)~\times~10^{7}$ antiprotons in under 35 minutes.