  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
10^10 positrons, efficiently converted into positronium (Ps), together with
about 10^7 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) x 10^9 positrons in 1100 seconds.
