Antihydrogen gravity Apparatus

ALPHA first measured the gravitational mass of antihydrogen atoms in a magnetic minimum trap in 2013, limiting anomalous forces coupled to the antiatoms to <75 times of gravity. A new apparatus is being designed to tighten the limit to much better than order unity. It entails a magnetic trap with a vertical long axis and maximal height to improve gravity signal. The magnets creating the trap are designed to ensure a magnetic up-down asymmetry <1e-5 T, a level of field control achieved by taking into account the effect of fabrication error, the inter-connections between current loops, the current leads into/out of the magnets, wire splices, and other fine, uncontrolled details inside the superconducting wires.