Measuring the Properties of Antihydrogen

This thesis describes the latest results of the on-going efforts to mea- sure the properties of antihydrogen within the ALPHA collaboration. More specifically, it covers the construction and commissioning of the ALPHA-g experiment [ 1 ], and the plans to measure how antimatter behaves in Earth’s gravitational field. A special emphasis is on the ALPHA-g magnet system used to confine and manipulate the anti- hydrogen atoms. Tests of methods for calculating magnetic fields relevant for simulations [ 2 ] are covered as well. Amongst the described results from the ALPHA-2 experiment is the characterisation of the fine structure of antihydrogen [ 3 ]. The combined result of the mea- sured 1S–2P 1/2 and 1S–2P 3/2 transitions agrees with the prediction of quantum electrodynamics to 16 parts per billion. The thesis also describes the demonstration of the first laser cooling of antimatter [ 4 ], which paves the way for a measurement of the 1S–2S transition in antihydrogen with hydrogen-like precision, and a measurement of antigravity with 1% precision. Both are future goals of the ALPHA collaboration.