Machines and methods for trapping antihydrogen

A new generation of antihydrogen experiments was designed built and commissioned for use by the ATRAP collaboration at the European Center for Nuclear Research (CERN) to further progress towards the long term goal of antihydrogen laser spectroscopy. A comparison of the 1S-2S transition in hydrogen and antihydrogen would be the best test of CPT invariance in a combined lepton-baryon system. Cold antihydrogen was first produced in 2002 but a new set of experiments incorporating a magnetic field minimum Ioffe trap had to be undertaken in order to confine antihydrogen long enough to conduct precise measurements. Two new experimental zones and two new Penning-Ioffe trap apparatuses were constructed to conduct these experiments. New particle loading methods for antiprotons, electrons and positrons were implemented yielding far higher loading rates. Experiments were conducted at a lower field compatible with a Ioffe trap than previous experiments. The stability of charged particles and the formation of antihydrogen atoms in a combined 375 mK deep quadrupole Penning-Ioffe trap configuration was demonstrated resolving a several year long debate over whether this would be possible, but no trapped antihydrogen atoms have been detected yet. The first resonant detection of single antiprotons in an apparatus capable of producing antihydrogen was achieved, paving the way for searches for antihydrogen ions and sensitive detection calibrations. The temperature of the electrodes surrounding the particles was brought down to 1.2 K greatly improving the prospects for trapping antihydrogen. Preliminary work towards a next generation apparatus to be commissioned in late 2009 or 2010 was undertaken.