Two-Symmetry Penning-Ioffe Trap for Antihydrogen Cooling and Spectroscopy

High-accuracy spectroscopic comparisons of trapped antihydrogen atoms ($overline{text{H}}$) and hydrogen atoms ($text{H}$) promise to stringently test the fundamental CPT symmetry invariance of the standard model of particle physics. ATRAPs nested Penning-Ioffe trap was developed for such studies. The first of its unique features is that its magnetic Ioffe trap for $overline{text{H}}$ atoms can be switched between quadrupole and octupole symmetries. The second is that it allows laser and microwave access perpendicular to the central axis of the traps.