CALIOPE: A Test of CPT-invariance in o-Ps Decay

We propose a test of CPT-invariance in ortho-positronium (o-Ps) decays with CALIOPE, or CP(T) Aberrant Leptons in o-Ps Experiment. CPT-violation could manifest itself in angular cor- relations between the directions of the three gamma rays emitted in the decay of o-Ps. We use an array that provides 75\% of 4$\pi$ angular acceptance, increasing our statistics over previous such experiments. The array is composed of 24 NaI(Tl) bars arranged cylindrically. A cylinder of aero- gel adjacent to a tagged source supplies positronium at the center of the array. We will present a systematics study and the first detection of o-Ps. A search for CP-violation is also possible with the addition of an electromagnet.