Performance of the MORA apparatus for testing time-reversal invariance in nuclear beta decay

The MORA experimental setup is designed to measure the triple-correlation \(D\) parameter in the nuclear beta decay of trapped and polarized \(^{23}\)Mg\(^+\) and \(^{39}\)Ca\(^+\) ions. The \(D\) coefficient is sensitive to potential violations of time-reversal invariance – and, via the CPT theorem, to CP violation. The experimental configuration consists of a transparent Paul trap surrounded by a detection setup with alternating \(\beta \) and recoil-ion detectors. The octagonal symmetry of the detection setup optimizes the sensitivity of positron-recoil-ion coincidence rates to the \(D\) correlation, while reducing systematic effects. MORA utilizes an innovative in-trap laser polarization technique. The design and performance of the ion trap and associated optics, lasers and \(\beta \) and detection system are presented. The recent experimental demonstration of the polarization technique is described.