https://doi.org/10.1140/epja/s10050-025-01694-3
Regular Article - Experimental Physics
Performance of the MORA apparatus for testing time-reversal invariance in nuclear beta decay
1
GANIL, CEA/DRF-CNRS/IN2P3, Bd H. Becquerel, 14076, Caen, France
2
Université de Caen Normandie, ENSICAEN, CNRS/IN2P3, LPC Caen UMR6534, 14000, Caen, France
3
University of Jyväskylä, Department of Physics, Accelerator Laboratory, P.O. Box 35(YFL), 40014, Jyväskylä, Finland
4
Instituut voor Kern- en Stralingsfysica, KU Leuven, 3001, Leuven, Belgium
5
IJCLab, 15 Rue Georges Clemenceau, 91400, Orsay, France
6
Instituto de Física Corpuscular (IFIC), CSIC-UV, E-46980, Paterna (Valéncia), Spain
7
Synchrotron SOLEIL, 91190, Saint-Aubin, France
8
ASNR/LMRE, Rue du Belvédère, 91400, Orsay, France
Received:
22
May
2025
Accepted:
11
September
2025
Published online:
1
October
2025
The MORA experimental setup is designed to measure the triple-correlation 
parameter in the nuclear beta decay of trapped and polarized 
Mg
and 
Ca ions. The 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 
and recoil-ion detectors. The octagonal symmetry of the detection setup optimizes the sensitivity of positron-recoil-ion coincidence rates to the 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 and detection system are presented. The recent experimental demonstration of the polarization technique is described.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2025
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
