Orateur
Description
The observed matter–antimatter asymmetry in the Universe remains one of the major open questions in modern physics. The Matter’s Origin from RadioActivity experiment (MORA) aims to answer this question by searching for CP violation by measuring the so-called D correlation parameter from nuclear beta decay. This parameter is sensitive to time-reversal symmetry violation and therefore to CP violation via the CPT theorem.The D correlation is the triple correlation between the nuclear spin and the decay product momenta (the positron/electron and the neutrino/antineutrino) and is accessed experimentally through measuring an angular asymmetry between recoil ions (instead of the neutrino/antineutrino) and the charged leptons in the plane perpendicular to the nuclear spin.
For the detection of these products, MORA has 4 phoswich detectors to detect the beta particles and 4 MCP based recoil ion detectors. This poster will present the energy calibration of the phoswich detectors, which is essential for setting a unique energy threshold for all detectors so that we do not create a fake D correlation, and also to test the theoretical values of the final state interactions, which depend on the energy of the emitted beta. MORA will be sensitive to such effects in the future when it moves to DESIR, where a sensitivity of 10⁻⁵ will be reached.
The phoswich detector is made of a fast thin scintillator and a slow thick one, enabling the discrimination between emitted betas and gammas. This adds complexity to the calibration process since the signals are correlated and each layer has a different gain.