The SuperNEMO Demonstrator calorimeter commissioning

International audienceThe SuperNEMO experiment aims to search for 0$\nu \beta \beta$: this discovery would prove the Majorana nature of neutrinos. The final detector goal is to reach a sensitivity of $10^{26}$ years on the 0$\nu \beta \beta$ decay half-life, i.e an effective Majorana neutrino mass of 50 - 100 meV. The first module of the SuperNEMO experiment is under installation at Laboratoire Souterrain de Modane (LSM), with 6.23 kg of Se82. Electrons from disintegrations are tracked when crossing the wire chamber, then their energies and arrival times are measured by the calorimeter. The calorimeter is composed of 712 optical modules, an assembly of large volume plastic scintillators couples to PMTs. The commissioning of the SuperNEMO calorimeter began in 2019. An optimised parameterisation of the PMT signal waveforms has been developed. The calorimeter response has been calibrated in energy using the internal Tl208 spectrum, and photomultipliers' gains were equalised at 1 MeV with < 10$\%$ spread over all the calorimeter walls. A Co60 source, emitting two gammas simultaneously, was used to generate preliminary measurements of the time resolution of all optical modules of \\< 600 ps at 1 MeV