The large-area hybrid-optics CLAS12 RICH: Assembling, commissioning and first data-taking

Abstract The first module of a Ring Imaging Cherenkov detector has been recently installed on the CLAS12 spectrometer at the Jefferson Laboratory (JLab) to provide the experiment with kaon identification in the momentum range between 3 and 8 GeV/c. The detector adopts a hybrid optics solution with aerogel radiator, light planar and spherical mirrors and highly-segmented photon detectors. We report here on the assembly and installation of the RICH and we show the first preliminary results obtained during the commissioning of the detector and the first physics data taking.