The CLAS12 Ring Imaging Cherenkov detector

A ring imaging Cherenkov (RICH) detector has been installed in the CLAS12 spectrometer at Jefferson Laboratory (JLab) to provide kaon identification in the momentum range between 3 GeV/c 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 design, construction, and initial performance of the RICH during the commissioning of the detector and the first physics data taking period. •A novel large-area hybrid-optics RICH detector has been realized.•Hadron separation has been achieved in the challenging 3 to 8 GeV/c momentum range.•Composite aeronautic materials has been exploited to get a light and stiff structure.•Light glass-skin planar mirrors have been introduced in a high-energy experiment.•Unprecedented transmittance for n=1.05 hydrophilic aerogel has been achieved.