The LHCb Ring-Imaging Cherenkov (RICH) system is essential for Particle Identification (PID) of charged hadrons in the momentum range 2–100 GeV/c: it consists of an upstream detector (RICH 1), located close to the interaction point, and a downstream detector (RICH 2), placed after the tracking system. The LHCb experiment has been upgraded to deal with a five-fold increase in instantaneous luminosity, up to $2 \times 10^{33}\; cm^{-2}\; s^{-1}$, and to read out data at a rate of 40 MHz during RUN3. Both RICH detectors have been upgraded to maintain and excellent PID with a redesigned opto-electronic chain and new photon detectors. In addition, RICH 1 has a modified layout with new mechanics and spherical mirrors to reduce the maximum occupancy. The RICH system has taken part in all stable beams collisions throughout 2022. The RICH detectors are currently fully functional, time aligned, and integrated into the run control with all the other LHCb sub-detectors. The first data taken in the nominal RUN3 conditions seem promising and preliminary studies show an improved or equal PID performance compared to the one achieved in RUN2. An overview of the LHCb RICH system commissioning campaign is given, following all the steps from the first quality assurance measurements up to the current status of the detectors in the LHCb cavern
The two LHCb Ring Imaging Cherenkov detectors, providing charged hadron discrimination, underwent a major upgrade to withstand with the five-fold increase in the instantaneous luminosity delivered to the experiment in Run 3. The opto-electronics chain has been completely changed by employing approximately 3100 Multianode Photomultiplier Tubes and a brand-new frontend electronics. The number of detected Cherenkov photons per track is one of the crucial parameters driving the charged hadron identification performance and therefore the sensitivity to single photons at rates up to 100 MHz/cm2 is of paramount importance. In order to uniformy the response of the detectors and to maximise the efficiency, the calibration data acquired in the experiment has been used to equalise the single photon gain over approximately 200k channels by keeping at the same time the backgrounds under control. The data-taking procedures, data analysis techniques and the results of the calibration are presented.