High level performance of the RICH detector of the NA62 experiment at CERN during run 2 data taking

After the run 1 data taking of NA62 (2014-2018), the RICH detector has been successfully operated during the beginning of run 2 in 2021 and 2022, being essential in most of the NA62 analyses. The main design aspects and operational characteristics of the detector will be described and a detailed report of its high level performance concerning the $\pi / \mu$ separation, directly measured with the data collected in 2022, will be presented in comparison to the run 1 results, in order to asses the effect of the detector aging. To this purpose the time dependence of the basic performance of the RICH will also be presented. Furthermore, new analysis techniques, to improve the knowledge of the RICH behaviour (mirror reflectivity, PM efficiency), will be presented.