The RICH detector of the CBM experiment

The CBM-RICH detector is designed to identify electrons with momenta up to 8 GeV/c and high purity as this is essential for the CBM physics program. The detector consist of a CO2-gaseous radiator, a spherical mirror system, and Multi-Anode PhotoMultiplier Tubes (MAPMT) of type H12700 from Hamamatsu as photon detectors. The detector concept was verified through R&D studies and a laterally scaled prototype. The results were summarized in a TDR, in which open issues were defined concerning the readout electronics, the shielding of the magnetic stray field in the MAPMT region, the radiation hardness of the MAPMT sensors, and the mechanical holding structure of the mirror system. In this article an overview is given on the CBM RICH development with focus on those open issues.