The Barrel DIRC (Detection of Internally Reflected Cherenkov light) detector will be an essential part of the hadronic PID system of the PANDA experiment at GSI, Darmstadt. Covering the polar angle range of 22-140 degrees, it will provide pion-kaon separation power of at least 3 standard deviations for a charge particle momenta between 0.5 GeV/c and 3.5 GeV/c.
The design of the Barrel DIRC features the narrow bar radiator made from synthetic fused silica, a complex multi-layer spherical lens focusing system, a prism-shaped fused silica expansion volume, and MCP-PMTs (MicroChannel-Plate PhotoMultiplier Tubes) to detect the location and arrival time of the Cherenkov photons. All components were tested and successfully validated with a sophisticated prototype in a mixed hadron particle beam at CERN during 2015-2017. Additional test was conducted at CERN in 2018 with a purpose to optimize the number of used MCP-PMTs. Result of the optimization with the analysis and a comparison to the Geant4 simulation will be presented.