Abstract
The PANDA experiment at FAIR near Darmstadt, Germany, is under construction, planned to investigate fundamental questions of hadron physics with a fixed proton target by using an antiproton beam within a momentum range of 1.5 to 15 GeV/c. A novel Cherenkov detector, the Endcap Disc DIRC (EDD), has been developed to separate π± and K± by at least 3 standard deviation up to 4 GeV/c. It will cover the polar angle range of the forward endcap of the PANDA target spectrometer from 5o to 22o. The EDD uses a 2 cm thick fused silica radiator plate with focusing elements at the outer rim and lifetime-enhanced Microchannel-Plate PMTs (MCP-PMTs) as light sensors. The Cherenkov radiator of the EDD consists of four identical independent quadrants, polished with highest precision in order to conserve the internally reflected Cherenkov angle during light propagation. This manuscript confirms basic functionalities of the EDD design and tests of the prototype with particle beams at CERN in 2018.