The DIRC particle identification system for the BaBar experiment

Abstract A new type of ring-imaging Cherenkov detector is being used for hadronic particle identification in the B a B ar experiment at the SLAC B Factory (PEP-II). This detector is called DIRC, an acronym for Detection of Internally Reflected Cherenkov (Light). This paper will discuss the construction, operation and performance of the B a B ar DIRC in detail.