  FastDIRC is a novel fast Monte Carlo and reconstruction algorithm for DIRC
detectors. A DIRC employs rectangular fused-silica bars both as Cherenkov
radiators and as light guides. Cherenkov-photon imaging and time-of-propagation
information are utilized by a DIRC to identify charged particles. GEANT-based
DIRC Monte Carlo simulations are extremely CPU intensive. The FastDIRC
algorithm permits fully simulating a DIRC detector more than 10000 times faster
than using GEANT. This facilitates designing a DIRC-reconstruction algorithm
that improves the Cherenkov-angle resolution of a DIRC detector by about 30%
compared to existing algorithms. FastDIRC also greatly reduces the time
required to study competing DIRC-detector designs.
