  In this article we explore the angular resolution limits attainable in small
FDIRC designs taking advantage of the new highly pixelated detectors that are
now available. Since the basic FDIRC design concept attains its particle
separation performance mostly in the angular domain as measured by
two-dimensional pixels, this paper relies primarily on a pixel-based analysis,
with additional chromatic corrections using the time domain, requiring single
photon timing resolution at a level of 100-200ps only. This approach differs
from other modern DIRC design concepts such as TOP or TORCH detectors, whose
separation performances rely more strongly on time-dependent analyses. We find
excellent single photon resolution with a geometry where individual bars are
coupled to a single plate, which is coupled in turn to a cylindrical lens
focusing camera.
