  A tracking detector based on two meters long scintillating fibers read out by
silicon photomultipliers (SiPM) is being developed for the Kaos spectrometer at
the Mainz Microtron MAMI. Results from a prototype setup using 2 mm square
fibers and large area SiPM readout are presented. The detection efficiency of
such a combination was measured to be between 83 and 100% depending on the
threshold on the SiPM amplitude. A Monte Carlo simulation based on a physical
model was employed in order to extract the photon detection efficiency of the
SiPM devices.
