  A novel modular high-resolution charged-particle tracking detector design
using $250\mu m$ diameter, round, scintillating fibers and SiPM arrays for
readout is presented. The fiber modules consist of 8 layers of 128 fibers,
mechanically sta bilized by a carbon fiber / Rohacell foam structure. A
prototype using scintillating fibers with a diameter of $300\mu m$ and two typ
es of silicon photomultipliers has been tested in a $10GeV$ proton beam in late
October 2006 at the T9 PS-beamline, CERN. We present the measured spatial
resolu tion, efficiency and signal-over-noise for this setup. The advantage of
this tra cker concept is a compact and modular design with low material budget
and only little or no cooling requirements depending on the quality of the
silicon photomultiplieres.
