  Most of the time-of-flight systems as well as the fast interaction trigger
detectors have large surfaces and the principal requirements for the above
mentioned detectors is a good time resolution of the order 100-200ps. The
easiest solution here is to split the large surface into the small tiles with a
read-out directly attached to the photo-sensor. This solution is expensive
because the number of the channels grows proportional to the surface. Although
if the coverage of the whole surface by the sensors is not sufficient, one can
obtain non uniform response, which is not acceptable if uniformity is required.
Our suggestion is based on the usage of clear fibres mounted perpendicular on
the surface of the scintillator as a matrix providing uniform surface reduction
and keeping most of the benefices of the small tiles with the photo-sensors. In
this work the design and some analytic estimations of the light collection
efficiency for direct and reflected photons will be presented. Also some simple
estimations are presented for the time-spread and for the light pulse wave form
dependent on the lateral sizes and the thickness of the scintillator.
