SPACE RESOLUTION OF A SILICON PIXEL DETECTOR AS A FUNCTION OF THE TRACK ANGLE

We measured the spatial resolution of a 300 mu m thick 75 x 500 mu m s ilicon pixel detector as a function of the track angle using a 120 GeV pion beam. We observed that 13% of tracks perpendicular to the detect or give a signal on two neighboring pixels; this fraction increases to 50% at an angle of 15 degrees w.r.t. the normal incidence direction. The average spatial resolution is 28.2 mu m at 0 degrees and 14.6 mu m at 15 degrees. The detector efficiency is not affected by the charge sharing between pixels. Our data agree with the predictions of a simpl e geometrical model describing the charge sharing in the region betwee n pixels. This model can be the basis for a full simulation of the beh aviour of a pixel detector.