A HYBRID SILICON PIXEL TELESCOPE TESTED IN A HEAVY-ION EXPERIMENT

Specific features of the OMEGA-ION pixel detector are the adjustable delay with external trigger capability and the detector leakage current compensation. A row of pixels can be used for testing the electrical performance of the amplifier and comparator circuits. Detailed results of these electrical tests are presented. A telescope made of three OMEGA-ION hybrid silicon pixel detectors has been successfully tested in the heavy-ion experiment WA94. Each plane consisted of a single detector with 1006 active pixels (500 mum x 75 mum), each one being bump-bonded to the readout chip, and arranged in 16 columns and 63 rows respectively. With a sensitive area as small as 8000 x 4725 mu m2 several million events with at least one track originating from the sulphur-sulphur interaction have been recorded in a few hours. Results on target reconstruction, tracking accuracy and efficiency are presented.