Use of pixel detectors in elementary particle physics

Abstract Silicon pixel detectors allow measurement of charm and bottom decays, which have mean rest-frame decay lengths in the range 60–360 μm. Because of the high particle density which can be accommodated by detectors with pixel size 30 μm × 30 μm, direct measurement of decay paths should be possible in future fixed-target experiments. At high energy hadron colliders like the SSC and LHC and at e + e − colliders operating at the Z 0 resonance the two particle separation will be of order 70 μm at the inner barrel. Such a high track density can best be accommodated with pixel detectors. A prototype readout chip for a pixel detector has been submitted for fabrication by an SSC R&D collaboration. This chip contains a random access array of 32 × 64 cells of dimension 45 × 150 μm. Each cell has analog and digital storage. The performance goal is 300 electrons rms noise at 20°C and full charge collection in 50 ns.