Professor Tony Weidberg

Abstract:

A radiation hard optical readout system designed for the ATLAS Semiconductor Tracker (SCT) is described. Two independent versions of the front-end optical package housing two VCSEL emitters and an epitaxial Si PIN photodiode have been irradiated with neutron fluences over 10(15) n cm(-2), the level encountered in the ATLAS pixel detector. Environmental tests have been performed down to -20 degreesC. Extensive radiation and lifetime tests have also been carried out on the opto-electronic components and the front-end VCSEL driver and timing/ control ASICs. Bit error rate, cross-talk and single event upset measurements using irradiated devices show that the system meets the performance specification.

Abstract:

The ATLAS SCT optical links system is reviewed. The assembly and testing of prototype opto-hamesses are described. Results are also given from a system test of the SCT barrel modules, including optical readout.

Abstract:

A prototype optical data and Timing, Trigger and Control transmission system based on LEDs and PIN-diodes has been constructed. The system would be suitable in terms of radiation hardness and radiation length for use in the ATLAS SemiConductor Tracker. Bit error rate measurements were performed for the data links and for the links distributing the Timing, Trigger and Control data from the counting room to the front-end modules. The effects of cross-talk between the emitters and receivers were investigated. The advantages of using Vertical Cavity Surface Emitting Lasers (VCSELs) instead of LEDs are discussed.