Professor Tony Weidberg

Abstract:

ATLAS (The ATLAS Technical Proposal, CERN/LHCC 94-33) is one of the large electronic particle detectors at LHC (The LHC Conceptual Design, Report- The Yellow Book, CERN/AC/95-05(LHC)) which will become operational in 2005. It is planned to use radiation tolerant optical links for the data transfer from the SemiConductor Tracker (SCT) (ATLAS Inner Detector Technical Proposal, CERN/LHCC 97-16 & CERN/LHCC 97-17). and Pixel Detector (ATLAS Pixel Detector Technical Proposal, CERN/LHCC 98-13) systems to the acquisition electronics over a distance up to 140m. The overall architecture and the performance of these optical data links are described. One of the three candidate designs for an on-detector Opto-Package is presented. (C) 2001 Published by Elsevier Science B.V.

Abstract:

ATLAS (The ATLAS Technical Proposal, CERN/LHCC 94-33) is one of the large electronic particle detectors at LHC (The LHC Conceptual Design, Report- The Yellow Book, CERN/AC/95-05(LHC)) which will become operational in 2005. It is planned to use radiation tolerant optical links for the data transfer from the SemiConductor Tracker (SCT) (ATLAS Inner Detector Technical Proposal, CERN/LHCC 97-16 & CERN/LHCC 97-17). and Pixel Detector (ATLAS Pixel Detector Technical Proposal, CERN/LHCC 98-13) systems to the acquisition electronics over a distance up to 140m. The overall architecture and the performance of these optical data links are described. One of the three candidate designs for an on-detector Opto-Package is presented. © 2001 Published by Elsevier Science B.V.

Abstract:

A large sample (96) of epitaxial Si PIN photodiodes has been irradiated by approximately 1 MeV neutrons and 24 GeV protons with fluences up to 10¹⁵ equivalent 1 MeV neutrons cm^-2 in order to test their suitability for use in the optical readout of the ATLAS semiconductor tracker and pixel detector at the CERN Large Hadron Collider. After an initial reduction of 30% the responsivity remains constant up to the maximum fluence. The rise and fall times are not significantly affected and remain below 1 ns. Although the dark current increases linearly with increasing neutron fluence, its level remains below 100 nA which is negligible in comparison to the operating photocurrent which is above 100 μA. Enhanced ageing studies at 60 °C have also been carried out and no failure has occurred after an equivalent of 360 years of operation.

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.