Professor Tony Weidberg

Abstract:

The fibres used for the readout of the upgraded LHC detectors for the High Luminosity Large Hadron Collider (HL-LHC) will be exposed to very high radiation doses of up to ∼ 500 kGy(Si). From DC measurements of the radiation induced absorption, several singlemode (SM) and multimode (MM) fibres have been qualified. The effect of radiation damage on fibres is also expected to have an adverse impact on the fibre bandwidth. This paper explains the theoretical reasons for this and presents results of extensive tests to determine the significance of this effect for one of the previously qualified radiation-hard multi-mode fibres. © 2012 IOP Publishing Ltd and Sissa Medialab srl.

Abstract:

© 2012 CERN. Published by Elsevier B.V. A search for the Standard Model Higgs boson in proton-proton collisions with the ATLAS detector at the LHC is presented. The datasets used correspond to integrated luminosities of approximately 4.8 fb -1 collected at √s = 7 TeV in 2011 and 5.8 fb -1 at √s = 8 TeV in 2012. Individual searches in the channels H → ZZ(*) → 4l, H → γγ and H → WW(*) eνμν in the 8 TeV data are combined with previously published results of searches for H → ZZ (*) , WW (*) , bb and τ + τ - in the 7 TeV data and results from improved analyses of the H → ZZ(*) →4l and H → γγ channels in the 7 TeV data. Clear evidence for the production of a neutral boson with a measured mass of 126.0±0.4 (stat)±0.4 (sys) GeV is presented. This observation, which has a significance of 5.9 standard deviations, corresponding to a background fluctuation probability of 1.7×10 -9 , is compatible with the production and decay of the Standard Model Higgs boson.

Abstract:

The LHC luminosity upgrade, known as the High Luminosity LHC (HL-LHC), will require high-speed optical links to read out data from the detectors. The optical fibre connectors contained within such a link must have a small form factor and be capable of operating in the harsh radiation environment at the HL-LHC. MTP ribbon fibre connectors and LC single fibre connectors were exposed to 500 kGy(Si) of gamma radiation and their radiation hardness was investigated. Neither type of connector exhibited evidence for any significant radiation damage and both connectors could be qualified for use at HL-LHC detectors.