Recent results from the DELPHI Barrel Ring Imaging Cherenkov counter

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Recent Results from the DELPHI Barrel Ring Imaging Cherenkov Counter

The DELPHI detector, installed at LEP, is equipped with RICH (Ring Imaging CHerenkov) counters. The Barrel part incorporates a liquid (C6F14) and a gaseous (C5F12) radiator providing particle identification up to 20GeV/c. The Cherenkov photons of both radiators are detected by TPC-like photon detectors. The drift gas (75% CH4 + 25% C2H6) is doped with TMAE, by which the UV Cherenkov photons are converted into single free photo-electrons. These are drifted towards MWPC’s at the end of the drift tubes and the space coordinates of the conversion point are determined. One half of the Barrel RICH is now equipped with drift tubes and has provided results from the liquid radiator since spring 1990. The gas radiator has been tested with C2F6 as a preliminary filling since August 1990. The data obtained demonstrate the good particle identification potential. For the liquid radiator the number of detected photons per ring in hadron jets is N=8, whereas for muon pairs (single tracks) N=10 has been obtained. For the gas radiator 2.1 photons per track were observed, which demonstrates the good functioning of the focussing mirrors, as for C2F6 this is close to the expected value. © 1991 IEE

Engineering for the ATLAS SemiConductor Tracker (SCT) End-cap.

The ATLAS SemiConductor Tracker (SCT) is a silicon-strip tracking detector which forms part of the ATLAS inner detector. The SCT is designed to track charged particles produced in proton-proton collisions at the Large Hadron Collider (LHC) at CERN at an energy of 14 TeV. The tracker is made up of a central barrel and two identical end-caps. The barrel contains 2112 silicon modules, while each end-cap contains 988 modules. The overall tracking performance depends not only on the intrinsic measurement precision of the modules but also on the characteristics of the whole assembly, in particular, the stability and the total material budget. This paper describes the engineering design and construction of the SCT end-caps, which are required to support mechanically the silicon modules, supply services to them and provide a suitable environment within the inner detector. Critical engineering choices are highlighted and innovative solutions are presented – these will be of interest to other builders of large-scale tracking detectors. The SCT end-caps will be fully connected at the start of 2008. Further commissioning will continue, to be ready for proton-proton collision data in 2008