Research
Research
Experimental High-Energy Physics and Astrophysics
Fiber Calorimetry for Hadron Colliders -- L. Sulak, J. Sullivan
Forward calorimeters in SSC/LHC detectors are necessary to cover the pseudorapidity range from h = 2.5 to at least h = 5. They allow computation of missing transverse energy and far forward jet tagging. Operation at such high rapidity requires the use of a calorimetry technique that is radiation-resistant to gigards, fast, and insensitive to radioactivity, especially to neutrons. This can be accomplished by embedding quartz optical fibers in a copper absorber. In this calorimeter, the shower particles produce light by the Cerenkov effect, generating a signal of 6ns duration.
Unique to this new technology, and unlike
ionization detectors, the observed Cerenkov energy of hadronic
showers has a transverse dimension nearly an order of magnitude
smaller than that in conventional calorimeters that sample only
ionization energy. The size of the Cerenkov response to the
leading particles of the shower is the same size as the jet in
the forward direction, yet many times larger than it is in an
ionization detector. All of these characteristics allow a quartz
fiber calorimeter to be operated in the extreme working
conditions of a forward detector for the LHC collider at CERN.
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The primary physics goal of this project is to look for new physics (e.g., Higgs or Susy) at the higher energies available at the LHC. The Boston University group plans to conduct an in-depth study of the performance of different kinds of silica fibers in the presence of radiation load, a study of customized ultra-violet photodetectors and pixelized hybrid photodiodes, and the construction and beam testing of a full containment calorimeter module. This hadronic module will test all the features required for a forward calorimeter, including the transverse shower size, radiation resistance, speed, spatial resolution, transverse energy measurement, and implementation of a ET trigger. The end goal of this project will be a proof of feasibility and the collection of basic information necessary for the design of a forward calorimeter for the CMS detector at LHC. For more detailed information, see the group's web site at http://hep.bu.edu:80/~sullivan/ |
| The CMS Detector: Schematic diagram for the CMS detector being build at CERN for the LHC. |