FORWARD%20ATLAS

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FORWARD ATLAS

Andrew Brandt

• Luminosity measurement for ATLAS
• (based on update at Freiberg in October)
• Forward Physics with ATLAS

major contributions from Per Grafstrom (CERN),
Michael Rijssenbeek (Stonybrook), Brian Cox
(Manchester
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LOI submitted in March 2004, approved by ATLAS
management in summer
1) Roman pots for Luminosity measurement 2)
LUCID-cerenkov detector for Lum monitoring
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Absolute Luminosity from Coulomb Scattering

• Elastic scattering at micro-radian angles
• L directly determined in a fit (along with sTOT,
  r, and b)
• effectively a normalization of the luminosity
  from the exactly calculable Coulomb amplitude
• Required reach in t
• Requires
• small intrinsic beam angular spread at IP
• insensitive to transverse vertex smearing
• large effective lever arm Leff
• detectors close to the beam, at large distance
  from IP (240 m)

Paralleltopoint focusing
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ECR for Installation
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Roman Pot Detectors

• Square scintillating fibers
• Kuraray 0.5 mm 0.5 mm fibers
• 10 layers per coordinate
• 50 µm offset between layers

scintillator plate for triggering
y-measurement detector
x-measurement detector
proposed UTA responsibility in LOIcould include
trigger electronics as well
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List of tasks and deliverables leading to the
construction of a prototype fiber detector

• design optimization (fiber layout, staggering,
  fiber routing)
• selection and characterization of components
• scintillating fibers optical, geometrical and
  mechanical parameters (single vs. double
  cladding)
• development and demonstration of production
  techniques
• fiber cutting, polishing, bending, gluing
• interfacing fibers to photo detectors
• bundling of fibers and couple to the photo
  detector
• defining a concept for a vacuum tight fiber
  window
• construction and characterization of at least 2
  fiber layers
• analysis of geometrical precision
• determination of cross-talk
• determination of light yield for MIPs

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Points with no or little progress

• Design and construction of the pot
• Need institute with interest in mechanical
  engineering
• Development of a detector integration concept
• Establishing a collaboration for the
  scintillating fiber detector
• Precision movements of the pots
• Motors
• Control
• Selection and characterization of the photo
  detector

Lots of room for UTA to make an impact given
resources
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Conclusion

• A lot of progress since overview week in Prague
• LOI
• Optics
• ECR to the machine
• Start of developing work for a prototype detector
• Collaboration is starting on front-end
  electronics
• Not enough progress to form a collaboration to
  be able to see a clear timeline for a working
  system