LCD-ALCPG

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LCD-ALCPG

• Presentation at the ALCPG-SLAC
• Meeting
• Progress Report of Work at Colorado
• January, 2004

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LCD-ALCPG

• THE GROUP
• Shirley Choi, Bradford Dobos, Tyler Dorland,
  Eric Erdos,
• Jeremiah Goodson, Jack Gill, Jason Gray
• Andrew Hahn, Eric Kuhn, Alfonso Martinez
• Kyle Miller, Uriel Nauenberg, Joseph
  Proulx,
• Jesse
  Smock

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LCD-ALCPG

• ACTIVITIES
• Develop a new geometrical structure in
  calorimetry that is cost effective and will have
  the energy and time resolution required in a
  Linear Collider environment.

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LCD-ALCPG

• The Calorimeter
  
• Scintillator tile layers 5 x 5 cm2, 2mm thick.
• Alternate layers are offset. See next slide.
• Effective 2.5 x 2.5 cm2 spatial resolution.
• Reduces by 25 the number of channels when
  compared to 1 cm2 tile structures.

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LCD-ALCPG

• The Basic Geometrical Structure

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• The Tile Arrangement

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• The Calorimeter test unit we have built
• Cosmic
  Ray Trigger

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• New Readout Equipment
• We have LabView Installed.
• University money.
• We have purchased readout from National
  Instruments.
• We are calibrating the ADCs. Learning the power
  of LabView.
• We already know we have problems with
  calorimeter low pulse height from cosmic muons.
  It is time to have fun investigating.
• A lot of work in the near future.
• 
  
  

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• Test Calorimeter in Box Test Pulse
  Digitized LabView

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• Labview Pulse Height Analyzer for a
  Pulser

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LCD-ALCPG
Issues on Spatial Resolution

• Moliere Radius
• Comparison of Photons Spatial Resolution with
  no offset case
• Resultant Spatial Resolution Comparison
• Net Mass and Jet Directional Resolution
• Can we Separate Hadrons from the Shower
• Energy Flow Resolution of 2.5 x 2.5 cm2 versus 1
  cm2 tile structures.

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LCD-ALCPG

• Standard Dev. of the Shower Energy
  Distribution
• 5 Gev Photon 75
  GeV Photon Shower ? of Dist. vs P

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• Moliere Radius
• The Moliere Radius is defines as containing 90
  of the
• Energy. This is roughly equivalent to 1.63 x ?
  1.63 x 1.5
• Moliere Radius 2.5
  cm.

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• Spatial Resolution
  
  1 dimension(z)
  d(?)?(?)

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LCD-ALCPG

• Mass of the
  Z0? e e
• No Offset
  Offset

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• Directional Biases in the Shower Fit
• red 00 dip angle
  blue 450 dip angle

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• After 1st order Corrections

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Understanding the Fit Bias

fitted direction
g direction
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• Z0 Mass Fit after Bias
  Correction

no offset
offset
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• Photon Energy Spectra from Reactions
  at 1 TeV

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• Low Energy End of the Photon Energy Spectrum
  from Reactions
• 
  at 1 TeV

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• 100 GeV Shower Deposition
  Resolution
• No Conditions
  2 of shower in few layers

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• More on Resolution
• Some evidence that resolution deteriorates as dip
  angle
• increases. Being investigated.

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• Distance Between Particles at Calorimeter

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• What have we learned so far
• Loosing light from curved (2.5 cm. radius)
  fibers. Our colleagues from Italy have indicated
  fibers need to be annealed. We have an oven. Will
  study this problem next.
• We can gang 3 or 5 layers together without much
  loss in resolution. We need to study this more
  carefully for 1-2 GeV photons.

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• Issues in Resolution
• Dynamic Range 0.5-250 GeV. Can we achieve
• good energy resolution over this spectrum
  in the electromagnetic calorimeter device. Number
  of readout bits needed.
• Can we achieve good spatial directional
  resolution in the low energy end of the spectrum.

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LCD-ALCPG
What Needs to be Studied

• We need to study the resolution effectiveness
  via simulation. Need to understand our present
  resolution.
• We need to study the light collection efficiency,
  uniformity. This will be done with cosmic rays.
  Tyvek versus Radiant Mirror paper.
• We need to study how to construct these in a
  simple manner to maintain cost effectiveness
  while maintaining accuracy.

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LCD-ALCPG

• Continue, What Needs to be Studied
• We need to develop Extruded Scintillator
  techniques with the Fermilab folks to determine
  whether we can maintain thickness dimensions to
  within a fraction of a mm.
• Can we inscribe grooves 5 cm apart in Extruded
  Scintillator and can we maintain lateral
  dimensions to a mm.
• We need to develop Pattern Recognition and
  Energy Flow algorithms that use our different
  geometrical arrangement. We are now starting this
  effort.

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LCD-ALCPG

• Continue, What Needs to be Studied
• We need to compare our algorithms with those of
  the silicon based study to determine cost benefit
  alternatives.
• Study electronics readout APDs, HPDs,VLPCs. We
  have started a collaboration with Fermilabs
  electronics group.
• This requires cryogenic techniques we do not
  have. Are investigating collaborative
  arrangements with Fermilab to provide cryogenics
  help.

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• A LOT OF WORK IN NEAR FUTURE

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