LumiCal High density compact calorimeter at the ILC

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LumiCalHigh density compact calorimeter at the
ILC

• Wojciech Wierba
• Institute of Nuclear Physics PAS
• Cracow, Poland

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• Bhabha process ee- gt ee- (?)
• Accuracy of the luminosity measurement 10-4
• Covers polar angles ? between 26 and 82 mrad.

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The New Layout of the Forward Region

• Final focus system L 4.15 m
• Compact design of the LumiCal
• More space for electronics and cabling

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Mechanical design

• Segmented silicon sensors interspersed into the
  tungsten half disks
• Two half barrels to allow for mounting on closed
  beam pipe
• The blue bolts support the heavy part of the
  detector, tungsten half disks
• The red bolts carry only the sensors
• Holes for precision survey the sensors position

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Silicon sensorsPads design

• Shower peak design
• First 4 rings will consist of 24 radial sectors
  and 10 cylinders
• Next 15 rings will consist of 24 radial sectors
  and 22 cylinders
• Last 11 rings will be segmented as the first 4
  rings

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The layout of a silicon sensor of the pad version
The fine segmentation
The rough segmentation
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Silicon sensorsStrips design

• The odd rings contains 64 concentric strips
• The even layers have 120 radial strips

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The layout of a silicon sensor of the strip
version
The odd half layer
The even half layer
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Pads or strips ?
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Precision assembly and positioning of the LumiCals

• To achiev ?L/L 10-4
• Inner radius of LumiCal 0.7 µm
• Distance between LumiCals 60 µm
• Transversal (x, y) position 100 µm

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Precision assembly of the LumiCal

• Optical survey of the sensors marks through the
  holes
• On line check of the sensors position (?)
• Inner radius of detector after closing the half
  barrels
• Position of the sensors after kipping the LumiCal
  to working position
• Thermal stability (constant temperature?)

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Monitoring of the LumiCal position

• The beam pipe is proposed as the reference.
• Precision survey of the beam pipe before
  instaling
• The Beam Position Monitors are mounted inside the
  vacuum pipe gt allow to determine LumiCal
  position with respect to the beam

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Simple laser CCD camera position measurements
Resolution 1mm if the accuracy of determination
of the centre of the light spot is better than
0.1pixel
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X, Y, Z displacement measurement

• BW camera
• 7.5 µm x 7.5 µm pixel size
• New precision movable table
• Semiconductor lasers

Will be tested soon
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Conclusions
More realistic MC

• Rotation of the odd and even planes by 7.5
• Gaps between tiles
• Pads edges, guard rings
• Concentric stripes divided in 6 parts, radial in
  2 parts for half plane
• Readout electronics noise