Silicon sensors for LumiCal Two possible options

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Silicon sensors for LumiCalTwo possible options

• Wojciech Wierba
• Institute of Nuclear Physics PAN
• Cracow

2
Pads

• 12 sectors in ? (15)
• 15 cylinders in r (width 13.33 mm)
• 180 pads on half plane

• Inner pad - 302 mm2
• Outer pad - 955 mm2
• Capacitance ratio 3.16

Odd and even planes rotated by 7.5 deg
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Strips

• 64 concentric strips (width 3.125 mm)
• 60 radial strips (3)
• Inner concentric strip - 800 mm2
• Outer concentric strip - 2734 mm2
• Capacitance ratio 3.42
• Radial strips - 1885 mm2

4
Wafer size

• Small wafers are not suitable, causes a lot of
  tiles per half plane
• Best wafer size 24 inch not available
• 12 inch wafer acceptable (300 mm dia)

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Tiles of the sensors for both options (12 wafer)
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Gap between tungsten plates

• Half plane of the detector will consist 3 tiles

• Support to glue tiles and place for the
  electronics
• Ceramic plate 0.5 mm thick
• Silicon sensor 0.3 mm thick

The gap between tungsten plates should be in
order of 1 mm
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Comparison of the two options
Pads Strips
Masks 1 2
Number of channels 10800 7560
Energy resolution ? 40 ?E ? 31 43 ?E
Angular resolution ???? 70 - 90 ?rad ???? 50 90 ?rad
Capacitance ratio on tile 3.16 3.42
Mean area of pad/strip 630 mm2 898 mm2
Smalest pad/strip 302 mm2 267 mm2
Largest pad/strip 955 mm2 1885 mm2
Capacitance ratio 3.16 7.06
Bias, coupling to amplifiers complicated easier
Number of sensors per tile 60 20 radial, 64 conc.
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More realistic MC

• Rotation of the odd and even planes
• Angle pads 7.5, strips - 7.5 ?
• Gaps between tiles (0.1 0.2 mm to be
  discussed)
• Pads edges, guard rings
• Concentric stripes divided in 3 parts for half
  plane
• Gap between tungsten plates 0.8 1.0 mm

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Conclusions

• Both options are comparable
• Number of channels is near the same
• Resolutions (energy angular) are near the same
• Strips needs 2 masks
• Strips needs probably 2 types of amplifiers
• Pads have more complicated bias and coupling
  connections