lcws 31/5/2007erik johnson stfc,ral1 ilc vertex detector mechanical studies erik johnson on behalf...
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LCWS 31/5/2007 Erik Johnson STFC,RAL 1
ILC Vertex Detector Mechanical Studies
Erik JohnsonOn behalf of the LCFI collaboration
STFC, Rutherford Appleton Laboratory
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Outline
• Approaches to building a vertex detector
• Resource available• Future plans
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Approach for Building a Vertex Detector
• Close to interaction point
• Long lever arm• Low mass
– cooling
• Robust• Uniformity within a
layer
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LCFI Baseline Design• Individual long ladders• Arranged in a barrel
– Active length 250mm
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Barrel Layout
Beam pipe Ladder (detector element)
Foam cryostat
Beryllium support shell
Spring
Ladder block
Annulus block
Fixed end Sliding end
Readout and drive chips
Substrate
Silicon sensor
Beryllium support shell
Annulus and ladder blocks
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Barrel Layout
Layer no
No of Ladders
Radius(mm)
Active length(mm)
Active width(mm)
Tilt angle
Overlap(mm)
1 8 15(19) 100 13 0 0
2 8 26(28.5) 250 22 0 0.42
3 12 37 250 22 15 1.3
4 15 48 250 22 15 0.86
5 19 60 250 22 15 1.2
• Looking at:– the radius of the layers– width of elements– tilt angle
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Ladder Developments
• Foams – + low mass– take up space
• Prototypes of ladders– SiC (silicon carbide foam)– RVC (reticulated vitreous carbon foam)
• Some success with both• Problems with procuring thin silicon• Have new supplier of thin silicon –
Aptek Industries Inc
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SiC Foam Ladder• 20 um thick silicon• 1.5 mm thick SiC foam
– 8% relative density• Silicone adhesive pads
– 1mm diameter 200 microns high on ~5mm pitch
• ~0.14% X0SiC ladder
ladder block
glue
annulus block
mm
um
mm
um
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RVC Foam/Silicon Sandwich Ladder
• 20 micron thick silicon• 1.5 mm thick RVC foam
– 3% relative density• Silicone adhesive pads
– on ~5mm pitch• Tension ~1.5 N• ~0.08% X0
RVC sandwiched ladder
silicon spacer
ladder block
glue
annulus block
Tension
mm
um
mm
um
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Possible Alternatives
• Carbon fibre substrates
• Double sided detectors – reduce number of layers
• Use a Carbon fibre shell for one or more layers
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Resources Available
• Lab tools:– Cold survey cryostat with high precision laser
micrometer– Glue robot– Cooling test stand