1. LCWS 31/5/2007Erik Johnson STFC,RAL1 ILC Vertex Detector Mechanical Studies Erik Johnson On behalf of the LCFI collaboration STFC, Rutherford Appleton Laboratory

2. LCWS 31/5/2007Erik Johnson STFC,RAL2 Outline Approaches to building a vertex detector Resource available Future plans

3. LCWS 31/5/2007Erik Johnson STFC,RAL3 Approach for Building a Vertex Detector Close to interaction point Long lever arm Low mass –cooling Robust Uniformity within a layer

4. LCWS 31/5/2007Erik Johnson STFC,RAL4 LCFI Baseline Design Individual long ladders Arranged in a barrel –Active length 250mm

5. LCWS 31/5/2007Erik Johnson STFC,RAL5 Barrel Layout Beam pipeLadder (detector element) Foam cryostat Beryllium support shell Spring Ladder block Annulus block Fixed endSliding end Readout and drive chips Substrate Silicon sensor Beryllium support shell Annulus and ladder blocks

6. LCWS 31/5/2007Erik Johnson STFC,RAL6 Barrel Layout Layer no No of Ladders Radius (mm) Active length (mm) Active width (mm) Tilt angle Overlap (mm) 1815(19)1001300 2826(28.5)2502200.42 3123725022151.3 4154825022150.86 5196025022151.2 Looking at: –the radius of the layers –width of elements –tilt angle

7. LCWS 31/5/2007Erik Johnson STFC,RAL7 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

8. LCWS 31/5/2007Erik Johnson STFC,RAL8 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% X 0 SiC ladder ladder block glue annulus block mm um mm um

9. LCWS 31/5/2007Erik Johnson STFC,RAL9 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% X 0 RVC sandwiched ladder silicon spacer ladder block glue annulus block Tension mm um mm um

10. LCWS 31/5/2007Erik Johnson STFC,RAL10 Possible Alternatives Carbon fibre substrates Double sided detectors – reduce number of layers Use a Carbon fibre shell for one or more layers

11. LCWS 31/5/2007Erik Johnson STFC,RAL11 Resources Available Lab tools: –Cold survey cryostat with high precision laser micrometer –Glue robot –Cooling test stand

12. LCWS 31/5/2007Erik Johnson STFC,RAL12 Future Plans Continue prototyping foam ladders Build and test carbon fibre shell Computer simulations –FEA and CFD