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SVD IR Mechanics
2Immanuel Gfall (HEPHY Vienna)18 November 2010
LayerSensors/Ladder
Origamis/Ladder
Ladders Length [mm] Radius [mm] Slant Angle [°]
3 2 0 7/8 262 38 0
4 3 1 10 390 80 11.9
5 4 2 14 515 115 17.2
6 5 3 17 645 140 21.1
Status One Month Ago
SVD IR Mechanics
Current Status• Parameters from the table stay the same• Added components that fix certain parameters• Interesting concept for end ring cooling• Updated isolation/support shell
3Immanuel Gfall (HEPHY Vienna)18 November 2010
SVD IR Mechanics
End Rings
• Split end rings
• Outer 3 layers offer openings for service routing
• Cooling is implemented into the ring structure
• Material: Stainless steel
• End rings are glued to the support cone
4Immanuel Gfall (HEPHY Vienna)18 November 2010
Cooling Inlet
Glueing Surface
Cooling Inlet
SVD IR Mechanics
Support Cone
• Carbon fiber reinforced plastic• Supports end rings• Creates service paths for PXD• Houses patch panels• Fixed to beam mask
5Immanuel Gfall (HEPHY Vienna)18 November 2010
Cooling Inlet
Patch Panel SpaceBackplane Dummy
SVD IR Mechanics
Beam Mask
• Provides background shielding• Supports SVD• Mounted to CDC
6Immanuel Gfall (HEPHY Vienna)18 November 2010
Forward Beam Mask
SVD IR Mechanics
Support Assembly
• Is built around beam pipe
• SVD support structure is split into halves
• Beam mask needs to be split
7Immanuel Gfall (HEPHY Vienna)18 November 2010
Beam Mask
End Rings
Support Cone
Patch Panel Space
SVD IR Mechanics
Most Urgent Issues
• Service paths
• SVD space requirement
• PXD space requirement
• Beam mask space allocation
• Slanted vs. Straight
8Immanuel Gfall (HEPHY Vienna)18 November 2010
SVD IR Mechanics
Current Concept
• PXD services outside of Mask
• Masks can be tightly fit around beam pipe
9Immanuel Gfall (HEPHY Vienna)18 November 2010
PXD Service Path Patch Panel Location
SVD IR Mechanics
Service Paths Forward Region
10Immanuel Gfall (HEPHY Vienna)18 November 2010
Ribbon Cables
• CAD study to show if service space is available• Almost straight cable paths are possible• Study shows that there is still space left• Shown scenario is the worst case
SVD IR Mechanics
Mask Thickness Study Backward• Search for areas < 10 mm• Minimal thickness ~7 mm• Additional 3 mm easily available
12Immanuel Gfall (HEPHY Vienna)18 November 2010
SVD IR Mechanics
Mask Thickness Study Forward
• Thinnest region ~ 5mm• Additional 2mm thickness is manageable• Mask thickness strongly depends on beam pipe shape!
13Immanuel Gfall (HEPHY Vienna)18 November 2010
SVD IR Mechanics
Barrel Support
14Immanuel Gfall (HEPHY Vienna)18 November 2010
• SVD 2 had a carbon fiber shell to combine forward and backward support
• Belle 2 SVD needs thermal insulation (Airex cover)• Carbon fiber – Airex sandwich• Adds stiffness that protects SVD during installation• Does not add more material as is present in SVD 2
Carbon Fiber Sandwich Carbon Fiber Layer
Airex Core
SVD IR Mechanics
Installation Support Proposal
• SVD will be very heavy• Suitable support for installation required• “Sled” from SVD 2 not sufficient• Oil drill style sliding tube for installation support
15Immanuel Gfall (HEPHY Vienna)18 November 2010
Oil Drill Style Tube
Slide Support
Flange
SVD
SVD IR Mechanics
Mechanical Feasibility of Slanted Design
16Immanuel Gfall (HEPHY Vienna)18 November 2010
Angle is determined by 2D cutout precision Manageable
Stiffness of rib around the angled section Sufficient
Slanted ribs are shorter and have to support less weight Ideal
End ring design and space allocation No concern
Beam mask thickness and space with slanted option Not ideal
Knee is reinforced by Crossply
Conclusion: Plausible but…
SVD IR Mechanics
… there are challenges
17Immanuel Gfall (HEPHY Vienna)18 November 2010
• Production of ribs is difficult because of small applicable forces for clamping
• Rib vibrates during routing• Water cutting could also lead to mechanical degradation• Better rib end ring link solution• Twist of sensor plane due to mechanical imperfection• There are even more!• Same problems for both options except for angle
precision!• Mask weight is an issue: between 15 kg and 25 kg!
SVD IR Mechanics
Conclusion
• Simulations do not give conclusive answers if slanted or straight option is better
• Mechanics are difficult for either solution
• Mechanics do not clearly favor any solution as either solution has its drawbacks
• Lets find solutions for the current situation and please stop spending more time on finding a decision! Available time is limited, we need to get going!!!!
18Immanuel Gfall (HEPHY Vienna)18 November 2010