18 November 2010

Immanuel Gfall (HEPHY Vienna)

SVD IR Mechanics

7th B2GM

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

Space Requirement SVD

11Immanuel Gfall (HEPHY Vienna)18 November 2010

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