1. ATLAS Pixel Detector Pixel Support Tube Interfaces LBNL Internal PST Review E. Anderssen, LBNL

2. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Overview Structures and Position in ATLAS Internal Interfaces –Rail Geometry/Sliders/Roller –Pixel to PST Mounts –PP1/PP0 Mount/External Interfaces –PIXEL to SCT Mount Block –Forward End Support Flexures

3. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL PST Key Structures Hoop Hat Stiffeners (section view) 30 45 10 SCT Flexures and mount pads Forward End Flexures Forward A Forward C Barrel PST Flanges PP1 End Plug

4. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Pixel Package—Internal Interfaces Service and Beampipe Support Pixel Detector PP0 PP1 Beam pipe Support Rail Sliders Beam pipe Support Rail Sliders Pixel Frame Rollers Pixel Mounts

5. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Package interfaces to PST Package has Several Physical Interfaces to PST –Rail Sliders/Rollers on Frame and Service/Beampipe Support –Pixel Mount Blocks –PP1 End Plate Installation Configuration –Frame Rollers engaged, Pixel Mounts not Yet Engaged –Rails Supports Entire Detector –PP1 Fixed Portion Clears Internal Dimensions of PST Installed Configuration –Frame Rollers Disengaged, Pixel Mounts engaged –Rails Continue to support Services and Beampipe –PP1(s) are Supported By PST end Flanges

6. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Inner Detector Layout

7. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL

8. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Patch Panel Zero PPO region preliminary layout—cable routing and assembly sequence not completed Nominal routing for tubes shown here—allows access to rails and pixel supports (discussed later) Pixel Mount Block Access Frame Rollers Service Sliders

9. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Patch Panel One PP1 layout determines final length of the Forward section of the PST—Layout of region is preliminary, and will require physical modeling to complete

10. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Mount Interfaces and Geometry Pixel detector is supported on mounts integrated into Flange of the Barrel PST Barrel PST is mounted to the Barrel SCT via Flexures and fixed Support –Mount Pad integrated with Flange of Barrel PST directly couples SCT and Pixels decoupling as much as possible the shell of the PST Forward PST sections are mounted to the Barrel PST via a flange, and supported at their ends from the PST Support structure (formerly Beampipe support) Rails discussed later, however for completeness: –Pixel Detector rides in with package on rails and transitions to mounts in the Barrel section of the PST –Remainder of Package (Service/Beampipe support Structure) remains on rails

11. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Mount Schematic Pixel Support Tube Mounts to SCT Interface Block Via a Flexure Pixel Detector Mounts to PST Barrel Via the Pixel Mount SCT Not shown here Pixel Detector SCT Interface Block Pixel Mount Flexure Missing Integrated Model with both PST and Pixel Detector Frame

12. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Interface to SCT Interlink (Barrel PST support) Pixel Support Tube is supported by Three Flexures and One “Fixed Support” –All Flexures and the Fixed Support have identical bolted and pinned interfaces with PST Barrel and SCT Interface Block Interface Blocks which penetrate the SCT Thermal Enclosure are mounted to the SCT Interlink All Interface Blocks are identical –Brief modification of the end of the interlink to accommodate –Penetration through SCT Barrel Thermal enclosure standardized

13. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Proposal for SCT - Pixel Interface - 4 Blocks fastened to the SCT horizontal interlinks - Adjustement, if needed, by shimming or machining PST blocks Dimension Is OK Slide of E. Perrin Need to Make integrated Model/Interface Drawing with relevant parts of SCT

14. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL SCT Inner thermal enclosure - I propose to fix the TE inner cylinder directly to Barrel 3 - To save space. - To try to simplify penetrations and sealing. Flexure PST BARREL MOUNT PAD 3mm Shim (0-6mm As REQ) R240 R253.5 Z 780

15. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Manufacturing and Assembly implications Flexures Mount Directly to SCT Interface Block (prior to PST Insertion) Mounting Pixel Support Tube requires access to inside of Barrel PST –Pins and bolts into Flexure are accessed through cutout –“Adjustment” is by shimming (horizontal) and flexure replacement (vertical) –Adjustment only required in emergency in pit—nominally PST is centered in SCT Above implies that set of pre-machined flexures will be required Pinned interfaces require accurate mating and alignment of interfaces Proposed solution is to Bond PST mount Pads in place –Depending on Schedule either Transfer Tooling or Bond in place

16. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Manufacturing Accuracy by Bonding Whether SCT or Mistress tool is used depends on Schedule Bond Gap can currently account for +/- 200 , but can easily accommodate up to 1mm if required (need to change some nominal dimensions) Bond Between Mount Block and PST Mount Pad can be made last Mistress tool or SCT AS Built

17. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Interface Geometry 780 803 PST Mount Flexure 253.5 SCT Barrel 3 And Interlink

18. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Mount Block Analysis Flexures chosen for tight packaging Accurate manufacture and predictability of analysis Large Factors of Safety against yield at maximum foreseen loads Have assumed that loads from Integrated SCT/PST model represent worst case loads (2mm end deflections of PST)

19. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL How Much Float is needed Fixed Point to End of SCT yields an internal stress – Due to CTE mismatch on the order of 1-2ppm/C Fixed point to end of Cryostat yields an External load on the ID Barrel via the SCT – There is potentially a large CTE mismatch between Cryostat and the Pixel Support Tube – Case where Cryostat raised 10C above no-power condition, and where Support tube CTE is unusually high (>1ppm/C) Flexures need to assure minimal loads at these extensions yet remain stiff in the orthogonal directions fixed 1.6m  120  4.25m @ +1ppm/C2.65m @ +1ppm/C 4.25m @ +23ppm/C  1.2mm 2.65m @ +23ppm/C  700  -20C +30C

20. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Barrel Flexure Analysis 0.5  /N 0.17  /N 2.3  /N 50N 147N 150N 75  25  115 

21. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Needed Load Set on Flexure FxFx FzFz FyFy MyMy MzMz MxMx DirectionLoad Required Limit Load Fx121N 450N (~250  ) Fy211N2.3kN Fz68N 400  (150N)* Mx322N.m750Nm My189N.M24.6Nm Mz53N.m19.6Nm flex *Load at 400  deflection—stop prevents further travel preventing plastic deformation of flexure. Load then transfers to bolted joint which has a limit load Equal to F y.  No limit in Fy foreseen due to high factor of Safety  Limits in X,Z make FoS similar to Fy (bolted interface)

22. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Design of flexure against Failure Flexure Yields in Z- Travel at ~400  deflection – Stops included to limit travel to 400  or less Fy Ultimate for Flexure depends on Tensile stress area of Webs on Flexures – Area of webs ~20mm 2 – area of Bolt M6 ~20mm 2 Fx will have limits built into interface pads as shown in figure above on right Built Prototype Flexure without Stops to verify plastic limits Will test Stiffness of Flexure with TVH system F y =5.2kLbf M6 Fastener FXFX FxFx FzFz FyFy MyMy MzMz MxMx Flexure PST Mount PAD Limit to <150  Shim

23. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Forward Flexure Plastic Limit stop will be incorporated in design, and integrated with Flex lock mechanism necessary for lock-out during Installation of Pixel Detector 80

24. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Pixel Support Condition on PST This is an attempt at a pseudo-kinematic mount condition Three points are fixed, with one adjustable in height— nominally this is one of the ‘flat’ mounts Mounts will be adjusted in co-planarity to match mount surfaces—reducing twist of frame

25. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Pixel Frame Mounts Prototype of Pixel mounts developed Axle and Bearing design refined –Angular contact bearings –Ceramic race –Ceramic Balls –Titanium Shaft Contact analysis shows one ball can take full detector load (no brinnelling) Statistical tolerance analysis shows 5 or more balls in contact Shaft is Full Hard 6Al4V Ti alloy with Nitrided Surface

26. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Interface to Pixel Frame Endplate Three mounts fixed, One adjustable vertically Two dowel pins, Three mounting screws Holes machined in Ears of Endplate Endplate registered to End frame by tight shoulder screws in same ear

27. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Pixel Mount Block and preload spring

28. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Preload Flexure Flexure Designed for 105N Preload –Nominally equals detector mass plus some margin Deflection at preload nominally 1mm –Large compliance allows for moderate machining and misalignment tolerances Factor of Safety against yield at Max flex design travel 1.7

29. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Flexure PST BARREL MOUNT PAD R240 SCT Interface surface pixel 40  Budget Mount Deflection Budget Gravity Deflection Budget of 40  is assumed  80Hz assumed for vibrational stability Flexure/Mount Pad-Flange/Pixel mount all contribute Assumed 20  for Pixel mount, 20  for rest

30. ATLAS Pixel Detector September 2002 Internal Review E. Anderssen LBNL Deflection of Mounts Tip deflection of Long Shaft is 20 . Angle change of shaft from pillow block adds 8 . Nominal budget for Pixel mount was 20 . –Long shaft is coupled with short PST interface block –Short shaft has less shaft deflection but more PST Pad windup Total Budget of 40  between SCT and Pixels is shared between these mounts and the PST mount pad Total budget is close to met—see Neal’s talk