1. ATLAS Pixel Detector Pixel Support Tube Interfaces Pixel Support Tube PRR CERN, Geneve E. Anderssen, LBNL

2. ATLAS Pixel Detector February 2003 PRR PST E. Anderssen LBNL overview Interface definition Load cases tolerances

3. ATLAS Pixel Detector February 2003 PRR PST E. Anderssen LBNL Pixel Support Tube Barrel

4. ATLAS Pixel Detector February 2003 PRR PST E. Anderssen LBNL ID Layout Pixel System and Beampipe Installed (beampipe position locked in place) SCT TRT Side C Side A Services and Beampipe Support Frame Services and Beampipe Support Frame Pixel Detector 2 Additional Supports Added After Adjustment: Wire supports (R) TBD Beam support (R,Z) TBD PST Shown in Orange

5. ATLAS Pixel Detector February 2003 PRR PST E. Anderssen LBNL Support Condition of Pixel Support Tube SCT TRT Support condition of Pixel Support Tube intends to couple in stiffness across diameter Fixed XYZ Fixed YZ (N/A) Fixed XY Fixed Y ID Vee Rail (float Z/dogged Z) (constrained XY) ID Flat Rail (float XZ) (constrained Y) +Z -X Side CSide A +Y Vertical SCT Vee Rail (float Z/dogged Z) (constrained XY) SCT Flat Rail (float XZ) (constrained Y) View from top—all Tube Supports are Horizontal and Co-planar Properties TBD Constraint TBD

6. ATLAS Pixel Detector February 2003 PRR PST E. Anderssen LBNL ID Layout Drawing

7. ATLAS Pixel Detector February 2003 PRR PST E. Anderssen LBNL LOADS Load ScenarioR AllowanceR-phi AllowanceZ Allowance Structural Integrity100 microns 200 microns

8. ATLAS Pixel Detector February 2003 PRR PST E. Anderssen LBNL interfaces Environmental –Heaters—discussed in Heater performance Doc –Gas Seal—seal at flanges Geometric –To be covered in the following slides: –SCT –PP1 –Package

9. ATLAS Pixel Detector February 2003 PRR PST 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

10. ATLAS Pixel Detector February 2003 PRR PST E. Anderssen LBNL Interface to SCT Models laid out to meet required interface geometry Still missing part between SCT/PST Barrel lengthened to allow for seal and machining of hole in mount pad

11. ATLAS Pixel Detector February 2003 PRR PST 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

12. ATLAS Pixel Detector February 2003 PRR PST 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

13. ATLAS Pixel Detector February 2003 PRR PST E. Anderssen LBNL Mount tolerances to SCT PST to SCT mount achieved with transfer jig—shown in Assembly talk Tolerance of position of PST wrt SCT is dominated by meeting envelope in forward (R242) Position of Pixel mounts are placed later, relative to SCT mounts to achieve good Pixel-SCT relation

14. ATLAS Pixel Detector February 2003 PRR PST E. Anderssen LBNL Build tolerances of PST 2276 50   480 dia  = (2276/480)*0.050 = 0.240mm Barrel and forward flange perpendicularity has the same contribution to error

15. ATLAS Pixel Detector February 2003 PRR PST E. Anderssen LBNL Build tolerances of PST 2276 100   480 dia  = (3907/1631)*0.100 = 0.240mm Barrel flange position (0.100) coincidentally has the same contribution to the error as well 1631

16. ATLAS Pixel Detector February 2003 PRR PST E. Anderssen LBNL Build tolerances of PST 2276 100   480 dia  = offset = 0.100mm forward flange position (0.100) directly contributes to error 1631

17. ATLAS Pixel Detector February 2003 PRR PST E. Anderssen LBNL Build tolerances of PST Barrel perp:240   Gravity sag is not error—it is a constant offset of (0.500) in one direction only 1631 Barrel position: 240  Forward perp: 240  Forward position: 100  Gravity sag: 500  1.180mm 239.5 242 240.82 Error is 0.82mm sum or 0.43mm in quadrature Gravity sag is always 0.5mm

18. ATLAS Pixel Detector February 2003 PRR PST E. Anderssen LBNL Build tolerances of PST  Gravity sag is not error—it is a constant offset of (0.500) in one direction only 1631  3092 815  =  *(815/3092) = 1.18 * (815/3092) = 0.311mm The position tolerance on the sct mounts relative to the flanges can therefore be budgeted as 311  Mount Tolerance 250  Flexure Machining 50 

19. ATLAS Pixel Detector February 2003 PRR PST 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

20. ATLAS Pixel Detector February 2003 PRR PST 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 Pixel Detector SCT Interface Block Pixel Mount Flexure Missing Integrated Model with both PST and Pixel Detector Frame

21. ATLAS Pixel Detector February 2003 PRR PST E. Anderssen LBNL PST Mount Scheme Goals Rely on Bolted and Pinned Interfaces for stability Benefit from the stiffness of the SCT across the Diameter, but minimize extraneous loads: Minimize Internal load on SCT/Pixel –CTE mis-match of very stiff objects leads to potentially high forces –Use of Flexures to minimize induced tension in the SCT –Decouple moments for horizontal deflection of PST forward end Minimize External Load on ID Barrel –Mis-match of Cryostat and Support tube yields potentially high strains –Use of larger flexures at Forward End Support to minimize load

22. ATLAS Pixel Detector February 2003 PRR PST 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

23. ATLAS Pixel Detector February 2003 PRR PST 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

24. ATLAS Pixel Detector February 2003 PRR PST 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

25. ATLAS Pixel Detector February 2003 PRR PST E. Anderssen LBNL Pixel Mount Block and preload spring

26. ATLAS Pixel Detector February 2003 PRR PST E. Anderssen LBNL Rail Interface This is the interface of the Pixel Package to the PST –Includes both Pixel Detector and Beam Pipe Support Structure The Pixel detector uses this interface until it is at the Pixel mount location Actual slider geometry has been preliminarily accepted Slider Materials have been investigated Rail Materials are undergoing friction testing How the slider is held to the frame or to the package components has not been designed

27. ATLAS Pixel Detector Rails

28. ATLAS Pixel Detector February 2003 PRR PST 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