ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 1 PST Design Update PST CDR october 2001

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 2 Current Design Status FEA Modeling –Design Variables –Recent Analysis Results –Low Stiffness Forwards –SCT Reaction Loads –Comparison to SCT analysis Testing –Friction Tester Constructed –Slider Materials Delivered –Carbon Samples Ordered Prototyping Plans –One Foot Sample Mandrel will be fabricated –Initial Autoclave Tryout Run Will Be Completed Soon –Mandrel Quotes Received

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 3 Design Variables Flange Material (PEEK or Carbon Fiber) Longitudinal Ribs Hoop Stiffeners (in Forwards) End Plug (PP1 panel) Flange Shape Barrel Constraints (ties across SCT diameter) Service Mass (incorporated in forward shell material) Fiberglass Forward Shells 1 or 2 Z Constraints Forward End Constraints

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 4 PST Model

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 5 FEA Model – Important Features Bolt flanges Sct mount pads End Plugs (1 mm equiv. carbon sheet) Hoop Hat Stiffeners (section view) End Support End Supports

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 6 Support Tube – Flange Details Flange x-section detail End view of barrel flange (forward flanges have no Mount bosses and no gas seal features – see below) barrel forward Constraint Areas

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 7 Flange Bolt Spacing Calculations Flange is conservatively modeled as a simple beam: - modeled as guided beam with length of bolt spacing/2 - cross section is assumed to be smallest flange section (forward) - flange force given by support tube loads (next slide) L L/2 Flange Load

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 8 Flange Bolt Spacing Calculations (cont.) Forward Tube Barrel tube Assumed rigid Forward And services mass Flange load=(Forward Load*( L / d )) Tube Deflection is calculated based on following assumptions: - forward tube pivots rigidly about bottom of flange - total forward tube mass (including services) is cantilevered - full flange load is taken by upper bolts only (3 bolts) - all structures rigid Frequency is estimated based on tube deflection using f =(1/2  * ( g /  ) 1/2 ) Flange delta tube Deflection (  ) desire frequency > 100 Hz number at left assumes no ribs -ribs act like bolt constraints -evenly spaced ribs allow half the number of bolts Design for 24 bolts in flange d L

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 9 Flange Face (machined layup) Flange base (Layup) Stiffeners (layups) Support Flange Bonded Assembly T-nuts (bonded) Old design - now gone for independent thermal barrier

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 10 PST Boundary Conditions

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 11 PST Position in Inner Detector PIXELSUPPORTTUBE SCT TRT ID Vee Rail ID Flat Rail Side CSide A View from top—all Tube Supports are Horizontal and Co-planar Properties TBD Constraint TBD Support Positions are shown, But constraint conditions are Not indicated here. +Z +X +Y Vertical Agreed Support Positions outside PST PST Support Conditions Under Investigation

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 12 Constraint Conditions: Fixed/Free ends Side CBarrelSide a Side CBarrelSide a Fixed X Fixed XYZ Fixed Z Fixed Y Fixed Forward Ends Free Forward Ends +Z +X +Y Vertical

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 13 Model Properties Material ModelMaterial Location Fiber Modulus (GPa) Bulk Modulus (GPa) Density (kg/m 3 ) High Mod. Carbon Shell, Hat Stiffeners Ultra High Mod. Carbon Flanges (Option 1) PEEK (graphite filled) Flanges (Option 2) N/A Glass (Quartz)Forward Shells HM Carbon (incl. service mass) Forward Shells Glass (incl. service mass) Forward Shells

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 14 PST Analyses

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 15 Original Model Side CBarrelSide a Side CBarrelSide a PEEK Flanges Longitudinal Ribs

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 16 Carbon Flange Material Side CBarrelSide a Side CBarrelSide a Carbon Flanges Longitudinal Ribs

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 17 Removing Ribs Side CBarrelSide a Side CBarrelSide a No Longitudinal Ribs

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 18 Constrain across SCT Side CBarrelSide a Side CBarrelSide a

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 19 Modal Shapes Hoops and End Plugs New Flange Shape Barrel Constraints Modes: 119 / 119 / 124 / 124

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 20 Low Stiffness Forwards Additional Hoops

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 21 Vibration Results Summary

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 22 Reaction Loads On SCT Model Material FX (N) FY (N) FZ (N) MX (Nm) MY (Nm) MZ (Nm) Carbon Glass Vertical Bending – Both Ends Both Ends Bent – 1 Z Constraint Model Material FX (N)FY (N)FZ (N)MX (Nm) MY (Nm) MZ (Nm) Carbon Glass Both Ends Bent – 2 Z Constraints Model Material FX (N)FY (N)FZ (N)MX (Nm) MY (Nm) MZ (Nm) Carbon Glass One End Bent – 1 Z Constraint Model Material FX (N)FY (N)FZ (N)MX (Nm) MY (Nm) MZ (Nm) Carbon Glass Horizontal Bending

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 23 Gravity Sag Calculations Carbon Glass

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 24 Comparison to SCT Analyses Discrepancies Due To: –Properties (SCT used different tube modulus; barrel modulus and forward modulus changed to glass) –Loads (pixel detector distributed, not supported on mounts) –Constraints Extra Z constraint SCT intrinsic compliance Simple instead of complete constraints at Barrel Projected uses ratio of SCT to our FEA with carbon forward tubes

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 25 Slider design - materials testing Friction Tester nearing completion –Applies variable pressure –Measures angular acceleration –Slides sample against interchangeable disk of given material M slider to be tested turntable (carbon disk) position is movable along arm M Mass provides normal force Encoder on shaft measures acceleration arm hinge G

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 26 Materials to Be Tested Sliding Materials –PEEK Glass Filled Virgin –Vespel Moly-Disulfide Filled Virgin –PPS Teflon, Carbon, glass, moly-disulfide filled Probably not viable Substrates –Carbon fiber disks (prospective material and Layup) 420 GPa Fiber 8 Ply Quasi-iso layup 437 micron thickness –Non-Woven glass mat on surface (some samples) Work just starting. No conclusions. May investigate roller depending upon results

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 27 Prototyping Plans Short Mandrel –1 foot long - 1 for glass, 1 for carbon – aluminum or steel –“Dry-run” in autoclave to determine thermal response –Determine final diameters from test layups Full Size Mandrel (forward length) –Quotes already received Approximately 14,000 to 20,000 USD 8 Weeks delivery –Plans to Fabricate forward prototype in glass All flanges and rail features Use for production forwards if diameters are correct Implications of Glass Forwards/Carbon Barrel on prototyping plans must be assessed

ATLAS Pixel Detector October 2001 Pixel Week N. Hartman LBNL 28 Plans For Near Future Import SCT Model into current analyses –Double check SCT loads – ascertain acceptability –Determine pixel stability with reduced stiffnesses Begin detailed design of flanges and tubes Fabricate sample tube sections (1 foot lengths) Analyze mounts/end constraints/service interactions –Eric Anderssen’s presentation