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SVT Mechanics

SVT Mechanics. Baseline SuperB SVT configuration Collected pictures from the BaBar SVT Open issues & Strategy. SVT Mechanics, March 2011. Giuliana Rizzo – Filippo Bosi Universita’ & INFN Pisa. 20 cm. old beam pipe. new beam pipe. 30 cm. 40 cm. Layer0.

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SVT Mechanics

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  1. SVT Mechanics • Baseline SuperB SVT configuration • Collected pictures from the BaBar SVT • Open issues & Strategy SVT Mechanics, March 2011 Giuliana Rizzo – Filippo Bosi Universita’ & INFN Pisa SVT Mechanics Meeting – March, 9 2011

  2. 20 cm old beam pipe new beam pipe 30 cm 40 cm Layer0 The SuperB Silicon Vertex Tracker BaBar SVT • 5 Layers of double-sided Si strip sensor • Low-mass design. (Pt < 2.7 GeV) • Stand-alone tracking for slow particles. • 97% reconstruction efficiency • Resolution ~15μm at normal incidence SVT • SuperB SVT based on Babar SVT design for R>3cm. BUT: • Reduced beam energy asymmetry (7x4 GeV vs. 9x3.1 GeV) requires improved vertex resolution (~ factor 2 needed) • Layer0 very close to the IP (R~ 1.5 cm) with low material budget • Layer0 area 100 cm2 • Background levels depends steeply on radius  Layer0 needs to have fine granularity and radiation tolerance Bp pdecay mode, bg=0.28, beam pipe X/X0=0.42%, hit resolution =10 mm Dt resolution (ps) • Layer0 subject to large background and needs to be extremely thin: Track rate > 5MHz/cm2, > 3MRad/yr, < 1 %X0 SVT Mechanics Meeting – March, 9 2011

  3. Complexity Digital tier Analog tier Sensor Wafer bonding & electrical interconn. SuperB SVT Layer 0 technology options • Striplets option:mature technology, not so robust against background occupancy. • Marginal with back. track rate higher than ~ 5 MHz/cm2 • FE chip development & engineering of mod. design needed • Hybrid Pixel option:viable, although marginal. • Reduction of total material needed! • Reduction in the front-end pitch to 50x50 μm2, fast readout (developed for DNW MAPS)  FE prototype chip (4k pixel, ST 130 nm) successfully tested with pixel sensor matrix connected. • CMOS MAPS option:new & challenging technology. • Sensor & readout in 50 μm thick chip! • Extensive R&D (SLIM5-Collaboration) on • Deep N-well devices 50x50μm2 with in-pixel sparsification. • Fast readout architecture with target hit rate O(100MHz/cm2) • CMOS MAPS (4k pixels) successfully tested with beams. • Thin pixels with Vertical Integration: reduction of material and improved performance. • Two options are being pursued (VIPIX-Collaboration) • DNW MAPS with 2 tiers • Hybrid Pixel: FE chip with 2 tiers + high resistivity sensor SVT Mechanics Meeting – March, 9 2011

  4. Layer0 Strategy Plan • Start data taking (~ 2016) with striplets (baseline option for TDR): • Better physics performance (lower material ~0.5% vs 1% hybrid pixel, MAPS or thin hybrid pixel in between but not yet mature!) • Upgrade Layer0 to pixel (Hybrid or CMOS MAPS), more robust against background, for the full Luminosity (1-2 yrs after t0). • SVT Mechanics will be designed to allow a quick access/removal of Layer0 ~10% better ~20% more Luminosity SVT Mechanics Meeting – March, 9 2011

  5. SVT baseline configuration for TDR SuperB Interaction Region Schematic SVT superimposed Layer 0: Striplets modules • CDR design is being revised for TDR • Quite complex mechanical structure need to fit inside the L1 radius 3.3 cm External Layers: • Similar to the present BaBar SVT: double sided silicon detectors 300 um thick • Assume same BaBar radii for the 5 layers (3-15 cm) • L1-L2-L3 barrel shape • L4-L5 arch shape • Extend coverage down to 300 mrad FW and BW • In BaBar it was 300 mrad FW and 520 mrad BW SVT Mechanics Meeting – March, 9 2011

  6. Readout Right Readout Left Si detector 1st fanout, 2nd fanout V HDI HDI U z 12.9 mm 97.0 mm CDR design is being revised for TDR! Layer 0 striplets design (Lab.) Geometrical acceptance: 300 mrad both in FW and BW Distance from the i.p. : R=15 mm Choosing an Octagonal shape: - Module active area = 12.9 x 97.0 mm2 (includes 4% area overlap for alignment) - double sided Si detector, 200 mm thick with striplets (45o w.r.t det. edges) readout pitch 50 mm - multi-layer fanout circuits (similar to SVT modules, z side) are glued on each sensor, connecting Si strips to Front End Electronics (fanout extends twice wider than the detector, to allow a minimum of 50 mm between metal traces ~ 700 strip/readout side!). • In a module needed ~2 fanouts/side ! • A new readout chip is needed to cope with the high background rate (up to 200 MHz/cm2) r= 15 mm Conceptual design module “flat” SVT Mechanics Meeting – March, 9 2011

  7. Already at the time of the CDR, it was clear that: • the striplet det’s required a fan-out circuit of some complexity to take out the signals from so many strips (768). • not negligible X0 contribution (45um Si-eq/f.o. layer) • to fit the geometrical constraints, the L0 module must use the f.o. extension to bend at a higher radius and to be connected with a transverse hybrid SVT Mechanics Meeting – March, 9 2011

  8. BaBar SVT For the SuperB SVT L1-L5 we start from the BaBar configuration SVT Mechanics Meeting – March, 9 2011

  9. The BaBar Silicon Vertex Tracker • 5 Layers of double-sided, AC-coupled Silicon. • Custom rad-hard readout IC (the AToM chip). • Low-mass design. ( Pt < 2.7 GeV/c2 for B daughters) • Stand-alone tracking for slow particles. • Inner 3 layers for angle and impact parameter measurement. • Outer 2 layers for pattern recognition and low Pt tracking. 20 cm 30 cm 40 cm SVT Mechanics Meeting – March, 9 2011

  10. Space Frame and Support Cones SVT Mechanics Meeting – March, 9 2011

  11. SVT Geometry LayerRadius 1 3.3 cm 2 4.0 cm 3 5.9 cm 4 9.1 to 12.7 cm 5 11.4 to 14.6 cm Be Beam pipe 1.0 % X0 10 cm (Arched wedge wafers not shown) SVT Mechanics Meeting – March, 9 2011

  12. SVT Mechanical Features Brass cooling rings Carbon fiber Space Frame 22 cm B1 dipole permanent magnet (inside support cone) B1 dipole permanent magnet (inside support cone) Carbon fiber support cones 109 cm SVT Mechanics Meeting – March, 9 2011

  13. SVT Mechanical Features Silicon wafers Carbon & Kevlar fiber support ribs SVT Mechanics Meeting – March, 9 2011

  14. BaBar SVT SVT complete half SVT SVT Mechanics Meeting – March, 9 2011

  15. SVT BaBar Modules Number of Wafers Total Phi-Strip Length Backward Forward Layer Z-Strip Length 5b 8 26.5 cm 26.5 cm 4.1 to 5.1 cm 5a 8 26.5 cm 25.1 cm 4.2 to 5.1 cm 4b 7 22.4 cm 19.9 cm 4.2 to 5.1 cm 4a 7 22.4 cm 18.5 cm 4.2 to 5.1 cm 3 6 12.8 cm 12.8 cm 7.0 cm 2 4 8.8 cm 8.8 cm 4.8 cm 1 4 8.2 cm 8.2 cm 4.0 cm SVT Mechanics Meeting – March, 9 2011

  16. SVT SuperB Modules (first guess!) SVT Mechanics Meeting – March, 9 2011

  17. SVT Mechanics Meeting – March, 9 2011

  18. Fanouts Fanout circuits provide electrical connections between the detector strip and the front-end chip Properties: Cu (Cr and Au) layer on an Upilex substrate (50 mm thick, < 0.03%X0) C = 0.52 pF/cm R = 2 W/cm SVT Mechanics Meeting – March, 9 2011

  19. SVT Module / Layer: L 1-2 : 6 L 3 : 6 L 4A+B: 8 + 8 L 5A+B: 9 + 9 SVT Mechanics Meeting – March, 9 2011

  20. L0/SVT mech. Specifications Difficult at this stage to have an IR design frozen to perform a realistic mechanical design of L0 and SVT : Anyway, now, there are some constraints that force the design : A) L0 and SVT design should allow a quick demounting from the IR. B) L0 must be mounted on the Be beam pipe to avoid any possible relative movement (low clearance from beam pipe). C) SVT is independent from beam pipe and supported on the QD0 criostat. SVT Mechanics Meeting – March, 9 2011

  21. L0/SVT specification SVT demounting means to spilt it in two half near I.R., so SVT structure has to be very rigid to assure good stability and also it is necessary a mechanical equipments that is able to support the two SVT halves just beside of Be pipe and, also, able to reassemble them after L0 replacement . SVT Mechanics Meeting – March, 9 2011

  22. L0/SVT specification Cooling system, cables and any system service of SVT has to be independent from any L0 component, allowing a complete independent demounting. If we assume a support structure with two semicone support, (BaBar like), we need a rigid space-frame structure to be redesigned SVT Mechanics Meeting – March, 9 2011

  23. Mechanical Design Items Current work in Pisa : • Central Be pipe and cooling • L0 Stripletsmodule design and supports SVT Mechanics Meeting – March, 9 2011

  24. Mechanical Design Items Current work in Pisa: • L0 pixel module design and supports • IR solid modelling ( on M.Sullivan indications) I.P. SVT Mechanics Meeting – March, 9 2011

  25. Mechanical Design Items Current work in Pisa: • Quick demounting of L0/SVT • SVT geometrical layout of layer 1-5 modules 13mm ? 300mrad 350mrad SVT Mechanics Meeting – March, 9 2011

  26. Mechanical Design Item Itemsnotcovered: • Layer1-5 detailedModule design • SVT semiconesupportStructure and HDI cooling design • Space Frame structure design • Mechanichalequipmentfor SVT split . • (Work on theseitemscould start assoonasgeometrical layout oflayer 1-5 moduleshasbeendefined ). SVT Mechanics Meeting – March, 9 2011

  27. Engineering /Technical Man Power Actually in Pisa: • 0.7 fte senior mechanical engineer • 0.7 fte draftman Starting beginning of April: • 1 fte young mechanical engineer • Technical staff: • H.T. labs facilities and 2-3 expert technicians from High Technologies technical group for electronics and mechanical prototype preparations . SVT Mechanics Meeting – March, 9 2011

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