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Introduction to VELO Upgrade

Introduction to VELO Upgrade. LHCb VELO Upgrade electronics meeting 7 th -8 th December 2010 Paula Collins. Charm samples similar to B factories. LHCb : A great start!. Very clean signals in low and high multiplicity B decay channels. Clear CP violation in raw data!. Electroweak

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Introduction to VELO Upgrade

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  1. Introduction to VELO Upgrade LHCb VELO Upgrade electronics meeting 7th-8th December 2010 Paula Collins LHCb VELO Upgrade Electronics Meeting

  2. Charm samples similar to B factories LHCb: A great start! Very clean signals in low and high multiplicity B decay channels Clear CP violation in raw data! Electroweak physics LHCb VELO Upgrade Electronics Meeting

  3. LHCb upgrade : The Opportunity • LHCb is designed to run at a fraction of the luminosity of the • GPDs by tuning down b* / shifting beams • Luminosity 2.1032 • Crossings with ≥ 1 interaction 10 MHz • Average number of interactions per crossing 1.2 • Accumulate 1-2 fb-1per year for 5 years 4 • LHCb will be upgraded during 2015/2016 to run at 5-10 times greater luminosity and double the hadronic trigger efficiency • Independent of LHC/SLHC upgrade • Accumulate -> 20 x statistics • Accumulate 1-2 fb-1per year for 5 years • Can we run at the larger pile-up? We already did! With machine partially filled (344) bunches, we have been running at upgrade occupancies already 20 1032cm-2s-1 3 events / crossing 2 events/crossing ≤2 ≤4 ≤6 10 1032cm-2s-1 1 Current 2 1032cm-2s-1 0 2 5 10 15 20 Luminosity (1032cm-2s-1 ) LHCb VELO Upgrade Electronics Meeting

  4. LHCb Upgrade – The Motivation LHCb – Precision Experiment • Bs→J/yfCP violating phase: SM error in 2 fb-1, precision measurement in 50 fb-1 • Angular asymmetries in Bo→K*om+m-. • BS→m+m- very sensitive to SUSY effects: 3s possible around 2 fb-1, precision measurement in 50 fb-1 • Tree level g measurement – 4-5o in 2 fb-1, 1o in 50 fb-1 LHCb – Discovery Experiment • Angular coverage very complementary to ATLAS and CMS • Long VELO allows us to measure long lived particles • Exotic particle searches, non SM Higgs…. LHCb VELO Upgrade Electronics Meeting

  5. LHCb Upgrade Strategy – stay flexible! We do not know how the physics case will evolve at the end of 2011 But we know that our current trigger has a bottleneck at 1 MHz • MOVE to a fully software based trigger! • All electronics must be redesigned to zero-suppress data and transfer events @40MHz to a massive CPU filter farm ! • (For 10 1032cm-2s-1 , we can still use the current L0 hardware trigger with relaxed thresholds to limit event rate to 5MHz) • Complete replacement of VELO and HPDs. LHCb VELO Upgrade Electronics Meeting

  6. Current VELO is doing a great job!Why upgrade? • Experiment has operated up to m=2.6 pretty successfully • VELO itself is showing a superb performance • Noiseless operation • Excellent resolution • Good Pattern Recognition • Best impact parameter resolution at LHC T Ruf, R. McNulty

  7. Dose after 100 fb-1 500 neqcm-2 x 1016 TID (MRad) 7 mm 50 5 Radius (cm) Reason 1 : Severe Irradiation Damage At 7 mm from beam we accumulate 370 MRad or 8 x 1015 neq/cm2. Recent RD50 studies have shown that silicon irradiated at these levels still delivers a signal of ~ 8ke- / MIP Distance from silicon tip to thermal connection too great Efficient heat removal mandatory to avoid thermal runaway! Diamond cooling substrate candidate solution Electronics must be of sufficiently low noise to cope with reduced signal

  8. Reason 0 It’s the trigger, stupid • Electronics has to digitise, zero suppress and transmit event data at 40 MHz • By pixel standards the occupancy of the VELO is miniscule, but the data rate is HUGE • 1 chip has to transmit 10-20 Gbit / second • Our current granularity, occupancies = ok but FE electronics and DAQ are not

  9. All Change for the VELO? • No! Can reuse • Vacuum vessel • Motion system – as much as possible • LV and HV systems • CO2 cooling plant • What’s new • Module • Cooling interface • RF foil • Readout infrastructure This object and the challenge of reading It out is the subject of the next few days discussion LHCb VELO Upgrade Electronics Meeting

  10. Q Conversion by time-over-threshold ToT = f(Q) TimepixVELOPix • Why we Timepix (and Timepix2) • The square pixel (55um x 55um) gives equal spatial precision in both directions, removing the need for a double sided modules and saving a factor 2 in material. • IBM 130 nm CMS process • the extremely low occupancy (< 2 ppm) environment is ideally suited to the time-over-threshold conversion, as the efficiency will not suffer from the relatively large (1us) dead time. • It has great radiation hardness potential and very small periphery • It is a very economic way (power&space) to obtain >6 bit digitization Comparator threshold Comparator output • What we need to change LE TE • replace ‘shutter’ based acquisition/readout scheme by continuous, dead-timeless operation. • sustained readout of pixels with maximal average particle flux = 5 particles/cm2/25 • power consumption must stay within1-2 W • pixel functionality: • reduce TOT count range and resolution : 4 to 6 bit scheme is sufficient. • reduce rise time to reduce time-walk effects. • add bunch identification to hit. ToT = TE - LE

  11. Challenge of the foil • Foil construction one of the major achievements of current VELO • 8 year R&D project at Nikhef to manufacture leak tight 03 mm AlMg3 foil of correct dimensions • For the upgrade foil design will be critical • CFRP composite option • Low density, space qualified, possibility of reinforcement with carbon nanotubes, single integrated unit • Metal alloy option • Focus on fabrication technique : possibility of machining using 5-axis milling machine • Fabrication work in collaboration with CMA (composite Mirror Applications) • Challenges include • Uniformity of thickness and stiffness • Vacuum tightness • Must be compatible with ultra high vacuum and dynamic beam effects i.e. NEG coating • RF shielding capabilities • Irradiation resistance • Incorporate compound curvatures of L shape option LHCbVelo Upgrade Electronics Meeting

  12. Sensor R&D • Planar silicon • Things are looking up for charge collection, especially for thin sensors • R&D focussing on guard rings • Irradiation of planar silicon + Medipix3 planned • Diamond • Exciting option for removing thermal runaway headache • Very radiation hard • Double act: sensor and thermal path • 3d sensors • Super radiation hard • Many Medipix/Timepix assemblies available

  13. Strip Option • In case the material budget/power consumption of the pixel option falls beyond specifications or time limits, a backup strip option is being prototyped. • Key points: • Optimisation of strip capacitance to bring down noise • Cooling simplified • Possible move to “spider web” – simplified pattern recognition • Increase in number of strips and better layout – expected occupancy at upgrade will be 0.5% • IP resolution superior to pixels • New chip needed (synergy with IT) Pixels Strips

  14. Infrastructure • Critical for Upgrade R&D • Laser test stand already used extensively for timepixcharacterisation • Vacuum chamber construction underway • Module0 prototypes to be produced and irradiated in coming months • Testbeam capability • Timepix based telescope constructed and operated for LHCb upgrade in collaboration with Medipix group • Has already produced fantastic results and is a key tool • Will be discussed in this meeting

  15. Schedule • Current machine schedule fluctuating • Regular 4 month shutdowns anticipated • Possible VELO related inverventions ~ 4 months • Longer shutdowns for LHC related interventions • Triplet replacement, Linac4 etc. • GPD upgrades staged, with larger interventions to synchronise with machine – preferably after 200 fb-1 • LHCb upgrade installation – 2016/2017 • Module production to start in 2013

  16. Module Prototyping milestones • Up to mid 2011 • Demonstrator staves and modulesin three types • Mechnical type • With CVD diamond • Or another cooling solution • Electronics type • With metallisation on dimaond • With flex • Cooling connection demonstrator • Suitable pipe and attachments • Different gluing options, number of pieces of silicon etc. • Early 2012 • 12 chip module with Timepix II and protoype sensor • Mechanical, thermal, outgassing, metrology testing • Irradiation tests • Late 2012 • 12 chip module with final components • Full characterisation

  17. Other milestones • Chip available in 2012 • Implying not only electronics design effort but also prototyping and qualification in testbeam • Sensor technology decision on same timescale • Module cooling structure decision mid 2011 • Module geometry should already be final • Optical/Copper signal chain decision this meeting • Mechanical structure finalised end 2011

  18. Production tasks Are there institutes to take on these tasks? • Production is almost on us and must be well prepared • Wafer probing • Sensor testing • Bump bonding • Dicing, thinning, metallisation • Flip chip assembly, inspection • Bare module probing • Module assembly – mechanical, wire bonding • Assembled module testing • Optical interface tests • Supporting DAQ, cooling systems • Databases • Irrradiation tests • Metrology • Transport jigs • QA plan • ….

  19. Strawman Layout Organisation in 2010, As presented on VELO Upgrade web page CO2 vs LN2 cooling choice Chip Readout and Link Integration (Jan) Module Cooling Structure and hybridisation options Link Technology Planar Silicon option Diamond sensor option 3d sensor option Module 0 construction (Marina) Simulation software Electronics R&D Infrastructure Foil R&D Goes to TT Replacement needed (arrows are indicative) Strip Option

  20. Strawman Layout Marco Gersabeck CO2 vs LN2 cooling choice Steve Blusk Module Cooling Structure and hybridisation options Val O’Shea and Tony Smith Link Technology Dave Bailey Planar Silicon option GianluigiCasse Diamond sensor option Marina Artuso 3d sensor option Chris Parkes Simulation software Tomasz Skwarnicki Electronics R&D Ken Wyllie Infrastructure Richard Plackett Foil R&D Ray Mountain Abraham Gallas Strip Option

  21. Organisation at time of LOI submission: • VELO Upgrade Institutes: • USC • Nikhef • Glasgow • CERN + Lausanne • Syracuse • Liverpool • Warwick • Manchester • Bristol • Erlangen • + New from now: Oxford • Changes Needed: • Module 0 convenor • More focus needed on cooling options • +… LHCb VELO Upgrade Electronics Meeting

  22. Rough cost estimates Velo is constructed with ~ 25 stations Each station has 2 modules, each module contains 2 hybrids of 6 chips on one piece of ~ 12 cm square silicon + one piece 12 cm square optical grade diamond About 1000 data links for the whole VELO and 50 Tell40s LV and HV power supplies to be reused Vacuum tank to be reused New cooling system, foils, and bases Tell40 and long distance cables not included R&D, manpower, quality control, in-house assembly costs, testbeam verifications, system integration etc. etc. All not included System integration material costs could likely mount up to 0.5-1 MChf (based on experience of current VELO)

  23. New Material Costs (minimum)

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