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LHCb Upgrade Meeting – VELO Update. Recent Developments LOI Draft
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LHCb Upgrade Meeting – VELO Update • Recent Developments • LOI Draft • Written and illustrated by many people, and in particular: Marina Artuso, Marco Gersabeck, Steven Blusk, Tony Smith, Val O’Shea, Dave Bailey, GianluigiCasse, Chris Parkes, Ken Wyllie, Ray Mountain, Abraham Gallas, Richard Plackett and Jan Buytaert • 2011 Plans LHCb Upgrade Meeting 12/
Strawman design LHCb Upgrade Meeting Paula Collins
VELOPix • ASIC to be based on Medipix3/Timepix2 development • Occupancy is very small but data rate can reach 45 Gbit/s from one ASIC • Data driven readout • Super pixel structure employed to compress clustered data on matrix • Clustered hits share timestamp and location information • Aim to reach ~ 14 Gbit/s and use 4 4 Gbit/s serial drivers per chip 220um Significant work completed on both front end and digital readout architecture LHCb Upgrade Meeting Paula Collins
Readout Chain: See Oxford Workshop 8/12 • High Speed Cu Link in Vacuum • ‘best’ dielectric = Liquidcrystalpolymer ‘LCP’ • Loss factor (tanδ) = 0.002 and lowdielectric constant K ~ 2.9. (Kapton: 0.005 and 3.4) • Lowout-gassing and very radiation hard ‘mechanically’ (dielectricproperties must beverifiedstill). • SeeUltralam 3000 from Rogers corp • TELL 40 Data Processing • Data flow poses significant challenges • Much progress (Xavier Gremaud) LHCb Upgrade Meeting Paula Collins
2009/2010 saw significant Timepix Telescope developments • Angled planes to boost resolution • Progression in readout speed USB -> USB2 ->Relaxed • couple of frames per second to 52 fps plus much better synchronisation • TELL1 readout integrated LHCb Upgrade Meeting Paula Collins
Timepix data analysis • Calibration of chip under excellent control • Many lessons learned for Timepix2 design and necessary useful features for calibrating final chip • Two paper drafts circulating and 3 more in the pipeline Before Calibration After Calibration LHCb Upgrade Meeting Paula Collins
Interesting info for silicon nerds… • Very precise tracking allows us to probe all kinds of details within the pixel cells, allowing us to to • Identify delta rays • Investigate threshold effects • Measure pixel diagonal resolution • Measure timewalk • Measure efficiency etc. etc. LHCb Upgrade Meeting Paula Collins
A few highlighted results: Resolution as a function of angle for 10V data (close to depletion) 100V data (overdepleted) There is an enormous gain at lower voltage Possible advantage for VELO under investigation Resolution as a function of number of bits (shown for three different angles) Input to Timepix2/Velopix design 4 bits and above are safe 3 bits is close to resolution degradation LHCb Upgrade Meeting Paula Collins
More exotic devices Thin sensors: Direct comparison of 300 and 150 mm thick sensors in identical conditions 3d device: Detailed characterisation of 3d device and direct comparison to planar sensor. Irradiated sensor also evaluated LHCb Upgrade Meeting Paula Collins
Diamond results also available from another telescope experiment LHCb Upgrade Meeting Paula Collins
Things to Update for LOI: 1. Material Description • Currently not specified • Material scans exist – do they make enough sense to put into the LOI already? • Back of the envelope calculation by looking at the two major items which changed • Current VELO 21 modules: 2 x 300 mm silicon = 0.62% X0 • Pixel VELO 26 modules: • 400 mm diamond = 0.32% X0 • 150 mm silicon = 0.16% X0 • 150 mm chip = 0.16% X0 • 50 mm glue = 0.03% X0 • (60 mm kapton + 100 mm Al power + 17.5 mm Al signals) = 0.15% X0 over half the area • TOTAL: 7.4% X0 (but current simulation has only 200 mm diamond plane) • Current VELO: 300 um thick AlMg3 RF foild • Pixel VELO: Aims to halve foil thickness Expectation: Reduction of about 5% absolute material due to foil thickness reduction. Modules expected to give similar material LHCb Upgrade Meeting Paula Collins
Material Scans (Thanks to David Dossett) Pixel VELO Current VELO The numbers work out roughly according to expectation – but still checking that the reasons are reasonable LHCb Upgrade Meeting Paula Collins
Things to Update for LOI:2. Plot for Strip Backup Solution Plot to show that the occupancies are reasonable at lumi10 b. Plot to show that strip solution has excellent ip resolution LHCb Upgrade Meeting Paula Collins
pCVD Diamond substrates for module 0.0 Nucleation side Growth side LHCb Upgrade Meeting Paula Collins Thickness: 250 mm, Thermal Conductivity 1800 Wm-1K-1
Ready for Metallisation step Molex slimstack connector 1mm mated height LHCb Upgrade Meeting Paula Collins
Measurement goals • Cooling and readout of irradiateed sensors • Explore relevant technologies suited for final module • Module 0 is 1/3 of final “half module” • Thermal characterisation • Independently: • Check thermal conductivity of different diamond samples and irraditat PT100 with Manganin wire Thermal shield LHCb Upgrade Meeting Paula Collins
Chip, Sensor availability • Medipix 3 chips bump bonded at CNM to 200 mm thick sensors in collaboration with USC • Aim to use this for Module0 test and irradiation • Multi Project Wafer received at Liverpool in last few days • 150 mm n-in-p • 4 Medipix singles, 2 doubles with ganged pixels LHCb Upgrade Meeting Paula Collins
Strawman Layout CO2vs LN2 cooling choice Chip Readout and Link Integration (Jan) Module Cooling Structure Hybridisation Options Link Technology Sensor Technology Simulation software Module 0 construction (Marina) Electronics R&D Infrastructure Foil R&D Strip Option (arrows are indicative)
Conclusions • Velo Upgrade has exciting features • But we are facing a critical lack of manpower to achieve our goals • We need a module 0 coordinator to push through the prototyping LHCb Upgrade Meeting Paula Collins
Timepix Telescope plans at CERN • The Timepix chip is a 65k, 55 x 55 mm square pixel array on a 1.4 mm square • The Timepix arms will be angled to enhance charge sharing and boost the resolution • 2010 measurements indicate a 4 mm resolution per plane • The readout is shutter based so a careful design is needed to incorporate with a 40 MHz readout • We have worked on two systems to provide the necessary TDC information, and have an FPGA based TLU under development. We consider it very important to integrate this with the rest of the AIDA program • The hardware is based on the chip-sensor assemblies, and relaxed readout. Prototypes are in hand which are fully sufficient for all development work. Final versions are under order. • The possibility of hiring a postdoctoral student is under discussion LHCb Upgrade Meeting Paula Collins