The evolution of Vertex Detectors The evolution of Vertex Detectors From Gas to Silicon Strips From Gas to Silicon Strips Better and better Silicon Strips Better and better Silicon Strips From Strips to (Fast, Micro) Pixels From Strips to (Fast, Micro) Pixels (From Of f - - line Vertex to On line Vertex to On- - line Track Seeding) line Track Seeding) (From Of f Bigger and bigger Silicon Strip systems: Bigger and bigger Silicon Strip systems: From Strip Vertex detectors, to Strip Trackers From Strip Vertex detectors, to Strip Trackers Marcello Mannelli The evolution of Vertex Detectors The evolution of Vertex Detectors Siena October 2001
From Wire Chamber to Silicon Strips From Wire Chamber to Silicon Strips Upgraded to become better & better, Upgraded to become better & better, The 4 LEP experiments started with gas chambers, The 4 LEP experiments started with gas chambers, Bigger & bigger Bigger & bigger both f or tracking and vertex reconstruction. both f or tracking and vertex reconstruction. The 4 LEP installed Silicon Strip Vertex The 4 LEP installed Silicon Strip Vertex Detectors, either single or double- sided, Detectors, either single or double sided, Aleph 1998 Aleph 1998 within a couple of years of LEP startup within a couple of years of LEP startup These opened the way f or These opened the way f or precision b precision b- physics at LEP physics at LEP Delphi 1998 Delphi 1998 Aleph 1991 Aleph 1991 Marcello Mannelli The evolution of Vertex Detectors The evolution of Vertex Detectors Siena October 2001
Better and better Silicon Vertex detectors Better and better Silicon Vertex detectors Very low mass systems Very low mass systems Use double sided sensors Use double sided sensors Where ever possible Where ever possible Highly specialized Geometries: Highly specialized Geometries: Very light mechanical structure Very light mechanical structure CF, Be space f rames et c CF, Be space f rames et c Very light electrical services, Very light electrical services, Material displaced outside Material displaced outside Fiducial acceptance region Fiducial acceptance region There are examples There are examples Of this in every HEP lab: Of this in every HEP lab: More and more imaginative names: More and more imaginative names: CLEO, Babar, Belle… CLEO, Babar, Belle… LHCb VELO: LHCb VELO: VErtex LOcater VErtex LOcater CDF, D0… CDF, D0… Marcello Mannelli The evolution of Vertex Detectors The evolution of Vertex Detectors Siena October 2001
Pixel Vertex detector f or the LHC Pixel Vertex detector f or the LHC With this cell size occupancy is ~ 10 - 4 The region below 20cm is inst rument ed The region below 20cm is inst rument ed With this cell size occupancy is ~ 10 with Silicon Pixel Vertex systems with Silicon Pixel Vertex systems This makes Pixel seeding the f astest This makes Pixel seeding the f astest Starting point f or track reconstruction Starting point f or track reconstruction Despite the extremely high track density Despite the extremely high track density The Pixel area is driven by FE chip The Pixel area is driven by FE chip Shape dif f erently optimized f or resolution Shape dif f erently optimized f or resolution resolution ~ 20 µ m I P I P . resolution ~ 20 2 2 ATLAS ~ 50 * 400 mm ATLAS ~ 50 * 400 mm trans. trans f or tracks with P f or tracks with P t ~ 10GeV ~ 10GeV CMS ~ 150 * 150 mm 2 CMS ~ 150 * 150 mm t 8 10 7 pixels 2m 2 , 2m 2 , 8 10 pixels The ATLAS Pixel Vert ex The ATLAS Pixel Vert ex The CMS Pixel Vert ex The CMS Pixel Vert ex 4 10 7 pixels 4 10 pixels Three disk layers 3 3 0 0 c c m m 93 cm 93 cm Three barrel layers Marcello Mannelli The evolution of Vertex Detectors The evolution of Vertex Detectors Siena October 2001
Pixel Vertex detectors f or the LHC Pixel Vertex detectors f or the LHC Highest radiation environment: Highest radiation environment: Specif ic program of sensor R&D Specif ic program of sensor R&D – Partial depletion, despite High V Partial depletion, despite High V bias – bias n- on on- n technology n technology – The “back The “back- side” of a double side” of a double- sided sensor sided sensor • Uses much of that know Uses much of that know- how how • Specif ic issues: Specif ic issues: • P- stop design to ensure stop design to ensure pixel biasing & isolation pixel biasing & isolation Open p Open p- stop, “p spray” … stop, “p spray” … Oxygenated bulk may allow Oxygenated bulk may allow – lower bias voltage operation, lower bias voltage operation, especially f or charged hadron especially f or charged hadron induced damage (dominant) induced damage (dominant) Marcello Mannelli The evolution of Vertex Detectors The evolution of Vertex Detectors Siena October 2001
PI XEL CHI P WI TH FI NAL ARCHI TECTURE: CMS PI XEL CHI P WI TH FI NAL ARCHI TECTURE: CMS ( submitted Aug. / Sept 2000 in DMI LL ) ( submitted Aug. / Sept 2000 in DMI LL ) DM_PSI 41 • ~50% pixels of f inal 52x53 pixel ROC ~50% pixels of f inal 52x53 pixel ROC f inal Column Drain Architecture f inal Column Drain Architecture • - f ast hit scanning mechanism (>GHz) f ast hit scanning mechanism (>GHz) - double hit capability during DC scan double hit capability during DC scan f inal f inal Double Column Periphery Double Column Periphery • - 8 timestamp buf f ers / double column 8 timestamp buf f ers / double column 8. 4mm 8. 4mm - 24 pixel data buf f er / double column 24 pixel data buf f er / double column test chip with 36x40 pixels (~240K transistors) test chip with 36x40 pixels (~240K transistors) • - L1 trigger delay up to 255 bunch crossing L1 trigger delay up to 255 bunch crossing f inal f inal Analog Readout Chain Analog Readout Chain • - 6 clock cycles per pixel hit 6 clock cycles per pixel hit - analog coded column & pixel address analog coded column & pixel address - analog readout of pixel pulse height analog readout of pixel pulse height • missing missing Control & I nterf ace Block Control & I nterf ace Block !! !! - DAC’s DAC’s, Voltage Regulators, f ast I 2C etc. , Voltage Regulators, f ast I 2C etc. Marcello Mannelli The evolution of Vertex Detectors The evolution of Vertex Detectors Siena October 2001
Noise and Threshold unif ormity: ATLAS Noise and Threshold unif ormity: ATLAS Mean Threshold ~3200 e Bef ore tuning: threshold dispersion = 290 e Af ter tuning: threshold dispersion = 190 e Marcello Mannelli The evolution of Vertex Detectors The evolution of Vertex Detectors Siena October 2001
Status of ATLAS & CMS Pixel Vertex Systems Status of ATLAS & CMS Pixel Vertex Systems Module hybridization is well advanced Module hybridization is well advanced Both collaborations have developed FE chips Both collaborations have developed FE chips (including high yield bump (including high yield bump- bonding) bonding) with f ull f unctionality (or close to it) with f ull f unctionality (or close to it) Flex MCC Hybrid Reliable Reliable rad rad- hard implementation is hard implementation is critical critical sensor bumps Honeywell SOI no longer available Honeywell SOI no longer available FE chip FE chip C- C support Unexpected yield problem with DMI LL: Unexpected yield problem with DMI LL: requires re requires re- design of t he ATLAS circuit design of t he ATLAS circuit Concerns a f eature not used in CMS design Concerns a f eature not used in CMS design CMS August ’00 submission: CMS August ’00 submission: f unctionality ~ OK, Yield? f unctionality ~ OK, Yield? Engineering Run winter 01 Engineering Run winter 01- 02: 02: Determine yield, build f ull size modules Determine yield, build f ull size modules ATLAS has made a f irst pixel chip ATLAS has made a f irst pixel chip submission in 0. 25mm I BM technology submission in 0. 25mm I BM technology CMS is preparing such a submission CMS is preparing such a submission ATLAS Flex hybrid, bump bonded module For spring 2002 For spring 2002 Marcello Mannelli The evolution of Vertex Detectors The evolution of Vertex Detectors Siena October 2001
From strip Vertex to strip Tracking From strip Vertex to strip Tracking Single Single- sided, AC coupled, polysilicon biased sensors have become a matu sided, AC coupled, polysilicon biased sensors have become a mature re technology technology Costs have decreased, and large scale production is now possible Costs have decreased, and large scale production is now possible (10 5) 5) channels High level of expertise f or FE I C design and system aspects of O High level of expertise f or FE I C design and system aspects of O(10 channels Move to detectors with a high level of independent tracking capa Move to detectors with a high level of independent tracking capability bility A f ew m 2 : ⇒ A f ew m CDF CDF – D0 D0 2 : ⇒ Several * 10 1 m Several * 10 ATLAS ATLAS ⇒ A couple * 10 2 2 : 2 A couple * 10 m CMS CMS Marcello Mannelli The evolution of Vertex Detectors The evolution of Vertex Detectors Siena October 2001
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