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Silicon Tracker for CBM

Silicon Tracker for CBM. Walter F.J. Müller , GSI, Darmstadt for the CBM Collaboration Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway, 4-6 April 2005. CBM Setup.  Radiation hard Silicon pixel/strip detectors in a magnetic dipole field

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Silicon Tracker for CBM

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  1. Silicon Tracker for CBM Walter F.J. Müller, GSI, Darmstadt for the CBM Collaboration Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway, 4-6 April 2005

  2. CBM Setup  Radiation hard Silicon pixel/strip detectorsin a magnetic dipole field  Electron detectors: RICH & TRD & ECAL: pion suppression up to 105  Hadron identification: RPC, RICH  Measurement of photons, π0, η, and muons: ECAL Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  3. CBM Physics Topics and Observables • In-medium modifications of hadrons onset of chiral symmetry restoration at high ρBmeasure: , ,   e+e- (μ+ μ-) open charm: D0, D± • Strangeness in matter enhanced strangeness productionmeasure: K, , , ,  • Indications for deconfinement at high ρB anomalous charmonium suppression ?measure: D0, D± J/  e+e- (μ+ μ-) • Critical point event-by-event fluctuations measure: π, K Dalitz and conversion rejection Vertex detector V0 reconstruction Low cross sections→ High interaction rates→ Selective Triggers Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  4. Silicon Tracker in CBM – The Mission • track reconstruction for all charged particles • above 0.1 GeV/c • with a resolution of 1% at 1 GeV/c • primary and secondary vertex reconstruction with a resolution good enough to efficiently trigger on and reconstruct open charm (D0, D±) • V0 track pattern recognition for reconstruction of weak decays of hyperons (K0s,Λ,....,Ω) Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  5. A Typical Au+Au Collision Central Au+Au collision at 25 AGeV: URQMD + GEANT 160 p 170 n 360 -330 +360 0 41 K+ 13 K-42 K0 ~500 charged primaries inacceptance (50-500 mrad) → high granularity Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  6. Open Charm Reconstruction Some hadronic decay modes D(c = 317 m): D+  K-++ (9  0.6%) D0(c = 124.4 m): D0  K-+ (3.9  0.09%) D0→K-p+ Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  7. Meson Production in central Au+Au W. Cassing, E. Bratkovskaya, A. Sibirtsev, Nucl. Phys. A 691 (2001) 745 SIS300 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  8. Rates and Doses for Open Charm • Assume • 10-5 D / central collision (for 15 A GeV) • 4% branching ratio (for D0  K-+) • 50% geometrical acceptance • 5% reconstruction efficiency • → 10-8 detected D / central collision • Estimate Rates • 107 collisions/sec • 50% duty cycle • → 1000 D/day • Estimate Doses • Flux: 3.2 108 part/cm2/sec at z=5cm Θ=100 mrad • 1015 part/cm2 or 30 Mrad in a 10 week run Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  9. 1st Guess on Geometry Strip • Acceptance: 50 to 500 mrad • Magnet: ~ 1 Tm bending power ~ 1 m field length 1 x 1 m aperture • 1st plane: z=5cm ; size 25 cm2 covers 100 to 500 mrad • last plane: z=100cm; size 1 m2 • assume 7 planes • 3 or 2 pixel • 4 or 5 strip Pixel z = 5,10,(20) cm z = (20),40,60,80,100 cm mostly guided byopen charm needs Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  10. Possible Configuration of 1st+2nd Plane • Inspired by BTeV • Detectors can be moved in two halfs • Remove sensors from beam during focusing • Only two module geometries • 1st plane and inner part of 2nd plane should be replaceable after a run Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  11. Vertex Detector: The MAPS Option I Monolithic Active Pixel Sensors • Pros: • done with commercial CMOS process • sensor thickness below 100 μm  • pixel pitch 20-35μm  • resolution 3 μm  • Under work: • fast column based readoutultimate speed: ~ 5 μs frame time • radiation hardnesscurrently: 1 Mrad • CBM related MAPS R&D in 2005: • MIMOSA 11: radiation tolerance • MIMOSA 13: current readout MIMOSA IV IReS / LEPSI Strasbourg Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  12. Vertex Detector: The MAPS Option II Double layer to cover insensitive areas First material budget assessment 0.29 % by M. Deveaux Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  13. 1st Guess for Strip Tracker I 4 Strip tracking stations Tracking Stations Nr. 4 and 6 Double sided Si-Strip detectors: thickness 100 μm pitch 25 μm Stereo angle 15o Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  14. Basic Elements: Inner : 6x4 cm Middle : 6x12 cm Outer : 6X20 cm 1st Guess for Strip Tracker II Tracking Station Nr. 6 +40 cm +4cm - 4cm • Open questions: • strip length(reduce fake hits) • location of read-out(all at edge ?) -40 cm by V. Saveliev Read out Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  15. D0 K-,+signal Background Reconstructed events Z-vertex(cm) D0 Reconstruction I • Assume: • 100 μm pixel layers • 200 μm strip layers Au+Au 25 A GeV IP cut Z vertex cuts optimized for significance Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  16. D0 Reconstruction II • Assume: • 107 interactions/sec • 1% momentum resolution effective Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  17. Impact of Resolution and Thickness I • Study 3 cases: • MAPS: 100 μm thickness 10 μm resolution • 'fine-pitch' Hybrid 700 μm thickness 35 μm x 35 μm pixel • 'normal' Hybrid 700 μm thickness 50 μm x 350 μm pixel Signal: D  K-π+ by I. Vassiliev Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  18. Impact of Resolution and Thickness II • Study 3 cases: • MAPS: 100 μm thickness 10 μm resolution • 'fine-pitch' Hybrid 700 μm thickness 35 μm x 35 μm pixel • 'normal' Hybrid 700 μm thickness 50 μm x 350 μm pixel D0 efficiency 5.10 %  1.70 %  0.01 % • Conclusion: • 700 μm material budget tolerable • conventional sized (~20000 μm2) hybrid pixel detectors are excluded UrQMD (combinatorial background) • Note:The dose required for a physics signal increases with decreasing D0 efficiency. Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  19. Tracking I • All is fine if • perfect detector response • no event pile-up in pixels • no fake hits in strips • The full MC environment with realistic digitizers is just beginning to be productive • event pile-up in pixel causes trouble • fake hits in strips cause trouble • in a nutshell: • forward tracking hampered by pile-up • backward tracking hampered by fakes • need a clean track seed somewhere.... • apparently needed (choose one or more): • more planes, more views • shorter strips • fast pixel with clean event association Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  20. Proposal I Strip(x,u and y,v) Pixel Strip (r,f) Could be like LHCb-VELO Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  21. Proposal II Strip Hybrids MAPS High resolution tracking with large coverage Ultimate vertex resolution Should deliverunambiguous seeds Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  22. STS is a 'Trigger' Detector I • STS is the essential (and possibly only) device used for first level online event selection (a.k.a. L1 trigger) decision for open charm candidates. • Problem similar to LHCb or BTeV • Very fast online tracking needed • 107 interactions/sec → 1.5 109 tracks/sec • Robust tracking needed • confusion in 1st or 2nd plane gives detached tracks... • Speed and robustness of a fast online tracking is thus an essential criterion • This might require • 'simple geometry' • clear event association • additional redundancy Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  23. STS is a 'Trigger' Detector II • STS provides information for first level event selection • self-triggered FEE – there is no L0.... • high-bandwidth readout - all hits are send • see talk tomorrow.... Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  24. Low Mass Dilepton Spectroscopy I • CBM has PID after tracker • → avoid conversions in tracker (low mass) • → reconstruct conversions and Dalitz decays Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  25. .. those will form a fake open pair If these are notreconstructed .. Low Mass Dilepton Spectroscopy II • Likely we need • additional coverage • more redundancy • an adapted geometryfor dilepton runs tracking efficiencydown to 0.1 GeV/cimportant to suppressbackground Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  26. 25 AGeV Au->Au 0.25mm Geant3 Formula Relative d-electrons – Atomic Physics Background • Large cross section for high energetic (> 10 MeV) knock-on electrons. • In 1st station: • 5 per Au ion passing 1% target • 500 per min. bias interaction • compare: ~150 charged hadrons Geant 3 vis PhysRev D V.54/1 p.134 by P. Koczon Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  27. Summary • Vertex tracker: • 700 μm material budget tolerable • about 35 μm x 35 μm pixel size needed • only a small part (50 cm2) is exposed to very high dosesreplacing this part after a major D run is feasible • required dose and also interaction rate depends on D0 efficiencythin detectors (100 μm) require significantly less than thick (700 μm) ones • fast readout allowing clear event association very valuable (at least) • THUS WANTED: • thin (<700 μm) • high resolution (σ ~ 10 μm) • fast (best <100 ns) • radiation tolerant (30, better >100 Mrad) • self-triggered, high bandwidth FEE Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  28. Summary II • Vertex tracker (cont.): • possible new scenarios from this workshop: • 50 μm x 50 μm hybrid pixel • Synergy from rad-hard sensor development • improving resolution beyond pixel/sqrt(12) be very helpful • definitively new readout chip needed • channel density and low power requirements challenging • radiation hardness probably o.k. with DSM CMOS (100 Mrad) • DEPFET array • challenge here: • high speed readout Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  29. Summary III • Strip tracker: • 100 to 150 μm double sided sensor detailed impact of material budget on physics performance yet to be studied in detail. • rad-hard sensors (10 Mrad, should last 10 years) • strip geometry will certainly evolve • shorter strips • additional planes/views • Can the readout be placed at the sides ? (cooling, material budget,...) • Again: Self-triggered, high bandwidth readout chip needed • has to handle hits at random times (not a collider experiment....) • best feasible time resolution to help event identification Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  30. Summary IV • Many challenges for sensor and readout • Timelines: • Technical Proposal: end 2006 • Technical Design Reports: end 2009 • Open for collaboration with all interested parties Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  31. CBM and HADES All you want to know about CBM:Technical Status Report (400 p)now available under http://www.gsi.de/documents/DOC-2005-Feb-447-1.pdf Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  32. CBM R&D working packages FEE, Trigger, DAQ Design & construction of detectors Feasibility studies Simulations Framework GSI Silicon Pixel IReS Strasbourg Frankfurt Univ., GSI Darmstadt, TRD (MWPC) JINR-LHE, Dubna GSI Darmstadt, Univ. Münster NIPNE Bucharest ,ω, e+e- Univ. Krakow JINR-LHE Dubna GSI Darmstadt KIP Univ. Heidelberg Univ. Mannheim Uni. Kaiserslautern GSI Darmstadt JINR-LIT, Dubna Univ. Bergen KFKI Budapest Silesia Univ. Katowice Warsaw Univ. PNPI St. Petersburg NIPNE Bucharest MEPHI Moscow Wuhan Univ. Tracking KIP Univ. Heidelberg Univ. Mannheim JINR-LHE Dubna JINR-LIT Dubna Silicon Strip Moscow State Univ MEPHI, Moscow CKBM St. Petersburg KRI St. Petersburg Univ. Obninsk J/ψ e+e- INR Moscow GSI RBI Zagreb TRD (straw) JINR-LPP, Dubna FZ Rossendorf FZ Jülich Tech. Univ. Warsaw Ring finder JINR-LIT, Dubna J/ψμ+μ- PNPi St. Petersburg SPU St. Petersburg ECAL ITEP Moscow IHEP Protvino RPC-TOF LIP Coimbra, Univ. Santiago Univ. Heidelberg, GSI Darmstadt, NIPNE Bucharest INR Moscow FZ Rossendorf IHEP Protvino ITEP Moscow RBI Zagreb Univ. Marburg Korea Univ. Seoul π, K, p ID Heidelberg Univ, Warsaw Univ. Kiev Univ. NIPNE Bucharest INR Moscow D  Kπ(π) GSI Darmstadt, Czech Acad. Sci., Rez Techn. Univ. Prague IReS Strasbourg RICH IHEP Protvino GSI Darmstadt Pusan Univ. PNPI St. Petersburg Magnet JINR-LHE Dubna GSI Λ, Ξ,Ω PNPi St. Petersburg SPU St. Petersburg JINR-LHE Dubna δ-electrons GSI Darmstadt beam det. Univ. Mannheim GSI Darmstadt Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

  33. The End Thanks for your attention Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI

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