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

4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI 2 CBM Setup  Radiation hard Silicon pixel/strip detectors in a magnetic dipole field  Electron detectors: RICH & TRD & ECAL: pion suppression up to 10 5  Hadron identification: RPC, RICH  Measurement of photons, π 0, η, and muons: ECAL

4-6 April 2006 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 ρ B  measure: , ,   e + e - (μ + μ - ) open charm: D 0, D ± Strangeness in matter  enhanced strangeness production  measure: K, , , ,  Indications for deconfinement at high ρ B  anomalous charmonium suppression ?  measure: D 0, D ± J/   e + e - (μ + μ - ) Critical point  event-by-event fluctuations  measure: π, K Low cross sections → High interaction rates → Selective Triggers Vertex detector V 0 reconstruction Dalitz and conversion rejection

4-6 April 2006 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 (D 0, D ± ) V 0 track pattern recognition for reconstruction of weak decays of hyperons (K 0 s,Λ,....,Ω)

4-6 April 2006 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    0 41 K + 13 K - 42 K 0 ~500 charged primaries in acceptance ( mrad) → high granularity

4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI 6 Open Charm Reconstruction D0→KD0→K Some hadronic decay modes D  (c  = 317  m): D +  K -  +  + (9  0.6%) D 0 (c  =  m): D 0  K -  + (3.9  0.09%)

4-6 April 2006 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

4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI 8 Rates and Doses for Open Charm Assume  D / central collision (for 15 A GeV)  4% branching ratio (for D 0  K -  + )  50% geometrical acceptance  5% reconstruction efficiency  → detected D / central collision Estimate Rates  10 7 collisions/sec  50% duty cycle  → 1000 D/day Estimate Doses  Flux: part/cm 2 /sec at z=5cm Θ=100 mrad  part/cm 2 or 30 Mrad in a 10 week run

4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI 9 1 st Guess on Geometry Acceptance: 50 to 500 mrad Magnet: ~ 1 Tm bending power ~ 1 m field length 1 x 1 m aperture 1 st plane: z=5cm ; size 25 cm 2 covers 100 to 500 mrad last plane: z=100cm; size 1 m 2 assume 7 planes  3 or 2 pixel  4 or 5 strip Pixel Strip z = 5,10,(20) cm z = (20),40,60,80,100 cm mostly guided by open charm needs

4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI 10 Possible Configuration of 1 st +2 nd Plane Inspired by BTeV Detectors can be moved in two halfs Remove sensors from beam during focusing Only two module geometries 1 st plane and inner part of 2 nd plane should be replaceable after a run

4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI 11 Vertex Detector: The MAPS Option I Pros:  done with commercial CMOS process  sensor thickness below 100 μm  pixel pitch μm  resolution 3 μm Under work:  fast column based readout ultimate speed: ~ 5 μs frame time  radiation hardness currently: 1 Mrad CBM related MAPS R&D in 2005:  MIMOSA 11: radiation tolerance  MIMOSA 13: current readout MIMOSA IV IReS / LEPSI Strasbourg Monolithic Active Pixel Sensors

4-6 April 2006 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

4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI 13 1 st 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 15 o

4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI 14 1 st Guess for Strip Tracker II Basic Elements: Inner : 6x4 cm Middle : 6x12 cm Outer :6X20 cm +40 cm -40 cm Read out +4cm - 4cm by V. Saveliev Tracking Station Nr. 6 Open questions:  strip length (reduce fake hits)  location of read-out (all at edge ?)

4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI 15 D 0 Reconstruction I Assume:  100 μm pixel layers  200 μm strip layers D0  K -,  + signalBackground Reconstructed events Z-vertex(cm) Z vertex IP cut cuts optimized for significance Au+Au 25 A GeV

4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI 16 D 0 Reconstruction II Assume:  10 7 interactions/sec  1% momentum resolution effective

4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI 17 Impact of Resolution and Thickness I by I. Vassiliev 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 +

4-6 April 2006 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 D 0 efficiency 5.10 % 1.70 % 0.01 % UrQMD (combinatorial background) Conclusion:  700 μm material budget tolerable  conventional sized (~20000 μm 2 ) hybrid pixel detectors are excluded Note: The dose required for a physics signal increases with decreasing D 0 efficiency.

4-6 April 2006 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

4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI 20 Proposal I Pixel Strip(x,u and y,v) Strip (r,  ) Could be like LHCb-VELO

4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI 21 Proposal II MAPS Strip Hybrids Should deliver unambiguous seeds High resolution tracking with large coverage Ultimate vertex resolution

4-6 April 2006 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  10 7 interactions/sec → tracks/sec Robust tracking needed  confusion in 1 st or 2 nd 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

4-6 April 2006 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....

4-6 April 2006 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

4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI 25 Low Mass Dilepton Spectroscopy II If these are not reconstructed.... those will form a fake open pair tracking efficiency down to 0.1 GeV/c important to suppress background Likely we need  additional coverage  more redundancy  an adapted geometry for dilepton runs

4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI 26  -electrons – Atomic Physics Background by P. Koczon Large cross section for high energetic (> 10 MeV) knock-on electrons. Geant 3 vis PhysRev D V.54/1 p AGeV Au->Au 0.25mm Relative Formula Geant3 In 1 st station:  5 per Au ion passing 1% target  500 per min. bias interaction  compare: ~150 charged hadrons

4-6 April 2006 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 cm 2 ) is exposed to very high doses replacing this part after a major D run is feasible  required dose and also interaction rate depends on D 0 efficiency thin 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

4-6 April 2006 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

4-6 April 2006 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

4-6 April 2006 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

4-6 April 2006 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

4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI 32 CBM R&D working packages Feasibility studies Simulations D  Kπ(π) GSI Darmstadt, Czech Acad. Sci., Rez Techn. Univ. Prague IReS Strasbourg ,ω,   e + e - Univ. Krakow JINR-LHE Dubna GSI Darmstadt J/ψ  e + e - INR Moscow GSI RBI Zagreb π, K, p ID Heidelberg Univ, Warsaw Univ. Kiev Univ. NIPNE Bucharest INR Moscow Framework GSI Tracking KIP Univ. Heidelberg Univ. Mannheim JINR-LHE Dubna JINR-LIT Dubna Design & construction of detectors Silicon Pixel IReS Strasbourg Frankfurt Univ., GSI Darmstadt, Silicon Strip Moscow State Univ MEPHI, Moscow CKBM St. Petersburg KRI St. Petersburg Univ. Obninsk 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 TRD (MWPC) JINR-LHE, Dubna GSI Darmstadt, Univ. Münster NIPNE Bucharest TRD (straw) JINR-LPP, Dubna FZ Rossendorf FZ Jülich Tech. Univ. Warsaw ECAL ITEP Moscow IHEP Protvino RICH IHEP Protvino GSI Darmstadt Pusan Univ. PNPI St. Petersburg 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. Magnet FEE, Trigger, DAQ J/ψ  μ + μ - PNPi St. Petersburg SPU St. Petersburg Λ, Ξ,Ω PNPi St. Petersburg SPU St. Petersburg JINR-LHE Dubna Ring finder JINR-LIT, Dubna beam det. Univ. Mannheim GSI Darmstadt JINR-LHE Dubna GSI δ-electrons GSI Darmstadt

4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI 33 The End Thanks for your attention