Download - Silicon Tracker for CBM
Silicon Tracker for CBM
Walter F.J. Müller, GSI, Darmstadtfor 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
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CBM Setup
Radiation hard Silicon pixel/strip detectors in 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
4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI
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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
Low cross sections→ High interaction rates→ Selective Triggers
Vertex detector
V0 reconstruction
Dalitz and conversion rejection
4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI
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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 (K0
s,Λ,....,Ω)
4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI
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A Typical Au+Au Collision
Central Au+Au collision at 25 AGeV:URQMD + GEANT
160 p 170 n360 - 330 + 360 0 41 K+ 13 K- 42 K0
~500 charged primaries inacceptance (50-500 mrad)→ high granularity
4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI
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Open Charm Reconstruction
GeV3%18.0
mm50 μm;10
MeV14
0
21
021
pX
x
dx
X
x
pdx
D0→K
Some hadronic decay modes
D (c = 317 m):D+ K-++ (9 0.6%)
D0 (c = 124.4 m):D0 K-+ (3.9 0.09%)
4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI
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Meson Production in central Au+AuW. 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
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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
4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI
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1st Guess on Geometry
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
Strip
z = 5,10,(20) cm
z = (20),40,60,80,100 cmmostly guided byopen charm needs
4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI
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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
4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI
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Vertex Detector: The MAPS Option I
Pros: done with commercial CMOS
process sensor thickness below 100 μm pixel pitch 20-35 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 IVIReS / 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
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Vertex Detector: The MAPS Option IIDouble 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
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1st Guess for Strip Tracker I4 Strip tracking stations
Tracking Stations Nr. 4 and 6
Double sided Si-Strip detectors:thickness 100 μmpitch 25 μmStereo angle 15o
4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI
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1st Guess for Strip Tracker II
Basic Elements: Inner : 6x4 cm Middle : 6x12 cmOuter : 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
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D0 Reconstruction I Assume:
100 μm pixel layers 200 μm strip layers
D0 K-,+ signal Background
Reco
nst
ruct
ed e
vents
Z-vertex(cm)
Z vertex
IP c
ut
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
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D0 Reconstruction II Assume:
107 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
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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
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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 efficiency5.10 % 1.70 % 0.01 %
UrQMD (combinatorial background) Conclusion:
700 μm material budget tolerable
conventional sized (~20000 μm2) hybrid pixel detectors are excluded
Note:The dose required for a physics signal increases with decreasing D0 efficiency.
4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI
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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
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Proposal I
Pixel
Strip(x,u and y,v)
Strip (r,)
Could be likeLHCb-VELO
4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI
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Proposal II
MAPS
Strip
Hybrids
Should deliverunambiguous 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
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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
4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI
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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
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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
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Low Mass Dilepton Spectroscopy II
ee 0
ee
If these are notreconstructed ..
.. those will form a fake open pair
tracking efficiencydown to 0.1 GeV/c
important to suppressbackground
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
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-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.134
25 AGeV Au->Au 0.25mm
Relative
Formula
Geant3
In 1st 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
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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 doses
replacing this part after a major D run is feasible required dose and also interaction rate depends on D0 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
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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
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Summary III Strip tracker:
100 to 150 μm double sided sensordetailed 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
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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
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CBM and HADESAll you want to know about CBM:Technical Status Report (400 p)
now available underhttp://www.gsi.de/documents/DOC-2005-Feb-447-1.pdf
4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI
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CBM R&D working packages Feasibility studies Simulations
D Kπ(π)GSI Darmstadt, Czech Acad. Sci., RezTechn. Univ. PragueIReS Strasbourg
,ω, e+e-
Univ. KrakowJINR-LHE Dubna GSI Darmstadt
J/ψ e+e-
INR MoscowGSIRBI Zagreb
π, K, p ID Heidelberg Univ,Warsaw Univ.Kiev Univ. NIPNE BucharestINR Moscow
FrameworkGSI
TrackingKIP Univ. HeidelbergUniv. MannheimJINR-LHE DubnaJINR-LIT Dubna
Design & constructionof detectors
Silicon PixelIReS StrasbourgFrankfurt Univ.,GSI Darmstadt,
Silicon Strip Moscow State UnivMEPHI, MoscowCKBM St. PetersburgKRI St. PetersburgUniv. Obninsk
RPC-TOFLIP Coimbra, Univ. Santiago Univ. Heidelberg,GSI Darmstadt,NIPNE BucharestINR MoscowFZ RossendorfIHEP ProtvinoITEP MoscowRBI ZagrebUniv. MarburgKorea Univ. Seoul
TRD (MWPC)JINR-LHE, DubnaGSI Darmstadt,Univ. MünsterNIPNE Bucharest
TRD (straw)JINR-LPP, DubnaFZ RossendorfFZ JülichTech. Univ. Warsaw
ECAL ITEP Moscow IHEP Protvino
RICH IHEP Protvino GSI Darmstadt Pusan Univ. PNPI St. Petersburg
KIP Univ. HeidelbergUniv. MannheimUni. KaiserslauternGSI DarmstadtJINR-LIT, DubnaUniv. BergenKFKI BudapestSilesia Univ. KatowiceWarsaw Univ.PNPI St. PetersburgNIPNE BucharestMEPHI MoscowWuhan Univ.
Magnet
FEE,Trigger,DAQ
J/ψ μ+μ-
PNPi St. PetersburgSPU St. Petersburg
Λ, Ξ,Ω PNPi St. PetersburgSPU St. PetersburgJINR-LHE Dubna
Ring finder JINR-LIT, Dubna
beam det.Univ. MannheimGSI Darmstadt
JINR-LHE DubnaGSIδ-electrons
GSI Darmstadt
4-6 April 2006 Topical Workshop: Advanced Instrumentation for Future Accelerator Experiments, Bergen, Norway --- Walter F.J. Müller, GSI
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The End
Thanks for your attention