High-resolution, fast and radiation-hard silicon tracking station CBM collaboration meeting March 2005 STS working group

Silicon Tracking Station: Working group "Real" design

What is the best design? Version used in present simulations Not really surprising results from simulations including realsitic detector response Pixel Strip Problems: MAPS Event pile-up Radiation tolerance Hybrids Pixel size Material budget Problems: Ghost tracks To be defined: Configuration But also Granularity Material budget

Challenging tasks of the tracking station (I) Micro vertex reconstruction (main task of the ITS) Secondary vertex reconstruction better 50  m (z-coordinate) Extremely high track density Both high resolution and a respectively low material budget are needed. D0→KD0→K

Challenging tasks of the tracking station (II) Background rejection in low mass dielectron spectroscopy Reconstruction of "incomplete" tracks Needs probably much more redundancy If these are not reconstructed.... those will form a fake open pair

What is the best design? Version discussed in the TSR Vacuum chamber with small (and hence thin) window Outer part of station 3 by strip technology? Pixel Strip

Basic Elements: Inner : 6x2 cm Middle : 6x4 cm Outer :6X12 cm FeatureValue/Quantity Angular coverage50 to 500 mrad Number of super layers 4 Detector modules per plane Detector thickness≤ µ m Sensitive detector area 20x20 cm 2 to 50x50 cm 2 Operational temperature ≤40°C Strip pitch25 µ m Strip configuration Valeri's talk

What is the best design? Option proposed by Valeri Pixel Strip(x,u and y,v) Strip (r,  ) Could be like LHCb-VELO

Possible configuration (B-TeV inspired) Outer section of plane 3 outside the vacuum! Highest granularity not needed there Allows using thin vacuum window Detectors can be moved in two halfs. Remove sensors from beam area during focusing Only two different module geometries Optional for MAPS or Hybrids

Generic designs for simulation Hybrid-like Material budget Resolution MAPS-like Radiation hardness Read-out speed

MAPS material budget a first assessment by Michael Deveaux Stacking of sensors due to inactive read-out area Design VELO (LHCb) inspired 0.29 %

What is the best design? Possible direction for future What is the maximum material budget acceptable? Third technology needs additional manpower! MAPS Strip Hybrids Should deliver unambiguous seeds High resolution tracking With large coverage Ultimate vertex resolution

Assessment for GIGATRACKER NA48: CERN-SPSC (K + →   ) Concept (only small area needs to be covered) High rate: 40 MHz / cm ps time resolution Fluence cm 2 (12 Mrad) 0.13  m envisaged x/X 0 < 0.6%

MAPS R&D Dense program of chip submission in 2005 MIMOSA 9 →factor 2 lower signal than expected MIMOSA 10 → MIMOSTAR1 first prototype for STAR IT MIMOSA 11 →Various sensor geometries for studying aspects of radiation tolerance MIMOSA 12 →Multiple charge storage on-pixel, aspects of capacitor performance MIMOSA 13 →Current readout faster, better noise immunity Transfer of one test station to Frankfurt Support R&D efforts starting with MIMOSA11 Aspects of cryogenic operation

R&D: MIMOSA 13 Topology -Technology : AMS (4 metal layer). - Substrate : low doped Hi resistivity substrate (8-10 Ω.cm). - Chip Area : 5,1mm² - Nb of pads : 44 - Pads spacing : 50µm -Current mode maybe adapted to the high speed and high granularity requirements. -Sensor matrix -Matrix control logic -Preamplifier, multiplexer Talk by Sébastien HEINI (IReS)

Strip R&D Sensor (M. Merkin's talk) First steps towards a thin double-sided sensor Oxygenation seems unavoidable to reach radiation tolerance needed Wafers are being ordered FEE (S. Voronin's talk) Started investigation of technologies for micro interconnection (i.e. 25  m pitch) Provide VA readout for prototype sensors

Design optimization Design Optimization Mainframe AlgorithmsDigitizers Final configuration Tracking groups STS group MAPS HitProducer (Michael) Strip HitProducer (Valeri) Physics benchmarks: ûOpen charm i.e D 0 /run ûLow-mass dielectrons S/B < 1/5 ?

STS working packages

Towards a Design Proposal Vertex tracker (ITS)Main tracker (SIT) MAPSfall backStrip Design optimization Granularity Resolution Configuration GSI, IReSGSI, IKFObninsk Choice of technology Sensor Readout Module/plane design IReSMSU/MEPHI R&DIReS, IKFMSU/MEPHI Infrastructure/ Environment Management