P326 Gigatracker Pixel Detector Requirements material budget, time resolution, radiation hardness,... Hybrid pixels: sensor, readout chip, bump bonding Electronics system (Mechanics and) Cooling Resources - Workplan Possible interest in R&D for CLIC 04/10/06 G. Stefanini/LC WG/P326/GTK

G. Stefanini/LC WG/P326/GTK P326 Proposal 10-11 branching ratio high intensity K beam high background rejection ≈ 5.1012 K decays/year ≈ 100 events by 2011 04/10/06 G. Stefanini/LC WG/P326/GTK

G. Stefanini/LC WG/P326/GTK P326 Beam Tracking, momentum, time stamp modified NA48 K12 beam line 3.1012 protons on target (400GeV) ==> 60% pions, 20% protons, 14% electrons, 6% kaons overall particle rate ≈ 0.8GHz ==> “Gigatracker” beam cross-section ≈ 12cm2 at GTK 04/10/06 G. Stefanini/LC WG/P326/GTK

G. Stefanini/LC WG/P326/GTK GTK Si Pixels P. Riedler 04/10/06 G. Stefanini/LC WG/P326/GTK

Required Gigatracker time resolution P(>1hit in Dt) =1-exp(-Dt*rate) Dt ( ±2s) @0.8GHZ @1GHZ 400 27% 33% 500 33% 39% 600 38% 45% K+ p+p0 Dependence of the signal to background (from K+ p+p0 ) as a function of the gigatracker time resolution 04/10/06

Material Budget Requirements Full GEANT simulation Impact of GTK material budget beam momentum resolution angular beam resolution vertex resolution missing mass No significant degradation at ≈ 0.5%Xo per plane 04/10/06 G. Stefanini/LC WG/P326/GTK

Radiation Levels in Gigatracker (GTK) Calculated fluence ≈ 2. 1014 (1 MeV neq cm-2) 100 days For comparison: ATLAS SCT/CMS TK ≈ 1.5 1014 (1 MeV neq cm-2) 10 years Safety factors in estimates 04/10/06 G. Stefanini/LC WG/P326/GTK

GTK Hybrid Pixel Design Parameters (Preliminary) hybrid pixels Pixel cell size 300mm x 300mm Sensor thickness 200mm charge collection time vs signal amplitude Pixel chip thickness ≤ 100mm Bump bonding Pb-Sn Material budget ≈ 0.4% X0 (each station) Operating temp. T ≤ 5 °C (in vacuum) Cooling ≈ 120mm CF radiator/support with peripheral cooling 04/10/06 G. Stefanini/LC WG/P326/GTK

G. Stefanini/LC WG/P326/GTK Si Sensors Radiation effects type inversion (higher Vb required) leakage current increase DIvol=a fne (a ≈ 5 x 10-17 A/cm) Remedies M-CZ material (to be studied) operation at low(er) temp (in vacuum...) I  exp(-Eg/2kT) (up to ≈ 200mA/cm2 @ 25 °C ) DI reduction ≈ 16x @ 0 °C periodic replacement of station 04/10/06 G. Stefanini/LC WG/P326/GTK

G. Stefanini/LC WG/P326/GTK GTK Pixel ASIC Technology: CMOS8 (0.13mm) speed, density, power, (radiation hardness) availability/obsolescence, MPW access cost (prototyping, engineering run) frame contract at CERN for applications within the HEP community Conceptual study well advanced definition of system architecture noise (mixed-signal application) upcoming MPW submission of functional blocks (amplifier, discriminator, TDC, ...) ALICE pixel ASIC (CMOS6 0.25mm) 8,192 pixel cells 04/10/06 G. Stefanini/LC WG/P326/GTK

G. Stefanini/LC WG/P326/GTK Bump Bonding Bump bonding of 150mm pixel chips to 200mm sensors: in volume production (ALICE SPD 107 pixels) Pb-Sn (VTT/Finland) Thinning of pixel wafers (D=200mm) is done after bump deposition Thinning/bb to 100mm (or less) requires prototyping Preliminary test under way with ALICE pixel dummy wafers Key issue: flatness of sensors ©VTT Pb-Sn ~20-25µm 04/10/06 G. Stefanini/LC WG/P326/GTK

Readout Wafer Thinning 200mm Si wafer thinned to 150 mm J. Salmi/VTT BOND’03 CERN 04/10/06 G. Stefanini/LC WG/P326/GTK

Chip Size - Power Management Power dissipation up to 2W/cm2 (preliminary estimate) Material budget constraints on coverage of beam area Lowest material budget with only pixel matrix in beam I/O pads and cooling at periphery This leads to power management problems Beam cross section adjusted (≈ rectangular) to ease matching of optimized chip layout without degradation of beam quality 04/10/06 G. Stefanini/LC WG/P326/GTK

Configuration I Highest rate Pads for power supplies and clock (additional material budget) 04/10/064 July, 2006 A. Kluge

Configuration II Max rate on one chip, but chip smaller 04/10/064 July, 2006 A. Kluge

Configuration IV 60 mm 6 mm 12 mm 24 mm 04/10/064 July, 2006 A. Kluge

G. Stefanini/LC WG/P326/GTK Time Stamp Fast discriminator with time walk compensation is key element TDC bin size 100ps TDC options one TDC per pixel cell (linear discharge) cell area, power dissipation, dead time group multiplexed TDC efficiency loss (must be limited to <2%) 04/10/06 G. Stefanini/LC WG/P326/GTK

Chip size/data rate With a beam of 24 x 60 mm -> 2 x 5 chips Assume chip matrix of 40 rows x 40 columns: 12 mm x 12 mm = 144 mm2 Pixel size 300 um x 300 um => 40 x 40 pixels = 1600 pixels Avg Rate of center column: ~ 96 MHz/cm2 => 86 kHz/pixel => 138 MHz/chip => 138 MHz/chip * ~ 32 bit = ~4.4 Gbit/s 04/10/064 July, 2006 A. Kluge

G. Stefanini/LC WG/P326/GTK Cooling Power dissipation (pixel plane) ≈ 20W Operating temperature < 5 °C (==> sensor leakage current) CF radiator fins coupled to cooling circuit Adhesive/filler (≈ 50mm) thermal conductivity ≈ 1 W/(m K) Cooling system options fluid coolant evaporative cooling C4F10 C4F8 Peltier cell ? 04/10/06 G. Stefanini/LC WG/P326/GTK

Carbon Fibre (CF) Composites CTE (ppm/K) ≈ -1.5/+12 Th. conductivity (W/m K) ≈ 150 (M55J) ≈ 1,000 (K-1,100) ≈ 390 (Cu) ≈ 145 (Si @ T=300K) Density (g/cm3 ) ≈ 1.9/2.2 X0 (g/cm2) ≈ 42 (≈ 21 cm) (≈ 9.36cm for Si) 2-ply radiator thickness ≈ 120 mm 04/10/06 G. Stefanini/LC WG/P326/GTK

Initial Situation Case A: without cooling plane Case B: with cooling plane and with different thermal contact resistances between the solids Total Heat Load of 2 W/cm² Case Cooling plane Thermal conductivity k [W/(cm K)] B1 Toray M55J 1.5 B2 Carbon-Carbon 2.5 B3 Thornel 8000X panels 8.0 B4 Thornel K-1100 10.0 04/10/06

Results with ideal contact between materials Case A B1 B2 B3 B4 04/10/06

Temperature gradient of the Silicon Pixel detector in dependence of the thermal conductivity of the cooling plane 04/10/06

Results with thermal resistance between materials 04/10/06

Influence of the thermal resistance It is quite difficult to calculate the real thermal resistance of the contact surfaces between the materials. Differences between hand calculation and CFD-Simulation, show the influence of the bumps. Case A B1 B2 B3 B4 ΔT, hand calculation 72.0 54.0 46.3 25.9 22.3 ΔT, CFD-Simulation 80.0 59.6 49.5 26.6 23.7 ΔT with thermal contact resistance Rt,c= 0.2 x 10-4 m2K/W -- 33.9 28.4 Rt,c= 0.9 x 10-4 m2K/W 37.5 31.6 04/10/06

Detector Development Team (Very preliminary) Sensors CERN 1 Phys Staff, 1 Fellow INFN Ferrara 1 PostDoc (tbc) Analog electronics CERN 1 Eng, 1 Fellow (but...) INFN Torino 2 Eng Electronic system & integration CERN 1 Eng INFN Ferrara (tbd) INFN Torino (tbd) CERN staff (sensors and system) for the time being fully committed to LHC activities (ALICE SPD) ==> 2 FELL/DOCT student required (1 already available) Mechanics & cooling CERN), Ferrara 04/10/06 G. Stefanini/LC WG/P326/GTK

Planning (Preliminary) System architecture def. & simulation H1 YR1 Small scale prototype submission ≈ Q3 YR1 Engineering run 1 submission ≈ Q2 YR2 Engineering run 2 submission ≈ Q2 YR3 Production of final chip ≈ Q1 YR4 Detector assembly ≈ Q3 YR4 YR1 start of PH support & funding 04/10/06 G. Stefanini/LC WG/P326/GTK