P326 Gigatracker Pixel Detector - PowerPoint PPT Presentation

1 / 27
About This Presentation
Title:

P326 Gigatracker Pixel Detector

Description:

No significant degradation at 0.5%Xo per plane. Radiation Levels in Gigatracker (GTK) ... Pixel size 300 um x 300 um = 40 x 40 pixels = 1600 pixels ... – PowerPoint PPT presentation

Number of Views:58
Avg rating:3.0/5.0
Slides: 28
Provided by: giorgios
Category:

less

Transcript and Presenter's Notes

Title: P326 Gigatracker Pixel Detector


1
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 RD for CLIC

2
P326 Proposal
  • 10-11 branching ratio
  • high intensity K beam
  • high background rejection
  • 5.1012 K decays/year
  • 100 events by 2011

3
P326 Beam
Tracking, momentum, time stamp
  • modified NA48 K12 beam line
  • 3.1012 protons on target (400GeV) gt 60 pions,
    20 protons, 14 electrons, 6 kaons
  • overall particle rate 0.8GHz gt
    Gigatracker
  • beam cross-section 12cm2 at GTK

4
GTK Si Pixels
P. Riedler
5
Required Gigatracker time resolution
  • P(gt1hit in Dt) 1-exp(-Dtrate)

Dt ( 2s) _at_0.8GHZ _at_1GHZ 400
27 33 500 33
39 600 38 45
K ?pp0
Dependence of the signal to background (from K
?pp0 ) as a function of the gigatracker time
resolution
6
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 0.5Xo per plane

7
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

8
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

9
Si Sensors
  • Radiation effects
  • type inversion (higher Vb required)
  • leakage current increase
  • DIvola 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 _at_ 25 C )
  • DI reduction 16x _at_ 0 C
  • periodic replacement of station

10
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
11
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 (D200mm) 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

12
Readout Wafer Thinning
200mm Si wafer thinned to 150 mm
J. Salmi/VTT BOND03 CERN
13
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

14
Configuration I
Pads for power supplies and clock (additional
material budget)
15
Configuration II
Max rate on one chip, but chip smaller
16
Configuration IV
60 mm
6 mm
12 mm
24 mm
17
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 lt2)

18
Chip size/data rate
  • With a beam of 24 x 60 mm -gt 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
  • gt 40 x 40 pixels 1600 pixels
  • Avg Rate of center column 96 MHz/cm2
  • gt 86 kHz/pixel
  • gt 138 MHz/chip
  • gt 138 MHz/chip 32 bit 4.4 Gbit/s

19
Cooling
  • Power dissipation (pixel plane) 20W
  • Operating temperature lt 5 C (gt 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 ?

20
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 _at_ T300K)
  • Density (g/cm3 ) 1.9/2.2
  • X0 (g/cm2) 42 ( 21 cm)
  • ( 9.36cm for Si)
  • 2-ply radiator thickness 120 mm

21
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

22
Results with ideal contact between materials
Case A B1 B2 B3 B4
23
Temperature gradient of the Silicon Pixel
detector in dependence of the thermal
conductivity of the cooling plane
24
Results with thermal resistance between materials
25
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.

26
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)
  • gt 2 FELL/DOCT student required (1 already
    available)
  • Mechanics cooling CERN), Ferrara

27
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
Write a Comment
User Comments (0)
About PowerShow.com