SVT

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SVT

• Michael Merkin
• SINP MSU

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Tracking Specifications Summary
Fwd. Tracker Central Tracker
Angular coverage 5o 40o (50 f-coverage at 5o) 35o 125o (gt 90 f-coverage)
Momentum resolution dp/p lt 1 dp/p lt 5
q Resolution 1 mrad 5 10 mrad
f Resolution 1 mrad/sinq 5 mrad/sinq
Luminosity 1035 cm-2 s-1 1035 cm-2 s-1
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Performance Expectations of the Detector

• SVT Barrel Forward
• Barrel Silicon Tracker (BST) Stand Alone Tracker
• f-coverage 2p
• ?-coverage 35o, 125o
• Momentum resolution 50 MeV/c
• f-resolution 5 mrad
• ?-resolution 20 mrad
• Tracking Efficiency gt90

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Performance Expectations of the Detector

• Forward Silicon Tracker (FST) Works with Drift
  Chambers
• f-coverage 2p
• ?-coverage 5o, 35o
• Tracking Efficiency gt90
• Improve Vertex Resolution
• Improve f-resolution

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Design Optimization
Four Barrel Regions 8, 12, 18, 24 modules Three
Forward Regions 15, 15, 15 modules

• maximizes momentum resolution
• Radii of region 1 and region 4
• minimizes multiple scattering
• no overlap of modules
• all electronics outside active area
• strip layout reduces number of masks needed
• strip layout with variable angles reduces dead
  areas
• use of previously designed readout chips
  (FSSR2)

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SVT BST
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SVT FST
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Background Studies
Full Luminosity FST Rates Summary
EM      Hadronic    Total
EM      Hadronic    Total
1a 1080 3.78 1083 1b 954
3.55 958 2a 895 3.40
899 2b 872 3.47 876 3a
851 3.33 854 3b 894
3.42 897
1a 31.3 2.45 33.7 1b 29.2
2.23 31.5 2a 31.1 2.15
33.3 2b 26.3 2.22 28.6 3a
24.6 2.16 26.8 3b 24.2
2.23 26.4
No Energy Cut
E Dep gt 20 KeV
All rates in MHz
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Background Studies
Full Luminosity Radial FST Rates
19.35 MHz
23.87 MHz
28.56 MHz
33.70 MHz
y 19.029 mm
Layer 1a
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Background Studies
Full Luminosity Radial FST Rates
Rate (MHz)
mm
Transverse distance from beamline
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Background Dose, Fluence Studies
BST
Layer GeV/s GeV/(s cm2) mrads/s
mrads/(s cm2) rad/year rad/(year cm2)
1a 7147.8 19.05
4.39 0.011708 138480
369.24 1b 3889.4 10.37
2.38 0.006371
75352 200.92 2a 4578.2
4.06 0.93 0.000833
29566 26.27 2b
3551.7 3.15 0.72
0.000646 22936
20.38 3a 3828.5 1.51
0.34 0.000137 10988
4.34 3b 3295.7
1.30 0.29 0.000118
9459 3.73 4a
3145.5 0.93 0.21
6.360e-05 6771
2.00 4b 2743.3 0.81
0.18 5.547e-05 5905
1.74
1 year 31,536,000 s
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Background Dose, Fluence Studies
BST No Field
Layer TeV/s TeV/(s cm2) mrads/s
mrads/(s cm2) krad/year krad/(year cm2)
1a 9375.3 24.998 5759.6
15.357 181630
484.31 1b 3013.5 8.035
1851.3 4.936 58381
155.67 2a 2793.4
2.482 572.0 0.508
18039 16.03 2b
1336.4 1.187 273.6
0.243 8630
7.66 3a 1566.2 0.618
142.5 0.056 4495
1.77 3b 875.9
0.346 79.7 0.031
2514 0.99 4a
1021.0 0.302 69.6
0.020 2197
0.65 4b 593.9 0.179
40.5 0.012 278
0.37
1 year 31,536,000 s
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Background Dose, Fluence Studies
FST
Layer GeV/s GeV/(s cm2) mrads/s
mrads/(s cm2) rad/year rad/(year
cm2) 1a 3933 3.56
0.85 0.77
27042 24.5 1b 3370
3.05 0.73
0.66 23166 21.0
2a 3288 2.98
0.71 0.65 22609
20.5 2b 3102
2.81 0.67 0.61
21325 19.3 3a
3123 2.83 0.68
0.61 21463
19.6 3b 3094 2.81
0.68 0.61
21269 19.3
1 year 31,536,000 s
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Background Dose, Fluence Studies
FST No Field
Layer TeV/s GeV/(s cm2) mrads/s
mrads/(s cm2) kilorad/year rad/(year
cm2) 1a 52.92 48.00
11.53 10.46
363.8 329.9 1b
43.45 39.41 9.47
8.59 298.7
270.9 2a 39.82 36.12
8.68 7.87
273.7 248.3 2b
35.18 31.91 7.66
6.95 241.8
219.3 3a 32.88 29.83
7.16 6.50
226.0 205.0 3b
28.06 25.45 6.11
5.54 192.9
175.0
1 year 31,536,000 s
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SVT Cooling (FSSR2 ASIC)
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Summary of Sensor Specifications

• Single Sided Construction
• Lower cost higher production yields with less
  defects

• High resistivity (5k?/cm) n-type bulk
• Sensor can be fully depleted at relatively low
  voltage

• lt100gt Surface Orientation
• Reduces sensor surface damage due to radiation

• Al strips AC coupled to p strip implant strips
• Protect readout ASIC from DC strip currents

• Surface Passivation
• To protect the semiconductor surface from
  electrical and chemical contaminants

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Summary of Sensor Specifications

• Overhang of AL strips (6 µm) over p implants
• Improves HV stability of the sensor

• Bias Voltage to strips via Polysilicon Resistors
• Decouples individual biased AL strips, best
  radiation performance

• Guard Ring
• Shapes the electric field at the border of the
  active area

• Outer n Protecting Ring
• Defines the volume, prevents high field at the
  sensors edge

• Low Leakage Current
• Reduces noise

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BST Sensor Cross Section
Hartmann, Frank. Evolution of Silicon Sensor
Technology in Particle Physics. Springer Berlin /
Heidelberg, 2009.
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Sensor Specifications
Mechanical Layout Summary Outer
Size 42.000 x 111.625 mm Active Area 40.032 x
109.955 mm Dicing Tolerance 20µm of readout
strips 256 of intermediate strips 256 Implant
strip pitch 78 µm Readout strip pitch 156
µm Implant strip width 20 µm Aluminum strip
width 26 µm Implant width / pitch ratio
.256 Angle of strips 0(strip 1) to 3(strip
256)
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Sensor Specifications
Summary of Electrical Properties Full depletion
voltage 40ltVlt100 (25C_at_lt45RH) Interstrip
capacitance lt1.2 pf/cm Leakage current (_at_
depletion V) lt1nA/cm2 Strip to back side
capacitance lt0.2 pF/cm Interstrip isolation
(_at_150V) gt1 G? Resistance of Al strips lt 20
ohm/cm Coupling capacitance gt10 pf/cm Total
(strip) capacitance (Ctot Cint Cback
at 1 MHz) 1.3 pf/cm Value of poly-silicon bias
resistor 1.5 M? Single strip DC current lt
3 nA
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BST Hybrid Sensor Layout
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BST Module Sensor Layout
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Thanks!
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Backup
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Sensor Testing
Tests by vendor for each sensor

• Sensor Leakage Current

• Interstrip, backplane, and total capacitance

• Depletion voltage

• Interstrip resistance, Poly bias resistors,
  Al Strip resistance

Information to be supplied by the vendor for each
sensor

• ID engraved in the area provided on the
  sensor

• For each wafer, list the sensor ID numbers

• Test results for each sensor

• Traceability data of processing (batch
  relative yield, start and end date, and wafer
  numbers

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FSSR2 - Specifications

• High density 128 channels / chip
• Low Power 3 mW / channel
• Data driven architecture no trigger
  (synchronized with DAq with timestamp clock)
• Zero suppressed data readout
• Fast output 840 Mbit/sec readout capability
  (1-6 programmable serial outputs)
• IP License from INFN to procure additional chips

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FSSR2 - Validation

• Current Test Plan consists of 95 tests exercising
  all aspects of the ASIC to verify specifications
• Test Board created to inject external charge and
  connect chip to sensor
• Document results to aid in collaboration with
  other facilities
• Tests with 1st article SVT modules scheduled for
  2010
• CLAS-Notes
• 2008-021, 2008-022, 2008-024, 2008-028, 2009-008,
  2009-015, 2009-021

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Radiation Length of Module Components
Material Radiation Length X0 mm Thickness mm Thickness X0
Silicon 93.700 0.300 0.320
Epoxy 443.700 0.025 0.007
GFRP 250.000 0.250 0.100
Rohacell 71 450.000 2.000 0.040
GFRP 250.000 0.250 0.100
Epoxy 443.700 0.025 0.007
Silicon 93.700 0.300 0.320
Total   3.150 0.894
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ASIC Survey

• Options SVX4, FSSR2

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Comparison of ASICs
Parameter FSSR2 SVX4
Designed for BTeV CDF/D0
Engineering run Yes Yes
Used in experiment No CDF/D0
Channel/chip 128 128
Data architecture self trigger and time stamp pipeline/needs external trigger
Readout rate 105 MByte/s, 1- 6 programmable serial outputs 56 MBytes/s
ADC type 3 bit flash 8 bit Wilkinson
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FSSR2 tests
Signal 20000e-
Worst case S/Ngt10
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Signal rate distributions for the laser and
injected signal
Signal 20000e-
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Sensor overview
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2 Dummy Strips
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Guard rings and Bias Line
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Scratch Pads
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Corner Pad
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Corner pad and Scratch Pads
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PolySilicon Resistors
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