The DØ Silicon Microstrip Tracker
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Transcript of The DØ Silicon Microstrip Tracker
The DØ Silicon Microstrip TrackerThe DØ Silicon Microstrip Tracker
Frank FilthautUniversity of Nijmegen / NIKHEF
NIKHEF, 4 August 2000
DD
4 August 2000NIKHEF
DDTevatron Run II UpgradeTevatron Run II Upgrade
Modification of Tevatron parameters:
Start of Run II: 1 March 2001
Aim: collect 2 fb-1 in two years (might be more…)
Switch from 396 ns to 132 ns bunch spacing at luminosity 1032 cm-2 s-1
Keep zero crossing angle for 396 ns operation; aim for 136 rad angle for 132 ns operationBeam spot: 35 m transverse, 25 cm longitudinal (10 cm for nonzero crossing angle)
Run 1
Run 2 (initial)
Run 2 (eventual)
Bunch spacing (ns)
3500 396 132
Luminosity (1031 cm-2 s-
1)
0.16 8.6 21
Interactions/crossing
2.5 2.3 1.9
4 August 2000NIKHEF
DDDØ Run II UpgradeDØ Run II Upgrade
Addition of central axial 2T magnetic field (SC solenoid in front of calorimeter cryostat)
Replacement of tracking system by combination of scintillating fibers (Central Fiber Tracker) and silicon sensors (Silicon Microstrip Tracker)
Central (CPS) and forward (FPS) preshower detectors
Extend muon chamber coverage to larger , smaller granularity
Upgraded calorimeter, trigger, DAQ electronics
Physics aims:
B-tagging based on b lifetime Improved electron and muon identification and
triggering Improved tau identification Charge sign determination
High pt central physics (tt, EW, Higgs and other searches): high multiplicity
Low pt physics (bb, QCD): requires good
forward coverage (e.g. lepton ID for || < 3)
4 August 2000NIKHEF
DDDØ Run II UpgradeDØ Run II Upgrade
4 August 2000NIKHEF
DDDØ Run II UpgradeDØ Run II Upgrade - Tracking - Tracking
ForwardPreshower
Silicon Microstrip Tracker Fiber Tracker
Solenoid Central Preshower
All share the same SVX IIe front-end electronics
4 August 2000NIKHEF
DD
1 2 3 4 5 6
1 2 3 4
5 67 8
9101112
SMT DesignSMT Design
Basic SMT Design:
Barrels F-Disks H-DisksLayers/planes 4 12 4
ReadoutLength
12.4 cm 7.5 cm 14.6 cm
Inner Radius 2.7 cm 2.6 cm 9.5 cmOuter Radius 9.4 cm 10.5 cm 26 cm
6 barrels 12 F disks 4 H disks
Axial strips to be used in 2nd level Silicon Track Trigger (STT) stringent requirements on alignment
Totals: 793k channels
3.0 m2 (of which 1.6 m2 DS)
4 August 2000NIKHEF
DDSMT DesignSMT Design
Layers 1 (3): 12 (24) DS, DM 900 ladders produced from 6” wafers (barrels 1 & 6: SS axial ladders from 4” wafers)
Layers 2 (4): 12 (24) DS 20 ladders produced from 4” wafers
SMT barrel cross-section:
Ladder count: 72 SS + 144 DS (900) + 216 DS (20)
4 August 2000NIKHEF
DDAnatomy of a LadderAnatomy of a Ladder
Ladders supported by “active” (cooled) and “passive” bulkheads
Ladders fixed by engaging precision notches in beryllium substrates on posts on bulkheads
Beryllium cools electronics expect chips to operate at 25 0C using
80% H2O/20% ethyl glycol mixture at –10 0C silicon should be at 5-10 0C
High Density Interconnect (HDI) tail routed out between outer layers
Carbon-fibre/Rohacell rails glued to sensors for structural stiffness
4 August 2000NIKHEF
DDSiliconSilicon
Significant fraction of silicon will undergo type inversion
Prefer high initial Vdepl for silicon at low radii
Specification of Vdepl, Vbreak
Selection of sensors at hand
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Calculated radiation dose as a function of radius (z=0):
Quality control at vendors & DØ institutes:
Ileak < 10 A at Vbias = Vdepl + 10V
20V < Vdepl < 60V
Polysilicon bias resistors: 1 M < Rbias < 10 M (DC bias pad)
Rinter-strip G Coupling capacitors: 10-15 pF/cm f(shorted cap’s) < 2% at min(Vdepl+15V,
90V)
4 August 2000NIKHEF
DDSensorsSensors
Need 144 sensors (2/detector)
Pitch: 50 m Typical Vdepl: 30 V All sensors delivered
by Micron Flatness problems
( 60 m) a concern
Single-sided
4 August 2000NIKHEF
DDSensorsSensors
Need 432 sensors (2/detector) Pitch: p-side 50 m, n-side 62.5 m Typical Vdepl: 20-40 V Slow sensor delivery by Micron
accepting sensors with higher Rbias
Double-sided 20
p-side n-side
4 August 2000NIKHEF
DDSensorsSensors
Need 144 sensors Pitch: p-side 50 m, 900 n-side 153 m Produced from single sensor (6” technology) Using DM layer, gang 2 n-side strips together to
form 1 readout channel Typical Vdepl: 50 V
Double-sided, double-metal
4 August 2000NIKHEF
DDSensorsSensors
Sensor delivery from Micron has been slow (30% yield) mainly due to p-stop defects on mask (noise affecting 10-15 strips) 5 sensors / week schedule problem, accepting few sensors with 1 p-stop defect
Double-sided, double-metal
4 August 2000NIKHEF
DDSensorsSensors
Need 144 sensors (12 detectors/disk) Pitch: n-side 62.5 m, p-side 50 m
(flexible pitch adaptor on n-side) Stereo angles: 150
Sensor delivery: Micron: delivered 125 sensors with reasonable
characteristics: Vdepl 60-70 V Eurisys: delivered 65 sensors:
First two batches: Vdepl 15-20 V, Vbreak 70-80 V Last batch ( 25 sensors) with better implants:
Vdepl 30-40 V, Vbreak 80-100 V
F-wedge
4 August 2000NIKHEF
DDSensorsSensors
Need 384 sensors (2/detector, 48 detectors/disk) Single-sided, glued back-to-back Pitch: 80 m Stereo angles: 7.50
Typical Vdepl: 60 V All sensors delivered by ELMA
H-wedge
4 August 2000NIKHEF
DDSVX IIe ChipSVX IIe Chip
SVX chip originally designed by LBL - FNAL for readout of CDF vertex detector, optimised for capacitances of 10-35 pF, ENC = 350e- + 50e-/pF
128-channel 8-bit digital chip, 1.2 m rad-hard technology
Both signal polarities Rise time set to integrate 99% of signal in 100 ns
(for 132 ns operation) Double correlated sampling for dynamic “pedestal”
subtraction Front end capacitor discharged during “beam gaps” Pipeline depth 32 max. 106 MHz readout speed (both edges of 53 MHz clock)
4 August 2000NIKHEF
DDSVX IIe ChipSVX IIe Chip
Daisy-chained readout of max. 9 chips Online sparsification using common threshold.
Modes: All channels Only above threshold Include 1 or 2 neighbours on either side (even if on
adjacent chips) Adjustable ramp rate (dynamic range) Power dissipation 5 mW/channel Unlike SVX III now in use by CDF, not deadtime-less
4 August 2000NIKHEF
DDHigh Density InterconnectHigh Density Interconnect
Two-layer flex-circuit mounted directly on silicon, housing SVX chips as well as passive electronics
Kapton based, trace pitch 200 m Connects to “low-mass” cable using Hirose
connector 9 different types for the 5 sensor types
2 for each sensor type except H disks 2 types for each ladder differ only in tail length
Laminated to beryllium substrate (total mass 0.041 X0, of which 0.014 X0 from Si)
Need 912 HDI’s
9-chip HDI H-wedge HDI
4 August 2000NIKHEF
DDProduction SequenceProduction Sequence
Probe Test Silicon Sensor
at Micron
Silicon Sensors
Test Bare HDI
Laminate HDI
Mount components on
HDI
Test stuffed HDI
Burn-in HDI
HDI
Build Ladder/Wedge Mount HDI on Silicon
Wirebond Detector
Burn-in Ladder
Laser Test
Build Full Wedge (H) Mount on Support
structure
Read out Detector
Probe Test Silicon Sensor
in house
“fail”
“fail”
Outside Co.
University
Fermilab
Micron
Eurisys
ELMA
Promex
Silitronics
Dyconex
4 August 2000NIKHEF
DDLadder Production in steps (9-chip)Ladder Production in steps (9-chip)
1. Apply pattern of non-conductive epoxy on p-side beryllium
2. Align beryllium with respect to active sensor, apply pressure and cure for 24 hr
3. Align active & passive sensors w.r.t. each other, apply wirebonds.
Then use separate fixture to position carbon-fibre rails. Use conductive epoxy to ground “passive” beryllium. Cure for 24 hr
4 August 2000NIKHEF
DDLadder Production in steps (9-chip)Ladder Production in steps (9-chip)
4. Use “flip fixture” to have n-side on top
5. Apply epoxy to n-side beryllium, fold over and secure HDI. Apply pressure and cure for 24 hr.
Then apply n-side Si-Si and Si-SVX wirebonds
6. Encapsulate bonds at HDI edges.
Connect “active” beryllium to cable ground
4 August 2000NIKHEF
DDTesting & RepairsTesting & Repairs
Bonds need to be plucked
- 50
0
50
100
150
200
250
0 128 256 384 512 640 768 896 1024 1152
mean
noise x10
diff . noise x- 1
Bad ground connection
Broken capacitors: cause SVX front-end to saturate, tends to affect neighbouring channels as well pluck corresponding bonds
Bad grounding of beryllium substrates causes large pedestal structures as well as high noise ensure RBe-gnd < 10
Repair broken / wrong bonds Replace chips / repair tails damaged during
processing
4 August 2000NIKHEF
DDBurn-in & Laser TestsBurn-in & Laser Tests
0
64
128
192
256
0 128 256 384
pulse height
Dead Channel
Laser
Laser Test: Energy just < Si bandgap
(atten. length 400 m test whole sensor)
Find dead & noisy channels
Determine initial operating voltages (from pulse height plateau, Ileak-V curve)
Burn-in Test:
Long-term (72 hr, 30’ between runs) test of whole ladder/wedge (conditions close to those in experiment)
x-y movable laser head
4 August 2000NIKHEF
DDOverall Quality (first half-cylinder)Overall Quality (first half-cylinder)
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Detector classification:
Dead channel: laser response < 40 ADC counts
Noisy channel: pedestal width > 6 ADC counts (normally < 2 counts excluding coherent noise)
Grade A: less than 2.6% dead/noisy channels
Grade B: less than 5.2% dead/noisy channels
Use only detector grades A,B; mechanically OK
Example for 9-chip detectors:
Dead Noisy
(better for other detector types)
4 August 2000NIKHEF
DDProduction Status and ProjectionProduction Status and Projection
Projected rates: assumed yield capacity
9-chip: 9.0/week 80% 15/wk 6-chip: 5.4/week 85% 10/wk H-wedge: 6.2 week 85% 10/wk F-wedge: 4.3/week 90% 15/wk
Yield Folded Detector Production
0
0.2
0.4
0.6
0.8
1
31-Mar-99 9-Jul-99 17-Oct-99 25-Jan-00 4-May-00 12-Aug-00 20-Nov-00
Date
Fra
cti
on
Co
mp
lete
9 Chip
3 chip
6 Chip
H disk
F Disk Nov 1, 00
Aug 10, 00
July 7
50% line
Rates include production, but in general dominated by sensor delivery.
However, HDI “stuffing” at Promex (9-chip) also a concern (wire bond pull strength, HDI bubbling during surface mount)
(as of July 7)
4 August 2000NIKHEF
DDBarrel Assembly in stepsBarrel Assembly in steps
1. Insert individual ladders into rotating fixture using 3D movable table
2. Manually push notches against posts (all under CMM)
Rule of thumb: Align to 20 m (trigger) Survey to 5 m (offline)
Precisely machined bulkheads Barrel assembly done inside out (protect wire
bonds)
4 August 2000NIKHEF
DDBarrel AssemblyBarrel Assembly
Layer 4 glued to bulkheads (providing structural stiffness, holding passive BH)
Thermally conductive grease applied (active BH only) for other layers
First 3 barrels assembled ( 4 weeks/barrel, excluding survey)
3. Secure ladder using tapered pins
4 August 2000NIKHEF
DDBarrel AlignmentBarrel Alignment
Shift d across ladder (3 m) Shift in radius (from ladder
flatness, better than 60 m) Rotation in ladder plane
(10 m 3 m) Rotation about short ladder
axis (70 m 4.6 m) Rotation about long ladder
axis (80 m 3.2 m)
Results for first barrel (similar for other two):
Should be OK for trigger purposes
Example: distribution for :
Note: relevant quantities are distributions’ RMS values (trigger accounts for average offsets)
4 August 2000NIKHEF
DDF-Disk AssemblyF-Disk Assembly
F-disk assembly less critical (not included in trigger), nevertheless performed under CMM
Quick process After assembly, “central” F-disk cooling rings
screwed onto active barrel bulkheads
z=0
Vdepl H H H HHHL ML L LM
Distribution of different quality devices over disks:
H/M = Micron high/medium Vdepl, L = Eurisys low Vdepl
4 August 2000NIKHEF
DDSupport CylinderSupport Cylinder
Double-walled carbon fibre structure supporting all but H disks (supported by CFT layer 3)
Split support (cut at z=0) introduced very late: gain 6 months of “schedule time” (installation can be done with end-cap calorimeter cryostats on platform)
First half-cylinder ready
4 August 2000NIKHEF
DDReadout ElectronicsReadout Electronics
For 5% occupancy, 1 kHz trigger rate: 1010 bits/s need error rate 10-15
Exercise readout system as much as possible before installation in experiment 10% system test using full readout chain (readout full F disk, barrel, barrel-disk assembly, H disk)
Complete readout chain (including L3 analysis, data storage) tested on several detectors
Monitoring Control
platformplatform
SEQ
SEQ
SEQ
SEQ
SEQ
SEQ
VRB Controller
Optical Link1Gb/s
VBD
V R B68k
Secondary Datapath
VME
3M
1553
NRZ/ CLK
IB
L3 HOST
ExamineExamine
HDI
Low Mass
4 August 2000NIKHEF
DD
Milestone Finish Date Completed
Barrel 1 Complete April 18, 2000 May 18, 2000Barrel 2 Complete May 23, 2000 June 13, 2000Barrel 3 Complete June 28, 2000 July 14, 2000Barrel 4 Complete July 27, 2000Barrel 5 Complete August 24, 2000Barrel 6 Complete September 22, 2000
F Disk 0 Complete March 28, 2000 March 31, 2000F Disk 1 Complete April 11, 2000 May 10, 2000F Disk 2 Complete April 25, 2000 May 23, 2000F Disk 3 Complete May 9, 2000 June 15, 2000F Disk 4 Complete May 23, 2000 June 30, 2000F Disk 5 Complete June 21, 2000 July 10, 2000F Disk 6 Complete July 6, 2000 July 19, 2000
F Disk 7 Complete July 20, 2000F Disk 8 Complete August 3, 2000F Disk 9 Complete August 17, 2000F Disk 10 Complete August 31, 2000F Disk 11 Complete September 15, 2000F Disk 12 Complete October 6, 2000
H Disk 1 Complete May 17, 2000H Disk 2 Complete July 7, 2000H Disk 3 Complete August 25, 2000H Disk 4 Complete October 16, 2000
South Half-Cylinder Complete and Ready to Move to DABJuly 27, 2000North Half-Cylinder Complete and Ready to Move to DABOctober 27, 2000
In preparation
Done
DoneDoneDone
Done
DoneDone
Started
Done
DoneDone
Started Half done
ScheduleSchedule
4 August 2000NIKHEF
DDCOSTWBS DESCRIPTION EST
1.1.1 SILICON TRACKER 7,857,0731.1.1.1 Engineering & Design 525,5411.1.1.1.1 SVX II engineering 157,5001.1.1.1.2 MOSIS submission 55,0001.1.1.1.3 UTMC submission 113,6001.1.1.1.4 HDI engineering 01.1.1.1.5 Test readout system 199,4411.1.1.2 Disks 1,407,5071.1.1.2.1 F disk 859,4851.1.1.2.1.1 F wedge detectors 539,3651.1.1.2.1.2 F wedge berylium 24,5801.1.1.2.1.3 Probe testing 51,9041.1.1.2.1.4 F disk fixtures 25,6951.1.1.2.1.5 F wedge fabrication 23,6041.1.1.2.1.6 F Disk Support 128,2921.1.1.2.1.7 F wedge det. spares 66,0451.1.1.2.2 H disk 460,9861.1.1.2.2.1 H wedge detectors 278,9501.1.1.2.2.2 Probe testing 12,0001.1.1.2.2.3 H wedge substrate 43,0611.1.1.2.2.4 H disk fixtures 19,7401.1.1.2.2.5 H wedge fabrication 44,0261.1.1.2.2.6 H Disk Support 63,2091.1.1.2.3 Spares 87,0361.1.1.3 Barrels 2,567,7361.1.1.3.1 Single Sided 218,1621.1.1.3.2 Single Sided Spares 284,8031.1.1.3.3 2 Degree 1,034,7471.1.1.3.5 90 Degree 395,3071.1.1.3.7 Probe Testing 209,6471.1.1.3.8 Berylium substrates 138,4501.1.1.3.9 Ladder Fixtures 47,0281.1.1.3.10 Barrel assembly fixtures 23,5231.1.1.3.11 Ladder fabrication 38,7911.1.1.3.12 Bulkheads 177,2781.1.1.4 Readout IC's 578,7241.1.1.4.1 F disk 155,9571.1.1.4.2 H disk 88,7441.1.1.4.3 Layer 1 27,7331.1.1.4.4 Layer 2 49,9191.1.1.4.5 Layer 3 55,4651.1.1.4.6 Layer 4 99,8371.1.1.4.7 Chip testing 37,8691.1.1.4.8 Spares 63,2001.1.1.5 Readout System (Detector to Port Card) 2,622,9831.1.1.5.1 Disk HDI 150,4191.1.1.5.2 Barrel HDI 347,4491.1.1.5.3 HDI assembly and test 344,2161.1.1.5.4 Low Mass Cables 682,0341.1.1.5.5 High Mass Cables 425,7361.1.1.5.6 Transition Card 113,4601.1.1.5.7 Bias Voltage System 80,6691.1.1.5.8 Interface board 479,0001.1.1.6 Mechanical Support, Services 114,5821.1.1.6.1 Half-cylinder 32,0001.1.1.6.2 Installation fixtures 10,0001.1.1.6.3 Cooling system 42,5821.1.1.6.4 Air system 10,0001.1.1.6.5 Monitoring system 20,0001.1.1.7 Detector Assembly, Installation 40,0001.1.1.7.1 Silicon install fixturing 15,0001.1.1.7.2 Silicon Supports 15,0001.1.1.7.3 Installation services 10,000
CostCost