The DØ Silicon Microstrip Tracker (SMT)

DDThe DØ Silicon The DØ Silicon

Microstrip Tracker Microstrip Tracker (SMT)(SMT)

Breese Quinn, FNAL

Vertex2001

September 24, 2001

(presented by Frank Lehner, Universitaet Zuerich)

Design Production & Assembly

Readout Installation & Commissioning

First Results

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SMT Design

4-layer barrel cross-section

Barrels F- Disks H- Disks

Channels 387072 258048 147456

Modules 432 144 96

Si Area 1.3 m2 0.4 m2 1.3 m2

I nner R 2.7 cm 2.6 cm 9.5 cm

Outer R 9.4 cm 10.5 cm 26 cm

SMT StatisticsSMT Statistics

6 Barrels

12 F Disks

4 H Disks

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SMT Design

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SMT Design

Require good 3D track reconstruction performance for high-pT (top, Higgs, EW, NP) and low-pT (B) tracks out to || < 3

Momentum resolution less than 10% at pT = 1 GeV/c

Impact parameter resolution within 30 m

Forward H disks are employed to achieve these resolutions at high ||

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Production & Assembly: Devices

Ladders3-chip: 72 single-sided, axial ladders in the two outer barrels

6-chip: 144 double-sided, axial/90° ladders in the four inner barrels

9-chip: 216 double-sided, axial/2° ladders in all barrels

Ladders have a mechanical accuracy of 2-5 m

WedgesF Disks: 144 double-sided, ±15°, 6+8 chip wedges

H Disks: 96×2 back-to-back single-sided, ±7.5°, 6 chip wedges

Wedges have a mechanical accuracy of 5-10 m

SVX IIe chip128 channel 8-bit digital chip, with 32 cell pipeline depth

1.2 m rad-hard technology

106 MHz digitization, 53 MHz readout

Rise time set to integrate 99% of charge in 100 ns

Over 2.3 million wirebonds were made to chips

9-chip ladder9-chip ladder

H wedgeH wedge

SVX IIe chipSVX IIe chip

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Production & Assembly: Testing

Probe TestDebug bad strips (broken capacitors), bonds, chips, etc.Determine the V-I characteristics of the sensors

Measure V-max p-side breakdown voltage (micro-discharge effect)

Burn-inBias the ladder or wedge and test the readout for 72 hoursMeasure pedestals, noise, gain and check sparse readout

LaserExpose biased detectors to a narrow laser scanMeasure the depletion voltage and leakage currents and identify dead channels

Readout tested again after the detector is mounted on a barrel or disk

V-max

Fail

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Production & Assembly: Failure Modes

Sensor lithography defectsA silicon manufacturing problem produced p-stop isolation defects in the 90° stereo ladders. This resulted in a 30% yield from the manufacturer.

Microdischarge effectWith negative p-side bias on double-sided detectors, we observed microdischarges producing large leakage currents and noise at a breakdown voltage. The effect occurs along the edges of the p implants, where large field distortions and charge accumulations result from misalignment of electrodes with implants.Effect moves to n-side after type inversion.

6399 noise on n-side

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

0 20 40 60 80 100 120 140 160

Total HV

AD

C C

ou

nts

-10V

-30V

-50V

-70V

-90V

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Production & Assembly: Detector Quality

Detector classification:Dead channel: < 40 ADC count response to laserNoisy channel: > 6 ADC count pedestal widthGrade A: less than 2.6% dead/noisy channelsGrade B: less than 5.2% dead/noisy channels

Only used mechanically OK Grade A and B detectors

6-Chip 6-Chip LaddersLaddersTitle:

chip6_pn_dead.epsCreator:HIGZ Version 1.25/05Preview:This EPS picture was not savedwith a preview included in it.Comment:This EPS picture will print to aPostScript printer, but not toother types of printers.

Channel Fractions (%)Channel Fractions (%)

Dead Noisy

Barrel

1 1.5 0.6

2 1.6 0.5

3 1.0 0.3

4 1.3 0.3

5 1.2 0.4

6 2.0 0.2

F Disks 0.5 0.3

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Production & Assembly: Alignment

Internal alignment was accomplished using a CMMmachine that aligns ladders and wedges to < 20 m.e.g. Rotation along long axisof ladder ( = 10 m 3 m error on impact parameter)

Barrel 1 Barrel 1 RotationsRotations

(mm)

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SMT Readout: Data Flow

PlatformPlatformPlatformPlatform

SEQ

SEQ

SEQ

SEQ

SEQ

SEQ

3/6/8/9 Chip HDI

Sensor

8’ Low Mass Cable

VRB Controller

Optical Link1Gb/s

V

B

D

V

R

B

V

R

B

V

R

B

68k/PwrPC

Bit3

PC

SDAQL3MPM

VME

1553

HV / LV

Adapter Card

I,V,T Monitoring

KSU

Interface Board

25’ High Mass Cable (3M/50 conductor)

CLKs CLKs

SEQController

Serial Command Link

~19’-30’ High Mass Cable (3M/80 conductor)

Detector volumeDetector volumeDetector volumeDetector volume

Counting HouseCounting HouseCounting HouseCounting House

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SMT Readout: Electronics

Interface Boards8 crates (144 boards) located inside the detector volumeRefresh signals and adjust timingSVX monitoring and power managementBias voltage distribution

SEQuencers6 crates (120 boards) located on the detector hall platformUse SVX control lines to effect data acquisition, digitization and readoutConvert SVX data to optical signals

VRBs (VME Readout Buffers)

12 crates (120 boards) located in the counting houseData buffer pending L2 trigger decisionInput @ 5-10 kHz L1 accept rate ~ 50 Mb/s/channelOutput @ 1 kHz L2 accept rate ~ 50 Mb/s

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Installation

Cylinder installation was completed on 12/20/00

A ½ cylinder of 3 barrels and 6 F disks was inserted into each end of the CFT bore

H Disk installation was completed on 2/6/01

The cabling (~15,000 connections) and electronics installation was completed in May 2001

Fiber Tracker

Low Mass Cables

High Mass Cables

SMT

Interface Boards

Calorimeter

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Commissioning

The entire detector has been connected and powered~15% of the devices are not in the readout because the SVX chips cannot be downloaded.

10% ladders, 18% F wedges, 20% H wedgesProblems could be with cables, connectors, chips, etc. We will debug each of them during the October/November shutdown, and expect to recover more than half.

Currently collecting calibration and alignment data

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Comissioning

Online event display for SMT commissioning

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Charge CollectionTitle:clchar_fd05-02-0c_3f_0x66.ps (Portrait A 4)Creator:HIGZ Version 1.26/04Preview:This EPS picture was not savedwith a preview included in it.Comment:This EPS picture will print to aPostScript printer, but not toother types of printers.

A cluster is defined as a contiguous sequence of strips with

Each strip 6 ADC countsCluster 12 ADC counts

Timing setting a-b-c represents a signal delay of (a-1)132 ns + (b-1)18 ns + (c-1)2 nsPreamp bandwith (pabw) sets the integration time

With 396 ns bunch spacing, all charge should be collected with any of the pabw settingsHigher pabw results in lower noise level

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Timing and S/N

Higher preamp bandwith does not significantly reduce noise on n-side

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Title:sig_to_noise.ps (Portrait A 4)Creator:HIGZ Version 1.26/04Preview:This EPS picture was not savedwith a preview included in it.Comment:This EPS picture will print to aPostScript printer, but not toother types of printers.

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Alignment: Residuals

SMT-only tracking with at least 4 hitsMagnet off dataSimilarity of residuals from reconstruction with ideal and survey geometries indicates excellent internal alignment of the SMT

Ideal GeometryIdeal Geometry Survey GeometrySurvey Geometry

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Alignment: SMT & CFT Track Matching

Tracks were found separately in the SMT and the Central Fiber Tracker (CFT)

SMT tracks were extrapolated to the CFT at which point the track offsets were measured

Magnet off data

r = -3 36 m

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J/ Candidate Sample

Sherry Towers

PREL

IMIN

ARY

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Conclusions

Design/ProductionExperience with double-sided detectors has led to the decision to use single-sided silicon for the upgrade.

Should work toward simpler designs in the future. For example, using 6 different sensor types resulted in extensive logistical complications.

Assembly/InstallationAlignment results show that the DØ SMT was assembled and installed extremely well. Congratulations to the SiDet and DAB staff!

CommissioningThe SMT was the first major DØ Upgrade detector system fully operational for Run 2A. More than 85% of the channels were available for readout on startup, and most of the remaining channels will be debugged and recovered by November.

ResultsVery nice calibration (and first look at physics!) results have been produced from the early data, as we continue to better understand our detector.

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Alignment: Beam

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Distance of Closest ApproachDistance of Closest Approachvs. vs. Vertex PositionVertex Position

The DØ Silicon Microstrip Tracker (SMT)

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