20 April 2002 Bill LeeAPS

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The D0 Silicon Track Trigger

Bill LeeFlorida State University

20 April 2002 Bill LeeAPS

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STT People and Institutions• Boston University

– Ulrich Heintz, Meenakshi Narain– Evgeny Popkov, Lars Sonnenschein, Jodi

Wittlin– Kevin Black, Sarosh Fatakia, Lorenzo

Feligioni, Alex Zabi– Eric Hazen, Bill Earle, Shouxiang Wu

• Columbia University– Hal Evans– Georg Steinbrück– Tulika Bose– An Qi

• Florida State University– Horst Wahl, Sue Blessing, Stephen Linn,

Harrison Prosper– Bill Lee, Sylvia Tentinto-Repond– Reginald Perry, Arvindh Lalam, Shweta

Lolage• SUNY Stony Brook

– John Hobbs– Wendy Taylor– Huishi Dong– Chuck Pancake, Bonnie Smart, Jane Wu

20 April 2002 Bill LeeAPS

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D0 Central Detector Upgrade• New silicon tracker, new fiber tracker, new preshower, and

a new 2T superconducting solenoid.

20 April 2002 Bill LeeAPS

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Silicon Microstrip Tracker (SMT)

- ~800,000 total readout channels- 6 barrels (4 layers)

- ~390,000 axial channels- ~220,000 stereo channels

- 12 interspersed (F-)disks - 4 external large area (H-)disks for

forward tracking (2 < |η| < 3)

~ 2.4 m

SMT half cylinder

20 April 2002 Bill LeeAPS

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D0 Central Fiber Tracker (CFT)• ~12m long clear light-guides to Visible Light Photon Counters (VLPC)

under detector• 8 layers of axial and stereo fibers (20 < r < 51 cm), 77k channels

VLPC

20 April 2002 Bill LeeAPS

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D0 Trigger System

• L1CTT– Provides

tracks from axial CFT fibers

• SMT unused until L3

L2FW:Combined objects (e, µ, j)

L1FW: towers, tracks, correlations

L1CAL

GlobalL2

L2CFT

L2PS

L2Cal

L1CTT

L2Muon

L1Muon

L1FPD

Detector L1 Trigger L2 Trigger7 MHz 5-10 kHz

CAL

FPSCPS

CFT

SMT

Muon

FPD

1000 Hz

20 April 2002 Bill LeeAPS

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Trigger System with STT• What if we

used the SMT to improve the tracks from the CTT?

L2FW:Combined objects (e, µ, j)

L1FW: towers, tracks, correlations

L1CAL

L2STT

GlobalL2

L2CFT

L2PS

L2Cal

L1CTT

L2Muon

L1Muon

L1FPD

Detector L1 Trigger L2 Trigger7 MHz 5-10 kHz

CAL

FPSCPS

CFT

SMT

Muon

FPD

1000 Hz

20 April 2002 Bill LeeAPS

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Track Reconstruction at L2

• We could get:– Impact

parameter– Improved pT

resolution– Fake track

reduction

20 April 2002 Bill LeeAPS

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Conceptual Design• L1CTT tracks in CFT

– Define road in SMT

• Find clusters in SMT hits• Select SMT clusters in

roads• Fit trajectory to

L1CTT+SMT hits. • Send results to L2

roaddata

SMTdata

SiliconTriggerCardSiliconTriggerCard

SiliconTriggerCardSiliconTriggerCardSiliconTriggerCard

FiberRoadCard

SiliconTriggerCard

TrackFit

CardL2CTT

20 April 2002 Bill LeeAPS

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Fiber Road Card (FRC)

• Communicates with trigger framework and broadcasts control info to other cards.

• Fans out track data to all other cards

• manage L3 buffers– Controls the readout to

L3

20 April 2002 Bill LeeAPS

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Silicon Trigger Card

• Receives raw data from SMT

• Finds clusters in axial and stereo strips

• Associates tracks with axial clusters

• Outputs clusters with tracks

Strip reader

Cluster finder

Hit filter

SMTL1CTT

RoadLUT

SCL

L3

L3

TFC via serial link

from FRC via serial link

control logic

L3

channel logic (x8)

20 April 2002 Bill LeeAPS

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STC Prototype RoadLUT

RoadLUT

RoadL

UT

RoadL

UT

control logic(8x) channel logic(Xilinx Virtex E)

800k gates1.1 Mbits RAM560 pin BGA

accommodatesall 8 channels

need 1/STC

control logic(8x) channel logic(Xilinx Virtex E)

800k gates1.1 Mbits RAM560 pin BGA

accommodatesall 8 channels

need 1/STC

20 April 2002 Bill LeeAPS

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Track Fit Card (TFC)• One per 30 degree

sector• Inputs tracks from

FRC and associated clusters from STC

• Farms each track out to one of eight DSPs

• Outputs input track list and expanded track list to L2

TI6202/3 (300 MHz)DSPs

20 April 2002 Bill LeeAPS

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Track Fit Card (TFC)• require hits in

– at least 3 of the 4 SMT layers

– in same 30 degree sector– in at most 2 adjacent barrels

• choose hits – closest to trajectory defined

by CFT and origin• linearized χ2 fit

– φ(r) = b/r + κr + φ0– drop worst hit and refit if 4-

hit χ2 bad

20 April 2002 Bill LeeAPS

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Summary

• STT will provide D0 with the ability at L2:– to reduce the background signal– to improve pT resolution– to cut on an impact parameter

• Production of boards is underway.• Our goal is to be operational in early

summer.