lhcb vertex locator & displaced vertex trigger vertex detector design test beam results ...

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LHCb LHCb VE VE rtex rtex LO LO cator cator & Displaced Vertex & Displaced Vertex Trigger Trigger Vertex Detector Vertex Detector Design Test Beam Results Displaced Vertex Trigger Displaced Vertex Trigger Algorithm Test Beam Emulation Conclusions Conclusions Summary Future Plans Chris Parkes, CER Beauty ‘99

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Page 1: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

LHCb LHCb VEVErtex rtex LOLOcator & cator & Displaced Vertex TriggerDisplaced Vertex Trigger

Vertex Detector Vertex Detector Design Test Beam Results

Displaced Vertex TriggerDisplaced Vertex Trigger Algorithm Test Beam Emulation

ConclusionsConclusions Summary Future Plans

Chris Parkes, CERN

Beauty ‘99

Page 2: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

LHCb DetectorLHCb Detector

Page 3: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

Resolution Resolution

Secondary VerticesSecondary Vertices

B taggingB tagging

Rejection of Rejection of backgroundbackground

Primary vertex Primary vertex resolution 40 resolution 40 mm

Page 4: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

GeometryGeometry

10cm

Detectors separated 6cm during injection

series of discs

smalloverlap

Page 5: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

Vertex LocatorVertex Locator

• Detector Length 1m

• Station spacing varying

from 4 - 12cm

• Phi Overlap of detectors

• Each Station has an R and

a Phi measuring detector

• Stereo angle between

successive Phi Detector layers

Page 6: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

r-measuringdetectors

-measuringdetectors

Prototype DesignPrototype Design

5 ° “stereo” tilt

Both detectors utilize a double metal layer to readout inner strips whilst keeping electronics outside active area.

r-detectors

-detectors

Page 7: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

New DesignNew Design 180 degree R 180 degree R

& Phi & Phi DetectorsDetectors

2048 strips2048 strips

Smooth Smooth variation in variation in pitchpitch

Ready in Ready in AutumnAutumn

16 chip Hybrid16 chip Hybrid

Page 8: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

MechanicsMechanics

Page 9: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

Vacuum VesselVacuum Vesselmanipulators

window

TopHalf

primary vacuum

vessel

detectors100cm

RF shieldvacuum barrier

Page 10: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

Radiation EnvironmentRadiation Environment

1013

1014

1 M

eV e

quiv

alen

t neu

tron

s/cm

2

1 2 3 4 5 6cm

station 6

Dose after 1yr Including effects of Including effects of walls, vesselwalls, vessel

High doses at tipsHigh doses at tips (1/r2)

Detectors IrradiatedDetectors Irradiated Test-Beam

September

n+ on n Silicon as n+ on n Silicon as base solutionbase solution

Page 11: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

ModellingModelling

Cooling Required

Electric Field Distortions

Radiation Response

Page 12: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

SoftwareSoftware

LHCb will use C++LHCb will use C++BUT Technical Proposal work was in FORTRAN

Test Beam Test Beam used to gain experience with new language and Root

All reconstruction software in C++

Cluster Making, Event Display, Track Fit, Alignment, Noise Studies...

Software Designed for future useSoftware Designed for future useboth useful code, and class design

Page 13: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

Trigger LevelsTrigger Levels

Page 14: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

Second Level Trigger Second Level Trigger Vertex AlgorithmVertex Algorithm

Second Level Trigger Second Level Trigger Vertex AlgorithmVertex Algorithm

IDEA Separation of minimum bias events and B events by

using the signature of displaced secondary vertices.

AIM Minimum bias retention of less than 4% and a signal

efficiency of more than 50%.

Boundary Conditions Input event rate of 1 MHz or 2Gbytes/second . Average execution time of about 250 microseconds.

Implementation benchmark results show can be performed by 120 1000

MIP processors

Page 15: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

Present AlgorithmPresent AlgorithmPresent AlgorithmPresent Algorithm 2d2d

Track finding using triplets of r-clusters track search starts in inner r sector

Primary vertex reconstruction, x y z, by crossing tracks of opposite phi-sectors

x y - resolution given by phi-sector Selection of tracks with large impact parameter Rejection of pile-up events

z

r

Page 16: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

Algorithm cont.Algorithm cont.Algorithm cont.Algorithm cont.

3d3d Add phi info. for large impact parameter tracks

ambiguities resolved by stereo angle and impact parameter in xy-projection

find two track combinations which are close calculate probability that one of the two tracks

originate from the primary vertex based on impact parameter and geometry

calculate total L1 probability by multiplying the individual probabilities

Page 17: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

Present PerformancePresent PerformancePresent PerformancePresent Performance

2d and 3d track reconstruction efficiency of 98% and 95%.

Primary vertex resolution of 80micron and 20micron for z and x/y.

Page 18: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

Test BeamTest BeamSpring ‘98Spring ‘98

12 Silicon Planes

Slow Electronics

Page 19: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

Vertex Trigger Vertex Trigger PeformancePeformance

Use Targets to Use Targets to simulate Primary simulate Primary VertexVertex

Resolution Resolution Simulation 80m Test Beam

Extrapolated 80m

Assess sensitivity Assess sensitivity to detector to detector misalignmentsmisalignments

Page 20: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

Artificial B eventsArtificial B events

Virtual BVirtual B ! ! Five events form one target

“minimum bias” One From next target

B event

Good PerformanceGood Performance

Page 21: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

OverviewOverviewof theof the

readoutreadoutschemescheme

Analogue

readout

FE Rad. Hard

>2Mrad/yr

FADC + L1

buffers 10m away

Processing in

DSPs after L1 accept

Front End Chip

DMILL- SCTA

or

0.25m CMOS-

BEETLE

Page 22: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

LHC Speed Readout LHC Speed Readout ChipChip

Test-Beam Spring ‘99Test-Beam Spring ‘99 AimAim

Evaluate Evaluate

performance performance

of detectorof detector

equipped withequipped with

SCT128A 40MHzSCT128A 40MHz

FE chipFE chip

SetupSetup

6 plane Telescope6 plane Telescope

+ 2 Test Detectors+ 2 Test Detectors

Page 23: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

Test-Beam ResultsTest-Beam Results

Clear Signal ObservedClear Signal Observed Correlated with reference TelescopeCorrelated with reference Telescope

Page 24: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

Time ResponseTime Response

Rise Time ~ 25nsRise Time ~ 25ns

Pulse Remaining afterPulse Remaining after

25ns ~ third of Signal25ns ~ third of Signal40% of LHCb events are40% of LHCb events are

preceded by an eventpreceded by an event

simulation of Bsimulation of BTrigger efficiencyTrigger efficiency

drops above 30%drops above 30%

overspilloverspill

Signal:Noise ~ 20:1Signal:Noise ~ 20:1

Page 25: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

ConclusionsConclusions

Prototype Detectors Tested Prototype Detectors Tested New Design New Design

Displaced Vertex Trigger Displaced Vertex Trigger Future Work Future Work …..…..

So far the project is flying...

Page 26: LHCb VErtex LOcator & Displaced Vertex Trigger  Vertex Detector Design Test Beam Results  Displaced Vertex Trigger Algorithm Test Beam Emulation  Conclusions

Beauty ‘99 Chris Parkes

MilestonesMilestones

2000 : Full Half station at 40MHz

2001 : Technical design Report

2003 : Construction

2004 : Commissioning

2005 : Start Data Taking

But there is still a long way to cycle…..