the zeus microvertex detector

The The ZEUS ZEUS

Microvertex Microvertex DetectorDetector

Tobias HaasTobias Haas

Deutsches ElektronensynchrotronDeutsches Elektronensynchrotron

ZEUS MVD Group: Bonn Univ., DESY-Hamburg, DESY-Zeuthen, Hamburg Univ., KEK-Japan, NIKHEF, Oxford Univ., Padova, Torino, Bologna, Firenze Univ. and INFN, UCL.

MVD Tutorial, Tobias Haas, DESYMVD Tutorial, Tobias Haas, DESY


Today:Today:

MotivationMotivationHardwareHardwareDAQ & R/ODAQ & R/ODQMDQMRadiation monitoringRadiation monitoringAlignment/TrackingAlignment/TrackingSummarySummary


Requirements, Constraints, HistoryRequirements, Constraints, History• ConstraintsConstraints:

* Fit into existing ZEUS detector, < Central tracker inner diameter (~32 cm) > elliptical beampipe (max. (max. ~12 cm)

* Bunch crossing time 96 ns* Operation at room temperature* Extended interaction region in z direction

• Requirements:* < 100 μm impact parameter resolution:

< 20 μm intrinsic point resolution, 3 spatial measurements in two projections

for each track, High (>97%) track efficiency.

• History:* 1997: Approval * 1997 – 2000: Construction* 2000: First Cosmics* 2001: Installation is ZEUS


PhysicsPhysics

Charm

Beauty


MVD in NumbersMVD in Numbers 3(2) Barrel layers, 4 forward planes 3(2) Barrel layers, 4 forward planes 38 mm < 38 mm < RR < 247 mm < 247 mm -300 mm < -300 mm < ZZ < 750 mm < 750 mm 7.67.60 0 < < θθ < < 16016000

Radiation < 300 kRadRadiation < 300 kRad 207360 channels207360 channels >99% single hit efficiency>99% single hit efficiency Currently:Currently:

ca 12k dead channels (5.7%)ca 12k dead channels (5.7%) 50 – 60 50 – 60 μμm single hit resolution (goal: 20 – 30 m single hit resolution (goal: 20 – 30 μμm)m) 130 – 150 130 – 150 μμm vertex resolution (goal: < 100 m vertex resolution (goal: < 100 μμm)m)


The forward section:The forward section:• 4 wheels 4 wheels • each one composed by 2 each one composed by 2

layers of 14 Si detectorslayers of 14 Si detectors• Total of 112 hybrids, Total of 112 hybrids,

>50k channels >50k channels

The barrel section:The barrel section:• 30 ladders 30 ladders • each one composed of 5 each one composed of 5

modules of 4 Si detectorsmodules of 4 Si detectors• Total of 300 hybrids, Total of 300 hybrids,

>150k channels >150k channels

The read section:The read section:• Cooling pipes and Cooling pipes and

manifolds manifolds • Distribution of FE, slow Distribution of FE, slow

control and alignment control and alignment cablescables

Overview of the ZEUS MVDOverview of the ZEUS MVD

All cables in a Faraday cageAll cables in a Faraday cage


• Five modules are mounted on a carbon fiber support structure to form a ladder.

• The Si planes, Hybrids and Cabling are located on the 3 planes of the ladder

• 30 ladders, in 3 planes, are positioned around the elliptical beam pipe in the MVD barrel detector

• Single sided n-doped silicon sensors, 300 μm thick, p+ strip implants,

• Every 6th read out (120 μm R/O pitch),

• RΦ and Z sensors are ganged,

• Two planes are glued together to form a module with x-y readout.

• Helix3.0 analog R/O chip (Heidelberg/NIKHEF)

64 mm

125 mm BarrelBarrel


• The forward wheels have differently shaped detectors (trapezoidal with two different sizes to accommodate the beam pipe),

• Two layers of single sided detectors, same pitch and construction as in the barrel,

• strips cross at an angle of 26°.

• Same electronics and connectivity as in the barrel

Forward WheelsForward Wheels


Sensor/RO/ModuleSensor/RO/ModuleSensor (Design)Sensor (Design)

Helix (RO)Helix (RO)Half ModuleHalf Module


per barrel layerper barrel layer


Patch BoxPatch Box

to detectorto detector

To

pla

tfo

rmT

o p

latf

orm


Other ComponentsOther ComponentsRacks close to Veto wall areaRacks close to Veto wall area

HV/LVHV/LV

ADCsADCs

Cooling/SCCooling/SC


SignalsSignals

analog signalanalog signal

digitized signaldigitized signal

S/N S/N ~12-15~12-15


dE/dxdE/dx


• Disabled ChipsC1L05M0 Hlx 4-7C1L07M0 AllC1L07M4 Hlx 4-7C2L00M3 Hlx 5C2L01M0 Hlx 4-7C2L02M4 AllC2L05M0 Hlx 4-7C2L09M4 Hlx 4-7C2L15M4 Hlx 4-7

• Masked in DAQ since last Mar. C1L00M2 AllC1L02M2 AllC2L09M2 Hlx 4W3S11 All

Detector Status (Pedestal run)Detector Status (Pedestal run)Barrel MVD

Forward MVD


Detector Monitoring and Status:Detector Monitoring and Status:• Dedicated runs (taken daily or when machine schedule allows):Dedicated runs (taken daily or when machine schedule allows):

• Pedestals (noise)Pedestals (noise)• Test pulse runs (gain and timing)Test pulse runs (gain and timing)• IV curves (bulk damage)IV curves (bulk damage)• Laser alignment (mechanical stability)Laser alignment (mechanical stability)

• Online DQM:Online DQM:• Parasitic monitoring: Parasitic monitoring:

• occupancies, occupancies, • cluster charges and widthscluster charges and widths

• Immediate feedback for shiftcrew (hip)Immediate feedback for shiftcrew (hip)• Offline DQM:Offline DQM:

• Dedicated analysis of archived data before reconstruction:Dedicated analysis of archived data before reconstruction:• Occupancies,Occupancies,• Cluster charges and widthsCluster charges and widths• Hit mapsHit maps

• Bad/Noisy channel maps for reconstruction (Bad/Noisy channel maps for reconstruction (→ gaf)→ gaf)

All ResultsAll Results

DQMDQM

DBDB

zx-Querschnitt

4x2 PIN diodes 4x2 PIN diodes

-100 cm110 cm

BMVDFMVD

z=160 cm -120 cm

-130 cm

4 RadFET

X

Z

4 RadFET8 RadFET

8 RadFET

PIN diodes: Instantaneous dose from signal current (photo effect) → beam dump

RadFETs: Integrated dose (Rad damage in FET → shift in threshold voltage)

Radiation MonitoringRadiation Monitoring

-60 cm


-1.1m-1.1m

-0.6m-0.6m

-1.3m-1.3m-1.7m-1.7m

RA

DF

ET

Dos

esR

AD

FE

T D

oses


Radiation EffectsRadiation EffectsSignal: Signal: ↓↓Noise: ↑ Noise: ↑ Sensor leakage Sensor leakage

currents: ↑currents: ↑ Sig

nal

(A

DC

Co

un

ts)

Sig

nal

(A

DC

Co

un

ts)

No

sie

(AD

C C

ou

nts

)N

osi

e (A

DC

Co

un

ts)

August 2002August 2002

August 2002August 2002

Lea

kag

e (

Lea

kag

e ( μμ

A)

A)


bad

Bad

Mod

ules

Bad

Mod

ules

Sen

sor L

eakage

Sen

sor L

eakage

Cu

rrents

Cu

rrents

(measu

res radatio

n

(measu

res radatio

n

do

se)d

ose)

rearrearforwardforward

forwardforward


Bad ChannelsBad Channels


??


MVD Reconstruction SuiteMVD Reconstruction Suite MVRECON MVRECON (table: MVRECC)(table: MVRECC)

Standalone MVD reconstructionStandalone MVD reconstruction Calibrations, Dead Channel TreatmentCalibrations, Dead Channel Treatment ClusteringClustering

VCRECON, Pass 1 VCRECON, Pass 1 (table: ZTPRHL)(table: ZTPRHL) Pattern RecognitionPattern Recognition First Track FitFirst Track Fit

KFRECON KFRECON (table ZTTRHL, ZTTRPRM)(table ZTTRHL, ZTTRPRM) Kalman Filter + Track FitKalman Filter + Track Fit

VCRECON, Pass 2VCRECON, Pass 2 Primary and Secondary Vertexing Primary and Secondary Vertexing

Iteration is possible… … but not reallyforeseen …


MVRECONMVRECON

Strips

AD

C

Counts

Strip Threshold

Cluster Threshold

Cluster

• Clustering a la “Online”• Cluster + Strip Threshold• Allow one strip below threshold• Add on the two side strips below threshold

• Position Reconstruction


EfficienciesEfficiencies

ΦΦ

ΦΦ

SimulatioSimulationn

DataData

#

#

Tra

cks

Tra

cks

> 4 MVD hits> 4 MVD hits

> 2 MVD hits> 2 MVD hits

All CTD tracksAll CTD tracks

Note: Acceptance holesNote: Acceptance holes

Efficiency estimates from NC DIS: (Tracks in CTD and MVD fiducial)Efficiency estimates from NC DIS: (Tracks in CTD and MVD fiducial)

> 4 MVD hits> 4 MVD hits > 2 MVD hits> 2 MVD hits

DataData 91.4% 91.4% 99.3% 99.3%

MCMC 93.8% 93.8% 99.3% 99.3%


Propaganda EventsPropaganda Events

QQ22 1200 GeV 1200 GeV2 2 Charged CurrentCharged Current

QQ22 4500 GeV 4500 GeV2 2 Charged CurrentCharged Current

QQ22 2800 GeV 2800 GeV2 2 Neutral CurrentNeutral Current


AlignmentAlignment

• 3 Step process:3 Step process: Survey of ladder positions before Survey of ladder positions before

installation in the lab,installation in the lab,

Final alignment using cosmic data,Final alignment using cosmic data,

Monitoring of stability using an in situ Monitoring of stability using an in situ laser system with semi-transparent laser system with semi-transparent position sensors.position sensors.


Current AlignmentCurrent AlignmentG

lob

al a

lign

men

tG

lob

al a

lign

men

tIn

tern

al a

lign

men

tIn

tern

al a

lign

men

t

σσ=335=335μμmm

σσ=289=289μμmm

σσ=97=97μμmm

σσ=64=64μμmm

σσ=1604=1604μμmm

σσ=1502=1502μμmm

σσ=116=116μμmm

σσ=47=47μμmm

Track ResidualsTrack ResidualsImpact ParameterImpact Parameter


Alignment … commentsAlignment … comments Only 1 (!) Only 1 (!)

alignment existsalignment exists Barrel could be Barrel could be

better… better… … … but the wheels but the wheels

have not even have not even been touched.been touched.

Still dependent on Still dependent on standalone cosmic standalone cosmic runsruns

cosmics taken cosmics taken during beam are during beam are being studied …being studied …

BarrelBarrel

WheelsWheels


Questions to the alignmentQuestions to the alignment

alignment procedurealignment procedureposition reconstruction in mvreconposition reconstruction in mvreconEffects of magnetic fieldEffects of magnetic field long term stabilitylong term stability

Peformance Estimate (R. Peformance Estimate (R. Mankel)Mankel)

D* tagged events allow to D* tagged events allow to investigate the distance-of-investigate the distance-of-closest approach (DCA) of the closest approach (DCA) of the helices of Khelices of K–– and and ++

DCA resolution-per-track DCA resolution-per-track ((DCADCA//√2) is a measure related √2) is a measure related to the impact parameter to the impact parameter resolutionresolution

independent of vertexingindependent of vertexing averaged over longitudinal (Z) averaged over longitudinal (Z)

and transverse (Dand transverse (DHH) resolutions) resolutions

Compare to H1 published Compare to H1 published impact parameter resolutionimpact parameter resolution

IPIP=33=33m m (90 (90 m /pm /pTT))

At MC level our resolutions At MC level our resolutions look reasonablelook reasonable

Data: alignment key issueData: alignment key issue

ZEUS data (2004 e+)

ZTT

ZEUS MC ZTT

H1 IP resolution(1/pT 1.4/p)

MCMC


Alignment Monitoring: Laser AlignmentAlignment Monitoring: Laser Alignment

• 5 laser beams (780nm, 5 mW), 5 laser beams (780nm, 5 mW), 7 sensors/beam, 7 sensors/beam,

• Sensor gives position to Sensor gives position to 1010μμm,m,• Data taken once per fill,Data taken once per fill,• Monitor deformations and define Monitor deformations and define

period of stability.period of stability.

Typical Example of MeasurementTypical Example of Measurement


Stability < 20 Stability < 20 μμmm


!!


SummarySummary• ZEUS MVD has completed the commissioning ZEUS MVD has completed the commissioning

phase, i. e. design goals have been reached:phase, i. e. design goals have been reached:• Reliable and well monitored detector operation Reliable and well monitored detector operation

(Data quality, radiation, alignment),(Data quality, radiation, alignment),• High tracking efficiency (>99%),High tracking efficiency (>99%),• Precision needs to reach the goal (Impact Precision needs to reach the goal (Impact

parameter resolution parameter resolution < 100 < 100 μμm m ).).• Dead channel development is worryingDead channel development is worrying• Irradiation is under control but a constant concern.Irradiation is under control but a constant concern.• Alignment work needs to progressAlignment work needs to progress

the zeus microvertex detector

Documents

7c2l00m3 hlx 5c2l01m0

7c2l09m4 hlx

7c2l15m4 hlx

disabled chipsc1l05m0

7c1l07m0 allc1l07m4

7c2l02m4 allc2l05m0

track efficiency

single hit resolution