TheVeryForwardRegionofthe ILCDetectors Ch.Grah FCALCollaboration - - PowerPoint PPT Presentation

TheVeryForwardRegionofthe ILCDetectors

Ch.Grah

FCALCollaboration LectureSeriesofJAI,Oxford Thursday 15/11/2007

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Contents

TheFCALCollaboration ForwardCalorimetry Overview

–

Beamdiagnostics usingBeamCalandGamCal R&DoftheFCALCollaboration:

– –

Summary

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! !

"#$%"&'

%( )*+%,-

• +.!*/

$%.(( ,- 1$.! ! 2223 .%( )(4- )*+ ++*+

UniversityofColorado,Boulder

$. $5%.

YaleUniversity,NewHaven / %*+ Supportedby: EUROTeV, EUDET, NoRHDIA INTAS DOE ISF Fital

http://www7zeuthen.desy.de/ILC/fcal/

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TheInternationalLinearCollider

~30km Parameters: 500GeV (1TeV upgradepossible) 2x106#cm78sec7" electronpolarization~80% positronpolarization~30%(60%) beamsizes:σ9 ≈ 600nm,σ≈ 6nm, σ: =300m

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DesignoftheForwardRegion

ILCRDR

BeamCal LumiCal GamCal ~185m

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TasksoftheForwardRegion

IP ECal andVeryForwardTrackeracceptanceregion.

• Precisemeasurementofthe

integratedluminosity(L/L~107#)

• Provide27photonveto
• Provide27photonveto
• Servethebeamdiagnostics

usingbeamstrahlungpairs 5mrad ~ 4 m r a d ~ 1 5 m r a d

• Servethebeamdiagnostics

usingbeamstrahlungphotons

' Highprecision,highoccupancy,highradiationdose,fastread7out!

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ForwardRegion(LDC)

VacuumPump BeamCal LumiCal QD0 Graphite Spacefor electronics/connectors cooling Spaceforcables ShieldingTube BPMforFONT Si7pixel

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ForwardRegionOverview

TheFCALCollaboration developstheVeryForward Detectors: LumiCal,BeamCaland GamCal. Duetothesmallbunchsize σx~650nm,σy~5.7nmand thehighbunchcharge, Nx1010/bunch, beamstrahlungbecomes importantattheILC. Thegeometryhastobe carefullyoptimizedto minimizebackgrounddueto thebeamstrahlungpairs.

SID LDC

~185m 3000 1800 mm ZPos 7 110 200 mm ROuter 7 16 60 mm RInner 7 165 350 mm ROuter ~185m 7 GamCal 3550 20 BeamCal 2270 80 LumiCal mm mm ZPos RInner

LDC20mrad

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TheLumiCal

PreciseMeasurementoftheILC‘s luminosity

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PreciseMeasurementoftheLuminosity

Requiredprecisionis: L/L~107#(GigaZ 10;/year) L/L<1076 (e<e7W<W7 10=/year) L/L<1076 (e<e7q<q7 10=/year) Bhabhascatteringee7>ee(γ)isthegaugeprocess:

– !+-/>?>.@σ – )>?.! A"@θ6 – B-/C('"&76D' AE"&7#5

LumiCal BeamCal

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PhysicsBackgroundandBeam7BeamEffect

• 27photoneventsarethemainbackground.
• Wedeterminedanefficientsetofcutsto

reducethebackgroundtothelevelof107#.

• TheBhabhaSuppressionEffect(BHSE)isdue

totheEMdeflectionandenergylossby beamstrahlungoftheBhabhas.Correction needspreciseknowledgeofbeamparameters.

C.Rimbault etal.JINST2:O9001.2007

27photon rejection BHSE

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LumiCalDesign

Si/Wsandwichcalorimeter, 2halfbarrels,30740 layers laserpositionmonitoringsystem

Singledetectorlayer 48azimuthalsectors, eachsectorsubdividedintoradial padsofabout1mrad Eachlayerconsistsof 3.5mmtungstenabsorber, 300msiliconsensorandreadout.

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RequirementsontheMechanicalPrecision

300Om distance 640Om radialoffset 4.2Om innerradius 1.0107# L/L

MCsimulationsofLumiCal:

Deriverequirementsondesign,segmentation,mechanicalprecision andimpactofdifferentmagneticfield/crossingangles.

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LumiCal:Systematics

Headon,14,20mrad X7angleoutgoingbeam 14mrad X7angledetectoraxis 20mrad X7angledetectoraxis

Recommendation: placeLumiCalaroundoutgoing beamandtiltitaccordingly.

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LaserAlignmentSystem

• 1,2
• 1
• 0,8
• 0,6
• 0,4
• 0,2

0,2 0,4 0,6 0,8 100 200 300 400 500 600 700 800 900 1000 x displacement [µm] σx [µm]

Background cut=15 Background cut=25 Background cut=50 Background cut= 90

Temperaturestabilityisanissue. Observedchangesofabout1m/K. IntegrationstudyfortheLASstarted. Twolaserbeamsallowtomeasure displacementsinxyz. σx=0.5m σz=1.5m

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TheBeamCal

ParticleVetoatLowestPolarAngles

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BeamCalDesign

Compactem calorimeterwithsandwich structure:

30layersof1X0

• 3.5mmWand0.3mmsensor

Angularcoveragefrom~5mradto~45mrad Moliére radiusRM ≈ 1cm Segmentationbetween0.5and0.8xRM

BeamCal

Wabsorberlayers Radiationhardsensors withthinreadoutplanes Spaceforreadoutelectronics

LumiCal BeamCal

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BeamCalChallenges

BeamCalwillextend thesensitiveregion tolowestpolarangles. Challenge: Detectsinglehigh energeticparticle

• ntopofa

backgroundof104 low energetice+e7 pairs. BeamCalservesalsoas partofthebeam diagnosticssystem, providinga ‘beamstrahlungpair’ informationtothe feedbacksystem.

Physicssignal: e.g.SUSYsmuon production Backgroundsignal: 27photonevent,mayfake theuppersignaliftheelectron isnotdetected.

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ParticleVeto

Wedevelopedalgorithmsto efficientlyvetosinglehigh energeticparticlesdownto lowestpolarangles. Weinvestigatedtheimpact

• fdifferentlayouts,cell

sizes,etc.. Weneedradiationhard sensorswithalargedynamic rangeO(104).

averagetileenergysubtracted

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GamCal

MeasuringBeamstrahlungPhotons

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GamCalDesign

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GamCalDesign(cont.)

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Beamdiagnostics

UsingBeamCalandGamCal

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Beamdiagnostics

• Obtain asmuch information about the collision aspossible.
• BeamCalmeasures the energy ofpairs originating from

beamstrahlung.

• GamCalwillmeasure the energy ofthe beamstrahlung

photons.

• 1. Investigatecorrelationtolearn

howwecanimprovethe beamdiagnostics and

• 2. Defineasignalproportionalto

theluminositywhichcanbefed tothefeedbacksysteminreal timeandwithalowlatency.

100 200 300 400 500 600 1 2 3 x 10

34

Bunch # Luminosity / cm-2s-1

G.White QMUL/SLAC RHUL & Snowmass presentation

positionandanglescan

SimulationoftheFastFeedbackSystemoftheILC.

1. Standardprocedure (using BPMs) 2. Include pairsignal (N)asadditionalinput tothe system

Increase ofluminosity of107 15%

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IncludeGamCalInformation

Ratio of Energies (BCAL)

0,02 0,04 0,06 0,08 0,1 0,12 0,14

• 300
• 200
• 100

100 200 300

• ffset_y/2 (nm)

E_pairs(BCAL)/E_gam ma (10^-6)

0,5 1 1,5 2

Luminosity (10^34 cm^- 2/s)

Studies by M.Ohlerich complementary information from 1. totalphoton energy vs vertical offset 2. BeamCalpairenergy vs vertical offset ratio ofE//E vs vertical offset is proportionaltothe luminosity similar behaviour for vertical angle, vertical waist shift …

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AdvancedBeamdiagnostics

Whatelsecanwelearnaboutthecollision? Usethebeamstrahlungpairandphotonsignalto determineandimprovetheacceleratorparameters.

– /!%/% !/%%! 5 – *fast 9!/-' !:Cσxσy σzD Cεx εyD %%Cx yD %Cx yD Cαh,αv φD (/!C.bD

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Concepts ofthe BeamstrahlungAnalysis

SimulateCollision with/ 1.)nominalparameterset 2.)withvariationofaspecific beamparameter (e.g.σx,σy,σz,σx,∆σy, ∆σz) G.White:2nd orderdependencies Producephoton/pairoutput ASCIIFile RunfullGEANT4simulation BeCaS andcalculateenergy depositionpercell (geometryandmagneticfielddependent) CalculateObservablesand writesummaryfile Dotheparameterreconstructionusing 1.)linearapproximation(MoorePenroseInversionMethod) 2.)usingfitstodescribenonlineardependencies A.Sapronov:BeCaS1.0 LC7DET720057003

Diagnostics ofColliding Bunches from Pair Production andBeam Strahlungatthe IP

AchimStahl include beamstrahlung photons (Eγ,total)

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MoorePenroseMethod

Observables Observables

BeamPar

Taylor Matrix

nom

= + *

• bservables:

–

• –

% – +5 – @@ – C ≥ #D@ – @. – / – +5/ – %@! – /C9D

beamparameters(diffandav)

– !: –

• –

!%% – % – ! – /% – !%/

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Beam ParameterReconstruction

&5&8E F5"# 7 #5G8 σ 0.010 4.55 7 307.98

• 20mradDID

&5&"G5 70.071 &5&8E 70.001 &5&"= 0.002 rad α9 ""5F& 73.84 F5"6 4.57 "#58# 4.77 nm 9 85"= 9.94 7 7 G5=" 11.99 10 1076mrad ε9 "5=E 301.09 "5=; 299.80 #5E= 300.75 300 m σ: σ

• σ
• σ
• Nom

. Unit BP 14mradantiDID + Ephot 20mrad DID+Ephot 2mrad(old)

Singleparameter reconstruction using whole calorimeter data A.Sapronov Photonenergy can be provided by GamCal.

EUROTeV7Report720077006 Ch.Grah,A.Sapronov

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FCALR&D

RadiationHardSensorsandReadoutElectronics

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RadiationHardSensorMaterials

BeamCal:highenergydeposition fromlowenergeticpairsfrom beamstrahlung. Weperformdifferent characterizinglaboratory measurements(I7V,C7V,MIP response,lowdoseirradiation) aswellastestbeammeasurements.

≈ 5MGy/a

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MaterialsunderInvestigation

pCVD diamonds:

–

• +C55)/9

D – +//-' !ε>E5G + – +!%

GaAs:

– 7 / /! – /!! $% – +!CD%

SCCVDdiamonds:

– +!:% 8

CVD:ChemicalVaporDeposition

(courtesyofIAF)

polycrystalline CVDdiamond GaAs Singlecrystal CVDdiamond

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MiP ResponseofpCVD Diamond

typical spectrum ofanE6sensor

Sr90source Preamplifier Sensorbox Trigger box

• PA
• ;&
• Scint.

(4" (48

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CCDMeasurement

~ CCD CCD = Charge Collection Distance

= mean drift distance of the charge carriers = charge collection efficiency x thickness

ADC Channels ~ charge Counts

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InvestigationofSensors

polycrystalline CVDDiamond

response vs particle fluence response vs electric field Particles/10nsbunch

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HighDoseIrradiation

• IrradiationuptoseveralMGy:

10± 0.015MeV electronsandbeamcurrentsfrom10to 50nA (correspondingto60to300 kGy/h.)

• Keepingthesensorunderbiaspermanently.
• Thisisamuchhigherdoseratecomparedtothe

applicationattheILC(~1kGy/h) (1MGy =100Mrad isdepositedbyabout4x1015e7/cm2)

SuperconductingDArmstadt LINear ACcelerator Technical UniversityofDarmstadt

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TestBeamSetup

Beam Collimator Sensor Faraday cup

Beam current is measured using the Faradaycup. Together with correction factors from aGEANT4 simulation we determine the absorbed dosewith anerror ofless than 10%.

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IrradiationofPolycrystallineCVDDiamond

Afterabsorbing576MGy: CVDdiamondsstilloperational.

Verylowleakagecurrents(~pA) aftertheirradiation. Decreaseofthechargecollection distance. Generationoftrappingcenters duetoirradiation.

pumping decrease depumping by UV

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IrradiationofGaAs

CCDvs Dose IVbeforeandafterirradiation Increasebyabout2

Irradiatedoneindividualpadofeach prototypetoabout1– 1.5MGy.

Startingatabout50%of thesensorthickness. Ending atabout 3%

HV, [V]

• 600
• 400
• 200

200 400 600 A] µ I, [

• 2
• 1.5
• 1
• 0.5

0.5 1 1.5 2

After irradiation Before irradiation

Proc.ofthe IEEENSS07 inpreparation

40

• Front7endASICwill

contain32764dual gainchannels

• AnADCwillserve

~8(1?)front7end channels

• Firstprototypesin

AMS0.35Ym

LumiCalReadoutArchitecture

41

Physics mode

ASIC(fewchannels)submittedjune2007 Chargesensitiveamplifier+PZC+Shaper

Front7endDesign&Tests

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BeamCalElectronics

32channelsperchip Highoccupancy,alldataisreadoutat10bitsforscience purposes; Lowlatencyoutput,sumofallchannelsisreadoutafter eachbx at8bitsforbeamdiagnosis(fastfeedback) Prototypein0.187µmTSMCCMOStechnology

April2007: Highleveldesigncomplete July2007: Chargeamplifierdesigned October2007: Filterdesigned

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BeamCalElectronicsOperation

• Dual7gainfront7endelectronics:chargeamplifier,pulseshaperandT/Hcircuit
• SuccessiveapproximationADC,oneperchannel
• Digitalmemory,2820(10bits+parity)wordsperchannel
• Analogadditionof32channeloutputsforfastfeedback;low7latencyADC

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TimingandArchitecture

Needonemorelevelinthereadout architecturefortheinterfacetoFONT. Q:Howmuchcanbehandledbythe FONTsystemitself?

Readoutinrealtimeandwithlowlatency(~1s) Readoutbetweenbunchtrains

feedback proc.

FONT

~50signals

perlayerofBeamCal

GamCal

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Data Reduction

"58G 654.04 "56& 653.97 "56E 653.84 "58; 653.72 655 m σ9 85&8 71.65 85&" 71.65 85&F 71.87 85&" 71.72 0. m σ9 "85=6 85=8 σ 79.82 9.71

• digitized

;5G= 77.78 ;5F& 77.26 ""5E" 75.35 nm 9 85=8 10.18 85=8 10.18 85=8 10.18 10 1076m rad ε9 σ

• σ
• σ
• Nom

. Unit BP 32channels 16channels full details

Scenarios ofdata reduction for the reconstruction ofbeam parameters:

• use not alllayers (6thlayer)
• use 32/16channel clusters
• digitized information

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Summary

TheFCALCollaborationdevelopsthedetectorsin theveryforwardregionoftheILCindependentof adetectorconcept. MCsimulationsallowedtodevelopaveryclear understandingofthephysicsbackground,beam7 beameffectsandtherequirementsonpositioning andprecision. Precisionandpositionmonitoringisessentialfor theLumiCal.Radiationhardsensorsareofcrucial importancefortheBeamCal. BeamCalandGamCalareabletoprovidevaluable informationaboutthecollision.TheBeamCal electronicsisdesignedtoprovideafastfeedback signaltoFONT. WehaveanintensiveR&Dactivityonradiation hardsensors.WeinvestigateCVDdiamond,GaAs, SiC andstarttoinvestigateradiationhardSi.

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Backup

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TheChallengesforBeamCal

e+e7 pairsfrombeamstrahlungaredeflected intotheBeamCal 15000e+e7 perBX =>10– 20TeV totalenergydep. A"&4 / stronglydependenton thebeamandmagneticfieldconfiguration =>radiationhardsensors Detectthesignatureofsinglehighenergetic particlesontopofthebackground. =>highdynamicrange/linearity

e7 e+

Creationofbeamstrahlungatthe ILC

≈ 1MGy/a ≈ 5MGy/a e7 e7 γ e7 γ e+

e.g.Breit7Wheelerprocess

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GaAs afterIrradiation

3 2 1

GaAs 2 U=500V

1 2 3 4 5 6 7 8 9 10 11

A] µ current [ 1 1.2 1.4 1.6 1.8 2

ADC_Ch_0 Entries 10000 Mean 1725 RMS 471.5 1500 2000 2500 3000 3500 5 10 15 20 25 30 ADC_Ch_0 Entries 10000 Mean 1725 RMS 471.5

GaAs2_05-09-07_+200V_r6p5_003

0.00668556523 ± = 0.299694598

Gaus

α 0.994968653 ± = 1230.62683

pedestal

µ 0.79499805 ± = 34.5896301

pedestal

σ 1.7196908 ± = 28.54006

Landau

σ 1.31110656 ± = 1395.24866

Landau

MPV 3.20696712 ± = 32.1538811

Gaus

σ 0.00705631776 ± = 0.404671907

2nd Signal

β 3.40241218 ± = 70.8546143

Landau

σ 4.83202791 ± = 1965.77124

Landau

MPV 8.62905693 ± = 121.833336

Gaus

σ SUCCESSFUL

Partiallyirradiatedpadsshow twoverydistinctsignalpeaks. High:signalfromnotirradiatedarea Low:signalafter~1.5MGy

Leakagecurrentsincreaseby aboutafactorof2...butthistime itisintheArange.

50

• 10bitpipelineADC
• 1.5bitperstage
• Fullydifferentialarchitecture
• Pipelinestagessubmittedinjune2007

PipelineADCDesign

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BeamCalElectronicsOperation

Timingdiagram:betweenpulsetrains