TheupgradeoftheCMSECALBarrelCalorimeter

attheHL-LHC

ChiaraRovelli–INFNRomaOnbehalfoftheCMSCollaboraBon

ICHEP2018,SeoulJuly5th

TheCMSElectromagneBcCalorimeter

2

Homogeneous,compact,hermeBcPbWO4crystalscalorimeter

+Lead/SiPreshower

coverage crystals/strips readout

Barrel(EB) |η|<1.48 61200 APD

Endcaps(EE) 1.48<|η|<3 14648 VPT

Preshower 1.65<|η|<2.6 137216

BarrelPreshower

Endcap

S/(S

+B) W

eight

ed E

vent

s / G

eV

0

2000

4000

6000

8000

10000

12000

14000

DataS+B fitB component

σ1 ±σ2 ±

S/(S+B) weightedAll categories=1.16µ=125.4 GeV, Hm

--

Preliminary CMS TeV) (13-1 35.9 fbγγ→H

(GeV)γγm100 110 120 130 140 150 160 170 180

200−

0

200400

600 B component subtracted

Currentdesigndrivenbyenergyperformancerequirements

•  ECALcrucialfortheHiggsbosondiscovery•  Keycomponentformanysearchesfornewphysicsandprecisionmeasurements

Hadronirradia7onofcrystals=>•  Lossoflightoutput(LO)•  Degrada9onofenergyresolu9on

Barrel:•  ~50%lightaaer~3000/b•  RelaBvelysmallenergyresoluBondegradaBon•  SamePbWO+APDtechnology

Endcaps(+HCALEndcaps)•  WillbereplacedbyHGCAL

HL-LHCandECALcrystals

3

Inst.Lumi(cm-2s-1) Peakpileup(PU) Int.Lumi(b-1/y) Hadronfluence(parBcles/cm2)

LHC 1.7x1034 60 40-50 12x1011(|η|=1),3x1013(|η|=2.6)

HL-LHC 5-7.5x1034 140-200 250-320 7.6x1012(|η|=1),2x1014(|η|=2.6)

HL-LHCgoal:x10integratedluminosityLargeincreaseinpileupandintegrateddosewrtLHC

InducedabsorpBoncoefficient

EBupgrade:triggerImprovedLevel-1trigger(L1)capabili=esneededatHL-LHC•  toexploitlargerLHCluminosity•  toimplementL1track-trigger

Largertriggerratesandtriggerlatenciesmandatory•  RequirereplacementofECALelectronics

Improvedrejec7onofECALdirectAPDsignalsrequired•  “spikes”,akalargesignalsduetohadroninteracBonswiththeAPD•  isolated&fasterthanscinBllaBon

WilldominateL1rateatHL-LHCotherwise•  Mi7ga7onneededinnewelectronics

ECALdeposits(scinBllaBon+spikes),<PU>=200

4

LHCtotalL1bandwidth

HL-LHCtotalL1bandwidth

APDperformanceAPDswillexperienceincreasedleakagecurrentsduetoLHCirradiaBon

Increaseinnoise(x10)willsignificantlydegradetheresoluBonMiBgaBonmandatory:•  Barrelcooling:18°->6–9°•  Newfront-endpre-amplifier(newVFE):shorterpulseshaping

•  alsosmallerPUimpactandbeqerS/N

5

MiBgaBonmandatory:•  Barrelcooling:18°C->9°C–6°C•  Newfront-endpre-amplifier:shorterpulseshaping

Maintainingreconstruc9onperformanceathigh(200!!)pileupisachallenge

Eg:H->γγReducedprimaryvertexidenBficaBonefficiency(fromrecoilingtracks)•  80%now->30%HL-LHC•  Affectsanalysissensi9vityPileupverBcesspreadalongzand=me:Precision7mingforchargedandneutralspar7cleskeytoreducePUcontamina7onEg:H->γγECAL+trackprecisionBming(30ps)=>~currentvertexlocalizaBonefficiencyatPU=200

ManyphysicschannelscanbenefitfromECALprecision9ming•  Eg:BSMlong-livedparBcleswithdelayedphotonsinthefinalstate

PrecisionBming

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(SeeA.Benaglia’stalkonCMSdedicated=mingdetector)

EBupgradehighlights

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Staythesame:crystals+APDs

New:on-detectorelectronics(VFE+FE)•  Toimprovespikes/PU/noisemiBgaBon•  Toexploreprecise(~30ps)Bmemeasurement

New:off-detectorelectronics•  TocopewithhigherbandwidthfromFE

New:operatecolder(9°C-6°C)•  TomiBgateAPDnoise

ReplacementofalldetectorservicesduringCERNLS3•  LV/HVlines,readoutandcontrollinks•  Newcoolingsystem+improvedpipesinsulaBon

replace

keep

Upgradeneededtomaintainexcellentperformance!

VFE:choiceandR&Dprogress

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NewVFEboardswithre-designedASICs•  Pre-amplifier:TransImpedanceAmplifier(TIA)architecture

•  Twogainranges(G1,G10),2TeVdynamicrange•  ADC:customchip,withcommercialcoreanddatacompressionsystem

•  12bit,160MHzsampling

MeetphysicsrequirementsofHL-LHCop7mizingshaping7meandsamplingrate•  noiseandPUmi=ga=on,precision=ming ]σNormalized Amplitude [A/

0 200 400 600

Reso

lution

[ps]

0

20

40

60

80

100

120

ps2 0.9)x10±N: (61.7 0.9 ps±C: 17.9

ps2 0.9)x10±N: (61.7 0.9 ps±C: 17.9

ps2 0.9)x10±N: (61.7 0.9 ps±C: 17.9 ps2 0.9)x10±N: (61.7

0.9 ps±C: 17.9

5GS/s160MS/s80MS/s, edge sampling80MS/s, top sampling

C⊕ σA/

N

CMS Preliminary ECAL Test Beam 2016

TIAprototypetestedinrecenttestbeams

•  NoiseperformancematchesexpectaBons

•  30psBmingresoluBonachievedattestbeam•  At25GeVatHL-LHCstart•  At60GeVatHL-LHCend

With160MHzsampling

30ps

NoisecontribuBontoBmeresoluBon

FE:choiceandR&Dprogress

9

FEcards:transferallcrystaldataoff-detectorTriggerprimiBvegeneraBonoff-detector=>nolatencybuffer/pipelineHighspeedopBcallinks:CERNGigaBitTransceiver(GBT)+chipset•  Allowsfull-granularityreadoutfortrigger•  Datarates:~30GB/sper25channelswithdatacompression

FEdemonstratorequippedwithGBTchips

beingtestedwithlegacyVFEandPhase1triggerboardsinCERNtestbeams

EBupgradeimpactontrigger

10

Newelectronics->improvedinforma7ontoLevel-1trigger

Shorterpulseshaping•  MainhandleforspikesdiscriminaBon

FullgranularityatL1(1x1crystal,vscurrent5x5)•  Advancedclusteringalgorithms,alsomatchingtoL1-tracks•  EventtopologyasbackupforspikesdiscriminaBon

upgrade

40MHz

5GHz

Spike-killingalgorithmbasedonpulseshapeperformingverywell

forET>5GeV

Summary

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ECALperformancecrucialforCMSphysicsduringLHCRun1andRun2ECALbarrelupgradeneededtomaintaingreatperformanceduringHL-LHC•  GoodnoiseandpileupmiBgaBon(9°C-6°C)•  PreciseBmeinformaBon(30ps)•  GoodtriggercapabiliBes(rates,latenciesandspikesrejecBon)BasicarchitecturedefinedanddocumentedintheTDR,publishedlastyear•  CERN_LHCC_2017_011;CMS_TDR_015PrototypesundertestsatCERNSPSECALbarrelupgradeplannedduringLHCLongShutdown3UpgradedECALbarreldetectorwills=llbeakeypartofCMSduringHL-LHC

Backup

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Designchoices

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Pre-amplifier:TransImpedanceAmplifier(TIA)architecture•  Twogainranges(G1,G10).2TeVdynamicrange,with50MeVLSB•  ADC:customchip,withcommercialcoreanddatacompressionsystem•  12bit,160MHzsampling.DualchannelwithgainselecBonlogic•  Datatransferunit(DTU)implementsdatacompressionbeforeFE

FE:transfercrystaldataoff-detectorusinghigh-speedopBcallinks•  lpGBT(4x10.24Gb/sdatalinks,1x2.56Gb/scontrollink)•  eLinkserialinterfacetoADC,clockandslowcontrol

Lowvoltageregulator(LVR,oneevery5x5crystals)•  Neededvoltages(1.2Vand2.5V)suppliedbypoint-of-loadFEASTDC/DCconverters

LossinenergyresoluBon

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SpikesrejecBon

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PulseshapediscriminantEventtopologydiscriminant