The ATLAS Tile Calorimeter:Commissioning and Preparation for Collisions

Presented by Oleg Solovyanov On behalf of the Tile Calorimeter Collaboration of ATLAS experiment

Other talks about Tile Calorimeter:ATLAS Tile Calorimeter performance for single particles in beam tests, T.DavidekThe response of ATLAS Tile Calorimeter to pions and protons, M.SimonyanMC Comparison in the ATLAS Combined test-beam, P.Speckmayer

CommissioningCalibration systemsCosmicsPreparation for collisions

XIII International Conferenceon Calorimetry

in High Energy Physics

CALOR 2006Pavia, Italy

Tile Calorimeter

Barrel part (<1.7) of the ATLAS Hadron CalorimeterSampling calorimeter: iron/scintillating tiles (perpendicular to beam axis)Double PMT readout via WLS fibersTile readout is grouped into projective geometry cells10K readout channels in 256 electronics “drawers”, data sent over fiber linksAnalog trigger sums from projective towers to L1 trigger system

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Status at CALOR 2006:

Barrel at final position Z=0Ext.Barrels completeServices being connectedFinal power supplies are comingStandalone FE commissioning

Still to do in 2006-2008:Finish servicesInstall power suppliesFinish FE commissioningCalibration systemsIntegration within ATLASCosmic runsMore...

Today’s status. Services

All the services have been connected&testedCoolingPowerTriggerReadout

Auxiliary fibers connection

Connection aux.fiber-Patch Panel

Drawer Connection

Interface board connection inside drawer (End of Fiber)

USA15-UX15 fiber

Special tests for optical fibers: Attenuation test:

LED source & meter at 2 frequencies 1300, 850 nm with maximum acceptable loss of 3dB

OTDR: Optical Time Domain Reflectometer Analyses the loss in an optical fiber by: Injecting short laser pulses into it Counting the backscattering and reflection

photons as a function of time. The idea is to locate with a precision of few

centimeters any break or splice loss Length of fibers can be measured (used for

trigger delays) 12 fibers of barrel (out of 512) had to be

respliced (~2%) Tests done for trigger, readout, and laser fibers

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In-situ certification with mobile readout unit

Online commissioning - final backend - real-time: fast response - low statistics

Offline commissioning - final TDAQ system - athena reconstruction - high precision - data integrity studies - calibration constants

FE electronics commissioning

Comissioning steps:Comissioning steps:

Pedestals: noise

Charge injection: electronics calibration digitizers

LED(Laser): PMTs, HV system

Cosmics: Tiles+PMT+readout

Data types:Data types:

I.Korolkov CALOR2006 – FE commissioning details

Tools

5

FE electronics long-term stability

Pedestals: high-frequency noise (pedestals, cosmic runs) - stablity of noise: variation in 4 months: < 0.1 ADC counts - stability in b-field: variation ON-OFF: < 0.1 ADC counts

Calibration constants (CIS data): - digitizer readout chain: RMS in 3 months: < 0.1% - integrator readout chain: RMS in 15 months: <0.1%

PMT gains (LED data) - stability in variying B-field: variation ON-OFF < 0.1%

Stability of PMT gain in B-field: variation ON-OFF < 0.1%

Stability of electronics calibration constant (3 months): Relative variation of calibration constant: < 0.1 %

Integrator gain stability (15 months) Relative variation for 20 modules < 0.1%

Module number Module number

low gain

high gain

RM

S/M

ean

LBA52

Vari

ati

on/M

ean

Summary: long-term stability < 0.1%

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April 2007 – Extended barrel ready to move inside7

February 2008 – Extended Barrels moved in8

May 2008 – calorimeters closed and ready in final position 9

Detector control system (DCS)

DCS system is fully operational All FE modules are powered HV is on Monitoring tools are provided Operating parameters are stableCALOR 2006, 26-30 May, Pavia O.Solovyanov IHEP

10

Data Acquisition System (DAQ)

106 hours of continous cosmic running!

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Data Quality Monitoring

Channel based monitoring, pedestals and samples

Physics quality, timing, occupancy

Automated histogram/plots checks

Monitoring at all levels of with appropriate focus

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Mixer

Tile

Fibre

PMT

Divider

3-in-1

Analog

Digital

Optical Interface

IntegratorADC-I Adder

Digitizer

Physics events

Minimum Bias

Cesium

Laser

Charge Injection

ROD

HVOpto

HVMicro

Canbus

Canbus

HV

Energyµ

TriggerHad

Trigger

DC Calibrations,Luminosity Monitoring

Mother Board

PMT Block

TileCal cell

L H

Drawer

TTC

Calibration Systems

Laser calibration system

Laser calibration system is fully installedCommissioning is well under wayLaser runs are taken routinelyAllows timing equalisation

An adjustment of fibers has been doneMore narrow amplitude spread achieved

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First Cesium scans of installed modules in the pit

Cesium calibration system is working3 Cs137 sources installed to calibrate all systemsFirst runs performed in all modules, 8 hours per runNo serious problems have been foundHV setup and tuning is under wayTests with full magnetic field until JulyAim to calibrate all 10K channels at em scale ~2%

PMT response to passing source

L1 Calo tests

CosmicsD.Prieur

L1 calorimetry trigger is taking shape:

Mapping tests using CIS pulses

Timing tests using Laser

Energy calibration using CIS

Energy calibration using cosmics

Calibration with cosmic muonsTime distribution of cosmic signals

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Integration milestone weeks

Starting from the end of 2006 a number of integration weeks was organized Move from standalone detector commissioning to the combined one Collect cosmic data, with different trigger sources Perform calibrations, timing and trigger setup Train shifters, multiply experts, enhance monitoring tools and documentation Prepare for beam!

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M1 – 2006-12

M2 – 2007-02

M3 – 2007-06

M4 – 2007-08

M5 – 2007-10

M6 – 2008-02

M7 – 2008-05

Beam!

Cosmic muon event in extended barrel triggered by L1Calo

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Cosmic muon event in the TileCal barrel

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3D display of cosmic muon event in TileCal

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Another 3D event in Tile

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Fake Missing ET From Cosmic Rays

Events with 4 TeV MET?

Events with > 200 GeV MET, rate: ~ few/day

2007 data runs 15923 to 17020, bad channels removed, Ecell>400MeV, MET@cell level, em scale

04/21/23 LAr Commissioning 23

Air shower, good pulse shapesET miss (TileCal) = 130 GeV

Δt = -16 ns

04/21/23 LAr Commissioning 24

Hard bremsstrahlungET miss (TileCal) = 1.2 TeV

Good signal pulse shapesIn TileCal (& LAr)

Δt = -16 ns

04/21/23 LAr Commissioning 25

Hard bremsstrahlungETmiss = 4 TeVTileCal 10-bit ADC saturated (1023)

Signal reconstruction assigns large error to saturated samples, fits remaining samples(tested in high/low gain)

Also neighbouring cells with normal pulse shapes, including 1 cell with 200 GeV. Energy loss in just 1 scintillator tile less likely.Highest energy event recorded in ATLAS? Δt = -30 ns

Background Rejection via

Calorimeter Timing

04/21/23 26

Transit time from top to bottom of

Calorimeter (~ 6m)

~ 18 -19 ns

Jets MC

Cosmics MC

ATLASCosmicData2007

Muons on top: t<0

Muons on bottom: t>0

IP

Jet: t=0

Jet: t=0

Timing resolution order 1 ns

Rejection via Electromagnetic Fraction in Data

04/21/23Note: not quite a fair data/MC comparison as clustering not applied to data.Rather meant to indicate a cut which can be applied to reject background.

LAr Commissioning

Saturated PMT and surrounding cells

1.13 GeV

2496.36 GeV

0.58 GeV0.43 GeV

2.87 GeV

0.79 GeV

Conclusions

ATLAS Tile Calorimeter is fully installed and powered with all the necessary servicesAll FE and BE electronics have been thoroughly commissioned to arrive to the first collisions with minimal number of bad channels (<1%)DCS and DAQ systems are running in full swingA massive number of sofware and hardware tools have been developed during commissioning and used to ensure good performanceA good set of monitoring tools are ready to monitor the performance of the detectorAll calibrations systems are installed and working to provide well-calibrated detector for the first beamsTile Calorimeter is fully integrated with other ATLAS subsystems, including L1 triggerLarge data sets of cosmics data have been acquired and being studiedAn impressive number of experts and shifters are prepared for ATLAS running

Waiting for collisions!

Backup slides

M5 cosmics, triggered by muon chambers

Bottom

Top

M3 cosmics, energy deposited in TileCal, triggered by Tile

IPP Canada April 2005 Richard Teuscher 33

Examples of beam-halo muons in ATLAS

A typical snake …

Total rate 105 kHz E > 10 GeV 16 kHzE > 100 GeV 1 kHzE > 1 TeV 10 Hz

L=1034

Muons at cavern entrance