1. Introduction Construction, Integration and commissioning on the surface Installation and commissioning after installation in the cavern Selected performance results from test-beams Some results from cosmics data analysis The ATLAS Liquid Argon Calorimeter: Construction, Integration, Commissioning Ph. Schwemling on behalf of the ATLAS LAr Group

3. The ATLAS Detector

4. The ATLAS Liquid Argon Calorimeters LAr Calorimeters: –EM Barrel : (|  |<1.475) [Pb-LAr] –EM End-caps : 1.4<|  |<3.2 [Pb-LAr] –Hadronic End-cap: 1.5<|  |<3.2 [Cu-LAr] –Forward Calorimeter: 3.2<|  |<4.9 [Cu,W-LAr] ~190K readout channels 46 m 13 m 4.5 m

5. The ATLAS Electromagnetic (EM) Calorimeter 2 wheels (16 modules) in the barrel and 1 wheel (8 modules) per endcap Accordion shape in EM barrel and end cap calorimeters (>22X 0 ) Main advantages –LAr as act. material inherently linear –Inherently radiation hard –Hermetic coverage (no cracks) –Longitudinal segmentation –High granularity (Cu etching) –Fast readout possible t drift =450 ns E

6. The ATLAS Forward and Hadronic Calorimeters FCAL1 Anode Structure FCAL End View LAr gap FCAl 1/2/3: 250/375/500 µm Forward Calorimeter (FCal) –3 wheels per endcap (10 ) Cu matrix for the first wheel (2.6, 28X 0 ) W matrix for the other two wheels (2x 3.7 ) Hadronic Endcap Calorimeter (HEC) –2 wheels per endcap (10 ), 32 modules each Cu absorbers (25mm/50mm thick) Each gap consists of 4 sub gaps of 1.85mm HEC module

7. Physics requirements Discovery potential of Higgs determines most of the performance requirements for the EM calorimetry Largest possible acceptance Large dynamic range : 20 MeV…2TeV (  3 gains, 12bits) Energy resolution (e ± γ):  E /E ~ 10%/√E  0.7% –  precise mechanics & electronics calibration (<0.25%)… Linearity : 0.1 % (W-mass precision measurement) –  presampler (correct for dead material), layer weighting, electronics calibration Particle id: e ± -jets, γ/π 0 (>3 for 50 GeV p t ) –  fine granularity Position and angular measurements: 50 mrad/√E –  Fine strips, lateral/longitudinal segmentation Hadronic – E t miss (for SUSY) –Almost full 4π acceptance (η<4.9) Jet resolution –  E /E ~ 50%/√E  3% η<3, –  E /E ~ 100%/√E  10% 3<η<5 Speed of response (signal peaking time ~40ns) to suppress pile-up Non-compensating calorimeter  granularity and longitudinal segmentation very important to apply software weighting techniques Jets Jets, Missing E t Electrons Photons

8. Construction HV and electrical tests after module assembly Repair of abnormal channels Mechanical measurements during production/assembly: Stability at 1% level Resulting constant term  0.5%

9. Integration Delivery of 3 cryostats and preparations of cryostats at CERN starts in 2002 Module production in institutes and delivery to CERN from 2001 – 2004 Wheel assembly in clean rooms from 2002 – 2004 Wheel insertion into cryostats from 2003 – 2004 Cold tests on the surface in 2004 – 2005 Barrel wheel inside cryostat Module construction in the labs

10. EM EndCap A wheel after its insertion, cabling finished, July 2004

13. Cold Commissioning on the Surface All three cryostats were commissioned at LAr temperatures (88K) filled with LAr on the surface (cold commissioning) The goal of the cold commissioning was to : –Check the connectivity and integrity of the connections and all the detector channels and calibration lines at LAr temperatures –Test the integrity of all HV channels at nominal voltage at LAr temperatures –Measure electronics parameters needed for signal reconstruction –Measure the noise and coherent noise (with ATLAS electronics boards) The barrel commissioning lasted 10 weeks in summer 2004 The end cap C commissioning lasted 8 weeks in winter 2005 The end cap A commissioning lasted 6 weeks in summer 2005 Number of channels to be tested on all three subdetectors: –190304 read out channels –14592 calibration lines –4248 HV channels

14. Cold Commissioning – Tests Applying High Voltage –Slow ramp up (measure current draw) –Stability test during several weeks HV continuity tests (EM and FCal only): –AC signal applied on the HV line –Via the detector capacity a signal is induced on the signal cables –Checks connectivity of the HV and signal lines To FE elec. Calib. signal R cal Pulsing all lines with the calibration board, and reading pulses back with the front end boards Reflectometry measurements LC, R cal measurements (EM) –Measure these parameters at cold –Used in the calibration run analysis Tests of the final Front- End-Crate electronics –Noise measurements Few (<1‰) abnormal channels 0.1-0.2 % amplitude stability over one month

15. Cold Commissioning Test Summary Signal & Calibration Bad channels (#|%) Bad calibration lines (#|acc.%) Dead channels (#|%) EMEC C40 | 0.131 | 0.046 | 0.02 HEC C3 | 0.11 3 | 0.373 | 0.11 FCal C10 | 0.700 | 0.00 EMEC A20 | 0.064 | 0.168 | 0.03 HEC A0 | 0.001/3 | 0.83 | 0.11 FCal A9 | 0.630 | 0.00 EM Barrel49 | 0.041 | 0.0131 | 0.03 HV Correction needed (HV#|acce ptance%) Dead (HV#|acce ptance%) EMEC C25 | 5.000 | 0.00 HEC C12 | 7.500 | 0.00 FCal C 8 | 1.800 | 0.00 EMEC A35 | 8.751 | 0.25 HEC A13 | 8.100 | 0.00 FCal A11 | 4.190 | 0.00 EM Barrel8.5 | 1.900 | 0.00 Situation in April 2006 > 99.7% of the detector channels work! » 99.9% of detector channels work! Since then, some of the HV problems repaired by « burning » shorts ECC had to be emptied. When refilling, changes may appear Final list of problematic channels being prepared now.

16. Commissioning After Installation As soon as the front end boards are installed in the cavern and connected to the ATLAS read out system regular calibration runs are recorded –Injection of a calibration pulse (via the R cal ) on the detector module inside the cryostat, and reading it back with the whole read-out chain –Allows to check the integrity of all connections, the status of the detector cells and the functioning of the read out chain and the calibration system Calibration pulse shapes for some FEB (one plot per front end board, each 128 channel) Amplitude (ADC counts) Time (ns) ADC Linearity of one calibration channel DAC counts (ADC-linear fit)/600 DAC counts Ramp run pulsing 3 barrel modules

17. Gaining practical experience : cryogenics Small temperature variations understood by cryo team.

18. Comparison of 3 runs (1 per month) Observe excellent stability of the maximum amplitude (calibration runs) and the baseline –Maximum amplitude stable to 0.14% –Pedestal variations below 0.05 ADC counts (<0.1MeV) Gaining practical experience : Read-out stability

19. Located at CERN, H8 (barrel) and H6 (end-cap) beam-lines. Electron beams from 10 to 300 GeV 4 Barrel modules (out of 32 total), 3 End-Cap modules (out of 16 total) tested between 2000 and 2002. Topics studied Position resolution, γ/π0 separation Response to muons Time resolution Uniformity, linearity, energy resolution Production testbeam

20. Calorimeter response to muons MiddleStrips

21. Time resolution of the LArg calorimeter E beam

24. Linearity for electrons E rec =λ(off+w 0 E 0 +E 1 +E 2 +w 3 E 3 ) 4 parameters,  dependant Simple method χ 2 = Σ(E i rec -E i true ) 2i2i 2

25. Resolution for electrons

27. End-cap combined testbeam 2004 Understand high  (2.5-4.9) region

28. Cosmic ray data

29. Cosmics commissioning goals Exercise Front-End electronics and readout chain Look for dead/bad cells Check/adjust detector timing at ns level Check cell response uniformity at 1-2% level

30. Commissioning with cosmics 1 2 3 4 A B 4 SD 8 trigger cables, more if LAr technicians Typically 15 k events over one week 2% events projective S/B about 10 in middle sampling Individual cell signal Projective muons energy deposit (middle sampling )

31. Predicted physic pulses vs data  Typical pulses with GeV energy deposit (same as for 5 samples)  Fair qualitative agreement in the peak and in the undershoot for every layer 25 samples E = 3.8 GeV Front, η ~ 0.23 FT7; Slot3; Ch72 Run 24606 Back, η ~ - 0.03 FT1; Slot9; Ch64 Run 24606 E = 17.0 GeV Middle, η ~ - 0.04 FT1; Slot11; Ch5 Run 24606 E = 6.3 GeV Predicted physics pulses vs data

32. Correlating LAr Time and Tile Time FEB: Side A (1), FT 23, Slot 12 Tile time is the time at the y = 0 crossing. A time-of-flight to the LAr cell correction is made. Slope consistent with 1 to ~5% with intercept values ~ 2ns. After fixing slope, intercept decreased to just under ~ 1ns. Correlating LAr time and Tile time

33. Spread of data about linear fit in previous slide represents combined LAr-Tile resolution. Width of T LAr - T Tile distribution quantifies the resolution. Resolution goes as the inverse of the energy - separate into bins of LAr cell energy. Fit to quadrature sum of E -1 term and constant term. Res agrees with test beam, Const substantially larger (TB, 0.65 ns).  to be understood Timing resolution with cosmics

34. Plot MPV of muon Landau distribution as a function of . Shape of various clustering methods agree well with MC and the expected cell depth at the ~2% level in 0.1  bins. The results use ~ 10k clusters. A naïve statistical extrapolation suggests ~160k clusters necessary to probe depth in cell  bins at 1% level. * All normalized to 0.3 <  < 0.4 bin Muon response dependance over 

35. Conclusions All LAr calorimeters successfully integrated in their cryostats and in ATLAS, after extensive test and quality control during construction. Excellent condition of the calorimeter (more than 99.9% of channels work), stability very good. Cosmic muons are routinely recorded together with the hadronic Tile calorimeter, muon detector and ID system. Data used to improve understanding of the detector and prepare real data taking The ATLAS calorimeter system will be ready in spring 2008 for the first physics data, expected in the second half of 2008 !

36. Spares

37. Calorimeters