1. ATLAS Liquid Argon Calorimeters Geneva Group Alain BLONDEL Arno STRAESSNER Ahmed ABDELALIM Daniel LA MARRA Eric PERRIN Gabriel PELLERITI Gilbert VIOLLAT Ibtesam BADHREES Irina SHREYBER Laurent ROSSELET Pierre BENE Sebastien PERNECKER 1 Journée de réflexion du DPNC Ahmed ABDELAIM 9/14/2007

2. 2 ATLAS LAr Calorimeters Electromagnetic Barrel (EMB) – 101760 readout channels Electromagnetic Endcap (EMEC ) – 62208 channels Presampler – (7808 barrel, 1536 endcaps) Hadronic Endcap (HEC) – 5632 channels Forward Calorimeter (FCal) – 3524 channels ~200,000 channels All with similar LAr signal pulse shapes. HEC FCal EMB EMEC Journée de réflexion du DPNC Ahmed ABDELAIM9/14/2007

3. LAr Detector Status  LAr barrel and endcap calorimeters installed in ATLAS cavern and cooled down  All high-voltage channels connected and can be powered  Commissioning ongoing  calibration, noise, cross-talk,...  cosmic data taking  Read-out electronics  installation complete  now in retrofit phase to fix last problems  Successful DAQ test run beginning of September:  LAr was the only system to reach 40 kHz data taking rate Journée de réflexion du DPNC Ahmed ABDELAIM 39/14/2007

4. Geneva ROD Group Activities(1)  ROD = Read-Out Driver  ROD production is completed;  252 ROD boards produced = 38 for Tile Calorimeter + 214 for LAr Calorimeters  192 LAr RODs are installed in ATLAS counting room  ROD installation finished;  VME crates, ROD boards, ROD cooling system  Many problems solved with the help of engineers and technicians: For example: leaks in cooling system Journée de réflexion du DPNC Ahmed ABDELAIM 49/14/2007

5. Geneva ROD Group Activities(2)  Current ROD activities:  Repairing last boards from production → additional spares  Repair boards that return from ATLAS → mainly failures of minor components  Recent problem: retrofit all ROD boards with big capacitor to stabilize power consumption Slow control software for ROD system well advanced  control and monitoring of VME crate power and voltages ROD cooling system 5Journée de réflexion du DPNC Ahmed ABDELAIM9/14/2007

6. 6 ROD Functionality Signal: triangular shape, amplified&shaped Sampled every 25ns (“samples”) Typically 5 samples used for energy reconstruction (up to 32 samples for calib) E, time ,  2 extracted from weighted sum of samples: Optimal Filtering (OF) Pedestal, noise autocorrelation function, and signal shape are all input to the energy reconstruction. Detector pulse Shaped and sampled signal Time (ns) Sample amplitude #Samples N Normalized pulse shape & its derivative pedestal Journée de réflexion du DPNC Ahmed ABDELAIM9/14/2007

7. 7 Crosstalk between channels: EMB Crosstalk affects the LAr waveform Look at signal in neighboring cells when a particular cell is pulsed Several definitions to quantify crosstalk. Use: Max Amp of neighbor Max Amplitude of pulsed channel Pulsed Neighbor (x50) Long distance (x50) LAr EM Barrel (%) Calib. Run 8045 TB (Aug’ 99 or Oct’01) Capacitive Strip-strip (neighbors) 7.17 Strip-strip (next- to-neighbors) 0.810.88 ResistiveMiddle-strip Electrode A/B 0.070/ 0.085* 0.06/ 0.09* Inductive Middle-middle 1.271.4 Middle-back 0.890.7 Back-back 1.491.7 * Correction estimated for long distance crosstalk Journée de réflexion du DPNC Ahmed ABDELAIM Back Middle Strip 9/14/2007

8. 8 Timing studies: 2006 cosmics Look at offset as a function of FEB for each FT FEB offsets would include: – Differences in cable length – Extra cables for triggering – Other electronics offsets Note: offset is relative to Tile time (which is also being optimized) Run 2060 FT C side FT A side Journée de réflexion du DPNC Ahmed ABDELAIM Run20720 Event16779032 9/14/2007

9. 9 Energy reconstruction: 2006 cosmics Impact of # of samples on energy reconstruction biases – Use CaliWave+wave parameters from warm/cold measurements+Response Transformation Method (RTM) to predict physics pulse – Poor physics prediction wave in undershoot area creates bias. Look at # samples used: FromToEnergy Bias (%) 57+1.4 712+0.9 1215-0.2 1520-0.5 2029+2.0 5S15S 20S29S tt tt Journée de réflexion du DPNC Ahmed ABDELAIM 9/14/2007

10. Summary and Outlook LAr calorimeters in good shape ROD production and installation is finished system maintenance is ongoing: – ROD board repairs – testbench maintenance – slow-control of the ROD system calibration data provide a good understanding of – The quality of the LAr wave – Calibration coefficients Cosmics data provide an understanding of timing, uniformity, and energy reconstruction of the ATLAS calorimeters everybody is cordially invited to celibrate with us the END OF ROD-PRODUCTION with a drink at University on Thursday September 20 th, at 12h30 10 Journée de réflexion du DPNC Ahmed ABDELAIM 9/14/2007