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Drift Time Measurement in the ATLAS Liquid Argon Electromagnetic Calorimeter using Cosmic Muons

Editors : C. Collard, C. Gabaldon & D. Fournier

Published in EPJC

Status : accepted by EPJC

arXiv:1002.4189

Figures

  • Figure 1: Accordion structure of the barrel. The top figure is a view of a small sector of the barrel calorimeter in a plane transverse to the LHC beams. Honeycomb spacers, in the liquid argon gap, position the electrodes between the lead absorber plates.
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/larg_principe.gifFig1 - Accordion Structure eps file

  • Figure 2: Typical single ionization pulse in a cell of layer 2 of the barrel (left) and endcap (right) of the calorimeter. The large red dots show the data samples, the small blue dots the prediction and the grey triangles the relative difference (data (S) - prediction (g))/S_max, on the scale shown on the right side of the plot (normalized to the data).
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/pulse_barrel.gifFig2 Left - Ionization pulse in EMB eps file https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/pulse_endcap.gifFig2 Right - Ionization pulse in EMEC eps file

  • Figure 3: Nominal HV (black dots) and nominal gap width w_gap (blue triangles) versus eta in the 2nd layer of the EM calorimeter.
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/HVvsEta.gifFig3 - HV and gap width vs Eta eps file

  • Figure 4: Schematic view of a LAr gap. The nominal position of the readout electrode (dashed line) is exactly equidistant from the lead absorbers. Any shift with respect to the nominal position (solid line) causes an increase of the gap width on one side of the electrode, and a decrease on the other side.
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/ElectrodeShift.gifFig4 - LAr gap eps file

  • Figure 5: Current as a function of time for a perfect centering of the electrode (delta_gap=0 \mu m), a shift of delta_gap=100 \mu m and delta_gap=200 \mu m.
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/current.gifFig5 - Current vs time eps file

  • Figure 6: Monte Carlo simulation for (left) T_drift and (right) T_bend versus eta for the three endcap layers: layer 1 (red triangles), layer 2 (black dots) and layer 3 (blue squares).
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/TDriftvsEta_MC_EMEC.gifFig6 Left - T_drift vs eta eps file https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/TDriftvsEta_MCbend_EMEC.gifFig6 Right - T_bend vs eta eps file

  • Figure 7: (left) Q^2_0 versus S_max^gain and (right) Q^2 versus S_max in layer 2 of the barrel. The black points correspond to the mean value.
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/chi2.gifFig7 Left - Q^2 vs S_max eps file https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/chi2star.gifFig7 Right - Q^2_0 vs S+max^gain eps file

  • Figure 8: Absolute value of the shift parameter as a function of the drift time in the barrel (left) and in the endcap (right), for layer 2.
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/ShiftvsTdrift_EMB_Middle.gifFig8 Left - Shift vs T_drift in EMB eps file https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/ShiftvsTdrift_EMEC_Middle.gifFig8 Right - Shift vs T_drift in EMEC eps file

  • Figure 9: Distribution of the absolute value of the shift parameter in layer 2 of the barrel (left) and endcap (right).
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/Shift_Middle_barrel.gifFig9 Left - Shift in EMB eps file https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/Shift_Middle_endcap.gifFig9 Right - Shift in EMEC eps file

  • Figure 10: Drift time as a function of eta in layer 2 of the barrel: using the RTM method (open dots), the FPM method (red triangles) and the prediction described in the text (purple line).
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/TDriftvsEta_EMB_Middle.gifFig10 - Drift time vs eta in barrel layer 2 eps file

  • Figure 11: Drift time as a function of phi in layer 2 of the barrel: using the RTM method (open dots), the FPM method (red triangles) and the prediction described in the text (purple line)
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/TDriftvsPhi_EMB_Middle.gifFig11 - Drift time vs phi in barrel layer 2 eps file

  • Figure 12: 2D map of T_drift in (eta,phi) for layer 3. The empty bins correspond to sectors with non nominal HV.
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/MapEtaPhi_TDrift_EMB_Back.gifFig12 - 2D map for Drift time in eta,phi in barrel layer 3 eps file

  • Figure 13: Drift time as a function of eta in layer 1 of the barrel: using the RTM method (open dots) and the FPM method (red triangles).
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/TDriftvsEta_EMB_Front.gifFig13 - Drift time vs eta in barrel layer 1 eps file

  • Figure 14: Drift time as a function of eta in the presampler barrel using the FPM method (red triangles). The full purple line represents the prediction normalized to the region 0.8<|eta|<1.2, using Equation 15 and the gap values given in Table 5. The empty bins correspond to sectors with non nominal HV.
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/TDriftvsEta_EMB_Presampler.gifFig14 - Drift time vs eta in barrel layer 0 eps file

  • Figure 15: Drift time uniformity between groups of 4x4 cells (Delta eta x Delta phi = 0.1x0.1) for barrel layer 2.
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/UniTdrift_barrel.gifFig15 - Drift time uniformity in barrel layer 2 eps file

  • Figure 16: (eta,phi) map in which |delta_gap| is plotted per bin of 0.1x0.1
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/MapEtaPhi_Shift_EMB_Middle.gifFig16 - 2D map for Shift in eta,phi in barrel layer 2 eps file

  • Figure 17: Drift time versus pseudorapidity for layer 1 (left), layer 2 (middle), and layer 3 (right) cells of the endcap. Black points are the data and red triangles Monte Carlo predictions for photons. The vertical dashed lines show the boundaries between different high voltage regions.
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/TDriftvsEta_EMEC_Front.gifFig17 Left - Drift time vs eta in layer 1 of endcap eps file https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/TDriftvsEta_EMEC_Middle.gifFig17 Middle - Drift time vs eta in layer 2 of endcap eps file https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/TDriftvsEta_EMEC_Back.gifFig17 Right - Drift time vs eta in layer 3 of endcap eps file

  • Figure 18: Drift time versus pseudorapidity for the three layers of the endcap: layer 1 (red triangles), layer 2 (black dots), layer 3 (blue squares). The vertical dashed lines show the boundaries between different high voltage regions.
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/TDriftvsEta_EMEC.gifFig18 - Drift time vs eta in layer 1,2,3 of endcap eps file

  • Figure 19: Drift time normalized to the average value versus phi for layer 2 of the eta>0 (left) and eta<0 (right) endcap wheels. The black dots are the average per phi bin and the vertical dashed lines show the boundaries between different modules.
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/TDriftvsPhi_EMEC_Middle_A.gifFig19 Left - Drift time vs Phi in layer 2 of endcapA eps file https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/TDriftvsPhi_EMEC_Middle_C.gifFig19 Right - Drift time vs Phi in layer 2 of endcapC eps file

  • Figure 20: Drift time uniformity between groups of 4x4 cells (Delta eta x Delta phi = 0.1x0.1) for endcap layer 2. The normalization is obtained as a fit to the data using a first order polynomial in each HV region to cancel out the influence of the gap variation with eta.
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/UniTdrift_endcap.gifFig20 - Drift time uniformity in endcap layer 2 eps file

  • Figure 21: Electrode shift as function of phi for layer 2 of the endcap. The black dots are the average per phi bin and the vertical dashed lines show the boundaries between different modules.
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/ShiftvsPhi_EMEC_Middle.gifFig21 - Shift vs phi in endcap layer 2 eps file

  • Figure 22: (left) Drift time and (right) Drift velocity (at E = 1 kV/mm) versus eta in layer 2. The black dots are the average per eta bin.
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/TdriftvsEta_S2_EMCoverage.gifFig22 Left - Drift time vs eta in layer 2 eps file https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/VdriftvsEta_S2_EMCoverage.gifFig22 Right - Drift velocity vs eta in layer 2 eps file

  • Figure 23: Drift velocity distribution for the barrel (left) and endcap (right).
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/VDrift_EMB.gifFig23 Left - Drift velocity for barrel eps file https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/VDrift_EMEC.gifFig23 Right - Drift velocity for endcap eps file

  • Figure 24: Relative difference between the design gap values and the values extracted from T_drift measurements.
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/Diff_gapvsEta.gifFig24 - Difference of gap values vs eta eps file

  • Figure 25: Drift velocity versus eta in the layer 2 at the operating point extracted from T_drift measurements.
https://twiki.cern.ch/twiki/pub/AtlasPublic/LArPaperDriftTime/VdriftvsEta_op.gifFig24 - Extracted Drift velocity versus eta in the layer 2 at the operating point eps file


Responsible: IsaWingerter

-- CarolineCollard - 15-Jul-2010

Last reviewed by: Never reviewed

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Topic revision: r7 - 2010-12-06 - PatrickJussel
 
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