MDT Performance with 2012 Collision Data Content of the CONF-NOTE

1. MDT Performance with 2012 Collision Data Content of the CONF-NOTE Mauro Iodice Muon Week – Muon Performance Meeting, May15th, 2013

2. Introduction • Writing/Finalizing THREE CONF-NOTES is one of the short term objectives of the Muon Analysis Task Force (MATF) Working group: • -- Alignment CONF-NOTE (main results presented in several talks by Pierre-Francoise) • -- MDT Calibrations CONF-NOTE (previous talk by Mike/Ed) • -- MDT Performance with collision data CONF-NOTE, mainly focusing on: • Resolution • Efficiencies • Dependence with background hit rates In the following: -- list of content and main results for the MDT Performance CONF-Note Most of the material from recent analyses by Xin Fang MANY THANKS ! Mauro Iodice – Muon Week – Performance Meeting, May15th, 2013

3. MDT Performance Conf Note – Proposed List of Content • MDT tube hit rate Vs Luminosity • -- Tube average hit rates per chamberVs Luminosity • -- Saturationeffectsat high rates??? (seeP.FleischmannMuon Week March 26th) • MDT Resolution Vs DriftRadius • -- Tube hit Residuals: Establishfitting procedure • -- Resolution: Definition and methods • -- Resolutionmeasurement for differenttypes of chambers • -- Comparisonamongdifferentmethods • -- Comparison of results with differenttrackpTselection: checkresults with curvedsegmentsfitsatlowpT • -- Dependence with tube hit rates • Efficiencies • -- Definition (Hardware efficiency / segmentreconstructionefficiency) • -- EfficienciesVs radius for differenttypes of chambers • -- Dependence with tube hit rate • Comparison with simulation (ifavailable/feasible) • startingproject on possibleagingeffects of MDT tubes Vs Integratedluminosity from MDT chargeresponse (ADC) of the tubes Vs time (and Vs position, i.e. occupancy Mauro Iodice – Muon Week – Performance Meeting, May15th, 2013

4. For <L> ~ 3.8 1033 cm-2s-1 MDT Hit Rates (Hz/tube) Highest rates on EIL1 chambers 37.5 KHz/tube TDC BarrelA TDC EndcapA Compute average tube hit rate per chamber counting “out of time” hits in TDC spectra per chamber (and divide by num. tubes) Hz/tube • <LUMINOSITY> ~ 3.8 1033 cm-2s-1 Mauro Iodice – Muon Week – Performance Meeting, May15th, 2013

5. MDT Hit RatesNormalized to Unit area (Hz/cm2) Average rate per tube per chamber normalized to average tube length x 3cm Hz/cm2 Highest rates on EIL/S chambers ~ 44 Hz/cm2 • <LUMINOSITY> ~ 3.8 1033 cm-2s-1 Mauro Iodice – Muon Week – Performance Meeting, May15th, 2013

6. MDT Resolution Vs DriftRadius MDT Resolution can be obtained by straighttrackfitting (segment) from “residualwidths” s(r) and extrapolationerrors: Can also be obtained by the geometricmean of biased and unbiasedhit “residualwidths” ( NIM A538 (2005) 372-383 ) • Residualdistribution  establishfittingfunction • Define “residualwidth” Mauro Iodice – Muon Week – Performance Meeting, May15th, 2013

7. MDT Resolution – Fitting of Residuals • Non gaussian shape close to the wire • Fit at different radii with Double Gaussian • (small contribution from non-core gaussian for r>2mm) • Residual Width = weighted average of large and narrow gaussians widths: Resolution estimate insensitive to Systematic offset Mauro Iodice – Muon Week – Performance Meeting, May15th, 2013

8. MDT Resolution – Results Barrel A Barrel C Endcap A Endcap C Mauro Iodice – Muon Week – Performance Meeting, May15th, 2013

9. MDT Resolution – Results Providedweaccept the fitting procedure and methods, thisisnow an establishedresults. Many cross-checksperformed(can be reported in the CONF-NOTE) Allresults are consitent • Comparison with H8 Test-Beam data – CAVEAT: • Test Beam data takenatfixedangles – betterknowledge of extrapolationerror • Test-Beamresultsobtained with differentresidualfitting procedure • ATLAS Collision data include slewingcorrections (notincluded in TB) Mauro Iodice – Muon Week – Performance Meeting, May15th, 2013

10. MDT Resolution– Dependence on Hit Rate • The data-sample was analysed in separate “regions” with increasing luminosities • Resolutions for the EIL1 chambers have been estimated (next slides) Mauro Iodice – Muon Week – Performance Meeting, May15th, 2013

11. EIL1Resolution – Results @ differentLuminosities • Region A • <L> ~ 51033 cm-2s-1 • Region B • <L> ~ 4 1033 cm-2s-1 REGION A • Region C • <L> ~ 3 1033 cm-2s-1 • Region D • <L> ~ 21033 cm-2s-1 NO EVIDENCE OF RESOLUTION DEGRADATION UP TO 5 1033cm-2s-1 (~55 Hz/cm2) Mauro Iodice – Muon Week – Performance Meeting, May15th, 2013

12. ResolutionDegradation for High Rates …asexpected from Test-Beam under high background rates By S.ZIMMERMANN March 2004 (GIF) Mauro Iodice – Muon Week – Performance Meeting, May15th, 2013

13. MDT TUBE EFFICIENCY • Definition, method, results in “low background rate” • reported many times (see e.g. Xin at Muon Week March 26th ) An example for Barrel A chambers • In the following, the dependence with background hit rate is reported •  next slide Mauro Iodice – Muon Week – Performance Meeting, May15th, 2013

14. EIL1Efficiency – Results @ differentLuminosities A DROP IN EFFICIENCY of about 3% isobserved from 2 1033 to 5 1033 From 20 to 50 kHz/tube • Region B • <L> ~ 4 1033 cm-2s-1 • Region A • <L> ~ 51033 cm-2s-1 • Region C • <L> ~ 3 1033 cm-2s-1 • Region D • <L> ~ 21033 cm-2s-1

15. Efficiencydrop with Tube Hit Rate • Good agreement with extrapolated efficiency from tube hit rates and a ~750 ns dead-time after each hit Measured Extrapolation with tube hit rate Mauro Iodice – Muon Week – Performance Meeting, May15th, 2013

16. Summary • Results on MDT performance studies with 2012 data mature for a CONF-Note • Background hit rates: need re-analyses on different runs/Lumi (easy) • Resolution studies: • -- Procedure established • -- Resolution measured with two methods agree • -- No degradation of resolution observed up to a tube hit rate of ~55 Hz/cm2 (as expected) • Efficiency studies: • -- Procedure established • -- Drop in efficiency observed in the Endcap Inner chambers (mainly EIL1 – following the expectations) • -- Map of efficiencies per chambers to be done • Comparison with simulations: • -- Not started yet. Need to check available data sample quality/feasibility/reliability