1 MDT P ERFORMANCE WITH 2012 C OLLISION D ATA C ONTENT OF THE CONF-NOTE Mauro Iodice Muon Week – Muon Performance Meeting, May 15 th, 2013

2 I NTRODUCTION Mauro Iodice – Muon Week – Performance Meeting, May 15 th, 2013 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 !

3 Mauro Iodice – Muon Week – Performance Meeting, May 15 th, 2013 MDT P ERFORMANCE C ONF N OTE – P ROPOSED L IST OF C ONTENT 1.MDT tube hit rate Vs Luminosity -- Tube average hit rates per chamber Vs Luminosity -- Saturation effects at high rates ??? (see P.Fleischmann Muon Week March 26 th ) 2.MDT Resolution Vs Drift Radius -- Tube hit Residuals: Establish fitting procedure -- Resolution: Definition and methods -- Resolution measurement for different types of chambers -- Comparison among different methods -- Comparison of results with different track pT selection: check results with curved segments fits at low pT -- Dependence with tube hit rates 3.Efficiencies -- Definition (Hardware efficiency / segment reconstruction efficiency) -- Efficiencies Vs radius for different types of chambers -- Dependence with tube hit rate 1.Comparison with simulation (if available/feasible) starting project on possible aging effects of MDT tubes Vs Integrated luminosity from MDT charge response (ADC) of the tubes Vs time (and Vs position, i.e. occupancy

4 MDT H IT R ATES (H Z / TUBE ) Compute average tube hit rate per chamber counting “out of time” hits in TDC spectra per chamber (and divide by num. tubes)  Hz/tube TDC Barrel A TDC Endcap A Highest rates on EIL1 chambers 37.5 KHz/tube Highest rates on EIL1 chambers 37.5 KHz/tube ~ cm -2 s -1 For ~ cm -2 s -1 Mauro Iodice – Muon Week – Performance Meeting, May 15 th, 2013

5 Average rate per tube per chamber normalized to average tube length x 3cm  Hz/cm 2 Average rate per tube per chamber normalized to average tube length x 3cm  Hz/cm 2 Highest rates on EIL/S chambers ~ 44 Hz/cm 2 Highest rates on EIL/S chambers ~ 44 Hz/cm 2 ~ cm -2 s -1 MDT H IT R ATES N ORMALIZED TO U NIT AREA (H Z /cm 2 ) Mauro Iodice – Muon Week – Performance Meeting, May 15 th, 2013

6 MDT R ESOLUTION V S D RIFT R ADIUS 1. MDT Resolution can be obtained by straight track fitting (segment) from “residual widths”  (r) and extrapolation errors: 1. Can also be obtained by the geometric mean of biased and unbiased hit “residual widths” ( NIM A538 (2005) )  Residual distribution  establish fitting function  Define “residual width” Mauro Iodice – Muon Week – Performance Meeting, May 15 th, 2013

7 MDT R ESOLUTION – F ITTING OF R ESIDUALS 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, May 15 th, 2013

8 MDT R ESOLUTION – R ESULTS Barrel ABarrel C Endcap AEndcap C Mauro Iodice – Muon Week – Performance Meeting, May 15 th, 2013

9 MDT R ESOLUTION – R ESULTS Provided we accept the fitting procedure and methods, this is now an established results. Many cross-checks performed (can be reported in the CONF-NOTE) All results are consitent Comparison with H8 Test-Beam data – CAVEAT: Test Beam data taken at fixed angles – better knowledge of extrapolation error Test-Beam results obtained with different residual fitting procedure ATLAS Collision data include slewing corrections (not included in TB) Mauro Iodice – Muon Week – Performance Meeting, May 15 th, 2013

10 MDT R ESOLUTION – D EPENDENCE ON H IT R ATE 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, May 15 th, 2013

11 EIL1 R ESOLUTION – R DIFFERENT L UMINOSITIES REGION A Region A ~ cm -2 s -1 Region B ~ cm -2 s -1 Region D ~ cm -2 s -1 Region C ~ cm -2 s -1 NO EVIDENCE OF RESOLUTION DEGRADATION UP TO cm -2 s -1 (~55 Hz/cm 2 ) Mauro Iodice – Muon Week – Performance Meeting, May 15 th, 2013

12 R ESOLUTION D EGRADATION FOR H IGH R ATES …as expected from Test-Beam under high background rates By S.ZIMMERMANN March 2004 (GIF) Mauro Iodice – Muon Week – Performance Meeting, May 15 th, 2013

13 MDT TUBE EFFICIENCY Definition, method, results in “low background rate” reported many times (see e.g. Xin at Muon Week March 26 th ) In the following, the dependence with background hit rate is reported  next slide An example for Barrel A chambers Mauro Iodice – Muon Week – Performance Meeting, May 15 th, 2013

14 EIL1 E FFICIENCY – R DIFFERENT L UMINOSITIES Region A ~ cm -2 s -1 Region B ~ cm -2 s -1 Region D ~ cm -2 s -1 Region C ~ cm -2 s -1 A DROP IN EFFICIENCY of about 3% is observed from to From 20 to 50 kHz/tube

E FFICIENCY DROP WITH T UBE H IT R ATE 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, May 15 th, 2013

16 S UMMARY 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/cm 2 (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