Slice Test: Preliminary Data Analysis The Ohio State University S. Durkin The Ohio State University CSC ME/1/1 Meeting March 14, 2006 S. Durkin, ME1/1 Meeting March 14, 2006
CatTrk Software Existing Maverick Code used, modified, and check by many people written to analyze 2003 test beam data recently converted to CMSSW (only track finding/fitting working) very fast – 100 cosmic events/second (AMD Sempron 2.5GHz) Package Includes: Anode/Cathode Multi-Track Finding Calman Filters Gatti fits with cross-talk and Auto-Correlation Matrix (3 time X 3 charge bins) 3-D Track finding to Gatti points using Gatti Error matrix Track Error Matrix to Determine position/angle uncertainty Chi-square of Gatti Fits and Line Fits reasonable Fitting Constants: (averages used for this analysis) Full Calibration Constants now available thanks to Oana & Nicole Added to CatTrk software last Friday Gain, Cross-Talk, AutoCorrelation Matrices in Oracle Data Base see http://cmsdoc.cern.ch/cms/CSC/CERN/db.html S. Durkin, ME1/1 Meeting March 14, 2006
Cosmic Ray Data Data with ~ ten live chambers available since September Few have even touched these data sets Data obviously not as clean as Test Beam Low Momentum tracks Resolution may be effect by multiple scattering Some very messy cosmic showers interspersed (in January a DDU error state was tracked to hundreds of shower tracks arriving within 40sec time period) A Root Event Display was written in to Debug Tracking (following event displays from first two events in September Run 10010) S. Durkin, ME1/1 Meeting March 14, 2006
S. Durkin, ME1/1 Meeting March 14, 2006
eliminated from line fit. Black point a knock-on eliminated from line fit. S. Durkin, ME1/1 Meeting March 14, 2006
Angle of line does not match 2 other Poor Track: Angle of line does not match 2 other tracks. Last two points at very edge of Chamber only fit 2 strips. S. Durkin, ME1/1 Meeting March 14, 2006
S. Durkin, ME1/1 Meeting March 14, 2006
Large Angle Problem For Cathode Track Angles >30 degrees, hit resolution seen to degrade Gatti Fit Chi-Square 5 D.O.F. <20o Resolutions for hits within 1mm of strip edge Mean ChiSquare Hit pos. – line (strips) >30o Cathode Angle (degrees) Hit pos. – line (strips) Maybe not so surprising. At 30 degrees charge is deposited along ~0.57 cm of wire. S. Durkin, ME1/1 Meeting March 14, 2006
Gatti-Fit Hit Resolution Require > 4 hits on track Cathode Track Angle < 25 degrees Strip Noise 3.2 ADC Counts Near Center (poor) (ADC Counts) Very poor – half strip Resolution is 1400 m ME2/2/27 Resolution Estimated From width ignoring tails Charge 4.5 86.0 5.5 Error 71% 3% 60% Sigma (hit pos – trk pos)(m) Between Strips (ADC Counts) Charge -1.0 46.0 41.5 Error - 7% 8% Strip Position S. Durkin, ME1/1 Meeting March 14, 2006
Is 3600V High Enough? 3600V is the average chamber’s plateau knee History: Test Beam Voltages raised to 3650V, 3600V deemed too low! Landau peaks below design: peaks ~(80-110 ADC Counts) Design specs: peak 200 ADC Counts (12 bit ADC – 4096 ADC counts) Need to account for gain variations – within chamber and chamber to chamber… But Must Keep Voltage Low to Insure Long Chamber Life S. Durkin, ME1/1 Meeting March 14, 2006
HV Scan on ME2/2/27 Present trigger does not allow reasonable coverage of all chambers due to complex geometry. Arbitrarily choose one chamber. Many chambers peak even lower. Feb 24, 2006: take data at 3600V, 3650V, 3700V Sum 3 Adjacent Strips (ADC Counts) S. Durkin, ME1/1 Meeting March 14, 2006
Gatti Hit Resolution 100 V increase yields a result much closer to Test Beam Sigma (hit pos – trk pos)(m) ME2/2/27 Rule of Thumb: 150V 2X gain Strip Position S. Durkin, ME1/1 Meeting March 14, 2006
Gain Variation within Chamber Even with Gain constant Resolution is a Strong Function of Strip Width ME2/2/27 3600V Track with Anode Hits in Lower ¼ of Chamber (hit within 1mm Strip Center) Track with Anode Hits in Upper ¼ of Chamber (hit within 1mm Strip Center) = 0.1 strips = 1400 m = 0.042 strips = 440 m Hit Pos – Line Pos (cm) Hit Pos – Line Pos (cm) S. Durkin, ME1/1 Meeting March 14, 2006
Conclusion We have 20 chambers live. We do little more than check their data unpacks without errors. Presently there is no official CMSSW software beyond data unpacking We must monitor pulse timing, Landau peaks, layer efficiency … This NEEDs to Be Done…Now! Chamber Voltage was set to Lowest Average Plateau Value Voltages must be increase to get fine enough angular resolution Average resolution is not good enough Track resolution must be adequate in full chamber. S. Durkin, ME1/1 Meeting March 14, 2006