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Slice Test: Preliminary Data Analysis

Slice Test: Preliminary Data Analysis. S. Durkin The Ohio State University CSC ME/1/1 Meeting March 14, 2006. CatTrk Software. Existing Maverick Code used, modified, and check by many people written to analyze 2003 test beam data

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Slice Test: Preliminary Data Analysis

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  1. Slice Test: Preliminary Data Analysis S. Durkin The Ohio State University CSC ME/1/1 Meeting March 14, 2006

  2. 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

  3. 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 40sec time period) A Root Event Display was written in to Debug Tracking (following event displays from first two events in September Run 10010)

  4. Black point a knock-on eliminated from line fit.

  5. Poor Track: Angle of line does not match 2 other tracks. Last two points at very edge of Chamber only fit 2 strips.

  6. 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.

  7. Gatti-Fit Hit Resolution Strip Noise 3.2 ADC Counts • Require > 4 hits on track • Cathode Track Angle < 25 degrees 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

  8. 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

  9. 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)

  10. Gatti Hit Resolution 100 V increase yields a result much closer to Test Beam ME2/2/27 Sigma (hit pos – trk pos)(m) Rule of Thumb: 150V  2X gain Strip Position

  11. 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)

  12. 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.

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