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Track Fitting and Comparator Results

Track Fitting and Comparator Results. Emu meeting @ UC Davis Feb. 26, 2005 Yangheng Zheng University of California, Los Angeles. Motivation & Introduction Results. Motivations. Check output from comparator chips (for both ME2/2 and ME1/1)

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Track Fitting and Comparator Results

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  1. Track Fitting and Comparator Results Emu meeting @ UC Davis Feb. 26, 2005 Yangheng Zheng University of California, Los Angeles • Motivation & Introduction • Results

  2. Motivations • Check output from comparator chips (for both ME2/2 and ME1/1) • Get familiar with Stan’s track-fitting utility package (TrackFnd) • Test the unpacking software (ORCA/EmuDAQ) for test-beam 2004 data • Look at ME1/1 data from TB2004 Emu meeting @ UC Davis

  3. Stan’s Track Fitting Framework • Pedestal Subtraction • Precision Sampling Time  buckeye shaping • Cross Talk is a function of ts (capacitative+slightly resistive coupling between adjacent strips)  lookup table • Cathode Noise Correlation  unfired events • Fitting Gatti distribution  hit position / each layer • Track Finding  Kalman Filter • Track Fitting  A straight line least squares fit • Details can be found:http://www.physics.ohio-state.edu/~durkin/testbeam03/TrackFnd.htm Emu meeting @ UC Davis

  4. Data for Gatti Fitting INPUT DATA: strips time bins Largest pedestal subtracted ADC value OUTPUT: track hit position for each layer through the least squares fitting Emu meeting @ UC Davis

  5. Something New • New interface between TrackFnd and ORCA/EmuDAQ • Add options of gMinuit for fitting distributions of buckeye and Gatti • Change pedestal subtraction method • New constants for ME11 • cross talk • cathode noise correlation • Gatti parameters • strip width and no staggering Emu meeting @ UC Davis

  6. Buckeye Shaping 4*tc Emu meeting @ UC Davis

  7. Peaking Time tc ME22 (tc33.25ns) ME11: smaller gas gap and wire spacing  shorter drifting time ME11(tc28ns) Emu meeting @ UC Davis

  8. Peak Charge Time Bins ME22 (TB2003) ME22 (TB2004) ME11 (TB2004) Emu meeting @ UC Davis

  9. Pedestal Subtraction • Standard method: subtracting first two time samples • Method 2: pedestals  empty event (lookup table for every strip) • Method 3: pedestals  fitting all available time samples for every event (buckeye shape + constant pedestal) Emu meeting @ UC Davis

  10. Pedestal Subtraction (cont.) ME22 (TB2004) Method 1 – Method 2 Method 3 – Method 2 Mean 1.041 RMS 3.17 Mean 4.322 RMS 5.901 Emu meeting @ UC Davis

  11. Pedestal Subtraction (cont.) ME22 (TB2004) ---- Method 1 ---- Method 2 ---- Method 3 Emu meeting @ UC Davis

  12. Cross Talk • a function of ts • determined by tracks passed within 0.05 strip width of the center of the strip ME22(TB2003) ME22(TB2004) ME11(TB2004) cross talk fraction small statistics ts(ns) Emu meeting @ UC Davis

  13. Cathode Noise Correlation • Determined from unfired strips • For time bins i and j, • For time bins 3, 4, 5, 6 (ADC counts) • For ME22, TB2003 and TB2004 show similar results • ME11 shows different noise correlation • No correlations between adjacent strips’ time bins (<1 count) ME22 (TB2003) ME22 (TB2004) ME11 (TB2004) Emu meeting @ UC Davis

  14. Gatti Parameters • half gas gap (h parameter) • configuration: ME22 4.75mm, ME11 3.00mm • fitting: ME22 4.91mm, ME11 2.99mm • strip width • ME22 8.5-16.0mm, ME11 3.15-7.6mm • number of wire group per layer • ME22 64, ME11 48 • strip staggering • ME22 0.5 strip, ME11 no staggering Emu meeting @ UC Davis

  15. 2 of Gatti Fitting = 0.08 for ME22 NDOF: 9 - 3 - 1 = 5 ME22 (TB2004) ME11 (TB2004) Mean 4.99 RMS 3.16 Mean 4.999 RMS 3.16 Entries Entries Investigating the large tail effect 2 2 Emu meeting @ UC Davis

  16. Event Displays ME22 (TB2004) ME11 (TB2004) Emu meeting @ UC Davis

  17. Residue (3rd Layer) 3rd layer removed from track fitting ME11 (TB2004) ME22 (TB2004) sigma=0.0177 sigma=0.0178 Emu meeting @ UC Davis

  18. Comparator Ouput Resolution fitted track position - comparator output Emu meeting @ UC Davis

  19. Left Half Hits vs Right Half Hits wrong output due to the ambiguous charge difference (see next slide) Emu meeting @ UC Davis

  20. Output Probability wrong assignment due to the ambiguous charge difference Emu meeting @ UC Davis

  21. Output Efficiency comparator output residue within ¾ strip correct strip# output correct comparator output Emu meeting @ UC Davis

  22. Summary • Unpacking software seems robust • Small changes applied to TrackFnd class • For ME22, results of track fitting of TB2003 can be fully reproduced. • For ME11, the large tail effect of 2 and systematic errors are under investigation • Comparator chip produced reasonable results for both ME11 and ME22 Emu meeting @ UC Davis

  23. Next • need to understand ME11 data better • more refinements can be done • gain effect • cross talk as a function of chamber position • geometry constants Emu meeting @ UC Davis

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