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Tracking results from Au+Au test Beam

Tracking results from Au+Au test Beam. Jochen Markert For the Tracking group. Status. DST gen0: Almost full calibration of all detectors alignment of all detectors (Shower done by hand) NOW: second iteration of calibration and alignment (new procedures by Vladimir)

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Tracking results from Au+Au test Beam

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  1. Tracking results from Au+Au test Beam Jochen Markert For the Tracking group

  2. Status DST gen0: • Almost full calibration of all detectors • alignment of all detectors (Shower done by hand) NOW: • second iteration of calibration and alignment (new procedures by Vladimir) • Overall improved tracking performance • Kalman Filter almost ready • MDC dE/dx to be done • Investigations of tracking parameters ongoing

  3. Improvements S3: tracks +8% chi2 -10% wires +2.3% S5: tracks +17% chi2 -25% wires +11.5% S6: tracks +10% chi2 -31% Wires +12% V. & O. Pechenov

  4. Vertex Day 224 Field • Vertex fit for field runs uses 2 inner MDCs simultaneously • Sigma ~ 1.3 mm V. & O. Pechenov

  5. Vertex Day 227 No Field • Vertex fit for no field runs uses 4 MDCs simultaneously • Better resolution compared to field on runs • Sigma ~ 1.1 mm V. & O. Pechenov

  6. Cluster Search And Fitting

  7. Number of Layers in Segments • Solid line for cluster • Dashed line for fit • Cluster search requires 10 layers at minimum • Almost the same number of layers in cluster for MIPS and NonMIPS • Less wires accepted in fit for outer segment (average loss 2 layers) compared to inner segment (average loss 1 layer)

  8. Number of Wires in Segment • Solid line for cluster • Dashed line for fit • Cluster search required 10 layers at minimum • Less wires accepted in fit for outer segment (average loss 2 layers) compared to inner segment (average loss 1 layer)

  9. Number of Layers in Segment Required layers in segment: >= 10 layers >= 11 layers =12 layers

  10. Number of Wires in Segment Required wires in segment: >= 10 wires >= 11 wires >= 12 wires >= 13 wires >= 14 wires >= 15 wires >= 16 wires >= 17 wires

  11. Track Fit

  12. Drift Velocity vs. Electric Field • Drift velocity of Ar/CO2 higher compared to Ar/i-butane • No real plateau for Ar/CO2 • Drift velocity very low at low electric field values for Ar/CO2

  13. Drift Velocity Contours for MDCI Ar/i-butane Ar/CO2 • Strong inhomogeneous drift velocity contour for Ar/CO2

  14. Fit Deviation vs Distance from Wire Deviation = tmeasured – tcalculated • Systematic deviation visible • Origin: cal1/cal2 ? • Needs to be investigated separately for each wire

  15. Fit Deviation vs Distance from Wire • Systematic effect stronger for NonMIPS compared to MIPS

  16. Drift Time Resolution • Resolution shows strong detoriation close to the sense wire • Different shape for MDCI compared to other MDCs • Better resolution for NonMIPS

  17. Front end Setting Comparison

  18. Evaluating 3 Scenarios • Aug 15  • spike rejection of TDCs in plane II = 23 ns • Aug 16 - 19  • from august 16, 13:42:00 on the spike rejection of TDC in plane II changed to 13 ns • Aug 17 • 13:21:41 – 13:24:12 two runs with high threshold settings (0x60) and spike rejection of TDCs = 13 ns

  19. Plane I, Sector 3, Layer 1 • Rich structures in the measured drift data • Question: Contain to additional structures “good” measurements with wrong time measurement ? T.Galatyuk

  20. Plane II, Sector 3, Layer 1; 15 && 17-19 August Black curves = Day 227 Color = Day 229 – 231  spike rejection of TDCs has been changedfrom 23 ns to 13 ns T.Galatyuk

  21. Plane I, Sector 3, Layer 1 Thr.>0x30 Thr.>0x60 • Higher threshold reduce additional structures T.Galatyuk

  22. Plane I, Sector 3, Layer 1 Factor of 10 suppression of the small ToT satellite T.Galatyuk

  23. The combination of low thresholds (0x30) and 23 ns spike suppression of TDCsseems to be a better choice? T.Galatyuk

  24. Momentum Distributions RPC ToF • High spike rejection + low threshold or low spike rejection + low threshold seems to be featured T.Galatyuk

  25. Mass Distributions RPC ToF p p d 3He t T.Galatyuk

  26. Number of Wires in Cluster for different Front end Settings • MIPS selected • Low threshold + high spike rejection results in more wires in the cluster compared to standard setting

  27. Number of Wires in Cluster for different Front end Settings • NonMIPS selected • Low threshold + high spike rejection results in more wires in the cluster compared to standard setting • Less improvement compared to MIPS

  28. Number of Wire in Segment for different Front end Settings • MIPS selected • Low threshold + high spike rejection results in more wires in the cluster compared to standard setting

  29. Number of Wire in Segment for different Front end Settings • MIPS selected • Low threshold + high spike rejection results in more wires in the cluster compared to standard setting • Less improvement compared to MIPS

  30. Efficiency Studies • Fully reconstructed tracks: • inner + outer segment fitted • Runge-Kutta fit succeeded • Matched with Meta hit • NonMIPS : beta < 0.6 • MIPS : beta > 0.8

  31. particle  y x ToT as Function of Impact Angleinto the Drift Cell NonMIPS • Integration over distance from wire • 5 degree angle bins • Second bump at large ToT for MDCI due to strong drift velocity variation for ArCO2 angle angle

  32. ToT as Function of Impact Angleinto the Drift Cell MIPS • Second bump at large ToT almost vanished

  33. particle  Cell Efficiency from Segment Fit • Impact angle and distance from wire known from segment fit • Only accepted wires are taken into account • Reference are wires which should have given a signal • Efficiency limited due to segment fit ? • Low values MDCIV ? • Structures in MDCI ? 70% 70% 75% 58%

  34. Cell Efficiency from Segment Fit • Better efficiency compared to MIPS • Still the same questions as before 73% 82% 80% 58%

  35. Cell Efficiency from Segment Fit • Difference between efficiency of MIPS and NonMIPS

  36. Cell Efficiency from Cluster • Impact angle and distance from wire known from segment fit • wires from cluster are taken into account • Reference are wires which should have given a signal • Efficiency not limited due to segment fit, but noise or double hits are counted as “good” 80% 84% 90% 84%

  37. Cell Efficiency from Cluster • MDCIV now at high efficiency • Conclusion: segment fit looses wires due to noise or wrong measurements (hardware, geometry,cal1, cal2) 80% 90% 92% 90%

  38. Cell Efficiency from Cluster • Difference between efficiency of MIPS and NonMIPS

  39. Cell Efficiency results

  40. Layer Efficiency • Layer efficiency calculated from clusters • Only clusters are selected which contain no multiple used wires • Event multiplicity 10-30 selected, max multiplicity per sector < 8 tracks • Long spike rejection + low threshold seems to be the most efficient combination T.Galatyuk

  41. Probabilities T.Galatyuk

  42. Comparison between Au+Au and Ar+KCl • Layer efficiencies comparable • 40 degree layers show lower efficiencies T.Galatyuk

  43. Some layers show same efficiency structures • The complete chamber has been build new. Front end electronics could be the reason T.Galatyuk

  44. Thank you!

  45. Time (from 0 to 100 ns) vs.Distance to wire (from 0 to 2.5 mm) Ar/i-butane Ar/CO2

  46. Number of layers in module

  47. Number of wires in module

  48. 13 ns, 0X38 23 ns, 0X38 23 ns, 0X60

  49. Velocity vs. Momentum x charge RPC TOF

  50. Time-of-flight spectrun in RPC b > 0 b < 0

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