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%
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  Aug 16 - 19  Aug 17
spike rejection of TDCs in plane II = 23 ns
Aug 
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 changed from 23 ns to 13 ns
T.Galatyuk 20

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 TDCs seems 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. ToT as Function of Impact Angle into 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
particle  y x
angle

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

33. 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 ?
particle 
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 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
Time (from 0 to 100 ns) vs. Distance to wire (from 0 to 2.5 mm)

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

51. Few cells misbehave

52. Mass distributions p RPC Shift of the peak position
Mass „broadening“ scenario ;)
Visible in ToF and RPC
Also for other particles p
T.Galatyuk

53. Performance of Start- detector
Jerzy Pietraszko
Wolfgang Koenig
Performance of Start- detector
Alpha spectra from Am source measured for the outer and central segments of the start detector
Deterioration by 50 % within 5 days
Aug 15
Aug 18