1. Far Detector Performance and Calibration
J. Musser
Indiana University
Minneapolis, July 2002

2. Summary
roughly 200 ‘plane trigger’ runs available for analysis in March-July time period.
A small number of cabling errors have been ‘fixed’ in the plex, reprocessing complete (at IU)
Improvement in time resolution: ~ 5% velocity resolution now observed.
Primary Data Analysis/Reconstruction Activities
Calibration Constant Refinement/Stability Studies
Demultiplexing Optimization
Detector Aligmment Studies
Up-going Muon Searches
Contained Event Analyses
The Future

3. Calibrations (1) Timing
T0s: Independent determination by Lee, Musser, Rebel,Tardiff.
Timewalk: Independent determination by Lee, Musser.
Studies indicate that calibrations hold at better than 1 ns over the March-July time period.
Calibration quality is sufficiently good at this time to consider batch data processing and production of DSTs.

4. T0 Calibration T0s vs Channel -15 ns < T0 < 15 ns Strip Meantime
Timing Residual s= 2.5 ns
L/R strip timing vs track position
predicts 2.2 ns.

5. TimeWalk Calibration
Pulse-height dependent tail on time residuals - correctable
by time walk correction.

6. Time Walk Correction Mean Time Residual (ns) ADC
T' = T - C1/(C2+ADC^1.2)
ADC

7. T0 Stability T0 differences between two data sets
separated by 2 months.

8. T0 Stability (2)
Stability is better than 1 ns over this period. However, some statistically significant differences are seen.

9. Velocity Resolution/Stability
Average 1/b RMS vs run, from March to the present. RMS is stable
at 8%
Average muon 1/b vs run, from March to the present. Average is stable to much better than 1%.

10. Calibrations (2) Pulse Height
Strip Attenuation (mapper data)
Inter-strip Normalization Using Muons
Stopping Muons Inter-Detector Normalization

11. Muon Pulse Height Distribution
Far Detector Data - Single End
Blue: Raw
Green: Clear Fiber Atten.
Yellow: Strip Atten.
Red: Path Length.
Black: Inter-Strip Norm.

12. Inter-Strip Normalization
# Events Used
in Calibration
vs Plane
Inter-Strip
Normalization
Factor
Distribution
(23% strip-strip
gain variations)

13. Inter-Strip Normalization
Mean Resp.
vs Plane
Raw
Mean Resp.
vs Plane
Corrected

14. Time Stability of Strip Response*PMT Gain
Restricted to first 120 planes (those planes instrumented
for entire period under consideration (March 15-July 1)
Response is stable to better than 1%

15. Stopping Muon Calibration

16. Demuxing Optimization
Optimization of ‘IU’ demuxer is ongoing, all pathological events sent to B. Rebel.
UMN group is working on an alternative demuxer, based on ‘global’ event analysis (rather than event swimming, as in IU code) Status will be reported in this meeting.

17. Detector Alignment
SM1 will be energized in the near future. This makes detector alignment studies very timely. There is now a group of people actively working on this. Results will be presented by Nelson, Lee, Boehnlein, Becker, and Viren at this meeting.

18. Alignment Using Muons (Post Nicolai)
Work Presented in 6/02 by R. Lee
Single Strip Tracking Uncertainty
is ~ 2.3 mm.

19. Alignment (2) Residual vs Plane - Outlier Planes Identified
(some associated with cabling errors)

20. Upgoing Muons
Searches for upgoing muons being conducted by Rebel, Musser, Lee, and Tardiff.
~ 6 candidate events (in my analysis)
Data from March to July 1 now processed.

21. Muon Velocity Distribution

22. Candidate Events

23. Horizontal Muon

24. Fully Contained Up-going Event

25. Contained Events
Most of this work is being conducted by Roy in conjunction with veto shield study.
Expect ~ 0.7 fully contained, reconstructed events in this data set.

26. Contained Event Candidate

27. Contained Event Candidate 2

28. Angular Distributions - Signal & Background

29. The Future
The state of calibrations and reconstruction is consistent with moving towards batch processing of data, and generation of DSTs.
Broader participation in reconstruction and analysis is highly desirable. The following steps will be taken to assist in this - thoughts on how we can do better are appreciated:
Maintainance of a ‘needed task list’ on MINOS web site.
Improve documentation for reconstruction software.
Begin batch data processing, making DSTs available to general users.