1. Intra-String Muon Timing
Dmitry Chirkin, LBNL

2. Method of verification
For a given string choose a DOM X
Reconstruct data using hits on the chosen string excluding hits in DOM X
Find a maximum in the distribution of time residuals of the leading hits in DOM X from the reconstructed tracks
For tracks passing sufficiently close to the DOM X this maximum should be close to zero
DOMs not functioning properly will have suspicious residual distributions

3. Dataset
14 days (last week of February and first week of March) of PnF data was used. E.g. ~14/50=6.7 hours of data
Although tcal file were available for some runs, no time recalibration was performed for consistency
events with multiplicity 8 were extracted from the .hit files and compressed into new_ .hit files to minimize network file access to the data when running on multiple nodes
Calculation was performed on 60 npx 1 GHz nodes, took about 42 hours per node, 2520 cpu-hours alltogether

4. Quality cuts
Data was analyzed with and without quality cuts, e.g. for early data Feb 1:
Final results are based on the analysis with quality cuts:
 distance d1,2 from reconstructed track to DOM: 10 meters
 zenith angle 170<th1,2<180
 zenith angle quality: -3<th2-th1<3
 reduced llh: rllh1,2<6.5
All given for track reconstructions:
 1 (simple track) and
 2 (joint positional-energy track).

5. Residual distribution fits

6. String 21
60 DOMs working
no significal outliers
rms=1.90

7. String 29 58 DOMs working insufficient statistics for DOM 58
DOMs 59 and 60 are missing
rms=1.82

8. A DOM with insufficient statistics

9. String 30 59 DOMs working (DOM 23 missing)
DOMs 45, 46, 47, 48, 49, 50, 51, 52 have insufficient statistics
rms=3.11: somewhat high due to many failing fits

10. String 38 58 DOMs working no significal outliers
insufficient statistics for DOM 58
DOMs 59, 60 missing
rms=2.22

11. String 39
56 DOMs working
DOMs 1, 21, 22, 23, 24, 60 have insuffivient statistics
rms=2.21

12. String 40
56 DOMs working
DOMs 45, 46, 47, 48, 53, 54, 55, 56, 57, 58, 59, 60 have insufficient statistics
rms=3.46: somewhat higher due to many failing fits

13. String 49
60 DOMs working
DOMs 17, 18, 19, 20, 29, 32, 33, 34, 35, 36, 59, 60 have insufficient statistics
rms=2.72

14. String 50
51 DOMs working
no significal outliers
rms=2.33

15. String 59 58 DOMs working DOMs 57, 58 have insufficient statistics
rms=1.90

16. Summary string 21: 60 DOMs present in data 60 confirmed
alltogether 516 DOMs present in data; 472(491) confirmed

17. Muon verification web page