General Idea

2. General Idea • Normalized QDC for each pixel • Data sets: • PP158 from 2009 (~3.5 Mevents) • BeBe from 2013 (13+30GeV, ~7Мevents) • We have histo for every pixel´s count where we can check all suspicious pixels • Good pixel: number of hits has to be in range of 8 sigma from average hits of neighbor pixels

3. Determination of good pixels For counting average hits from neighbor pixels, only GOOD pixels are included; Zero-, Over- and Under-Count are excluded!

4. Normalized QDC for ToF-L

5. Normalized QDC for ToF-R

6. Pixel’s hits for pp158

7. Pixel’s status

8. Pixel’s status

9. Pixel’s status

10. Pixel’s status

11. Overall statistic

12. QDC for good pixel

13. QDC for OverCount pixel

14. QDC for UnderCount pixel

15. Conclusion • Right wall still decent: 20 dead and 41 suspicious pixels • Left wall seriously damaged: 75 dead and 232 (!) suspicious pixels • Most probably reason: broken or unglued PMTs • Cannot be justify without opening cassettes • Almost all cassettes in the left wall need repairing! • Serious job: material (PMTs, scintillators), men work… • Question: do we need readout upgrade in this situation?

16. Thank you!