1. T585 analysis status 2005/12/02 HIDEYUKI SAKAMOTO This analysis was done by RUN#1224-1228(+1.0 GeV/c normal beam run) For the problem of small light yield of Station#4 Contents ADC distribution (just for checking) Timing cut by Level1Acceptance P.E. distribution (pion/proton) for HIT & Tracking Fiber distribution (pion/proton) for HIT & Tracking Discussion

2. ADC distribution after common-mode subtraction AFE 104AFE 107 There were no signals on this MCM during RUN# 1224- 1232

3. ADC distribution after common-mode subtraction AFE 106AFE 105

4. Time offset of each station signal at VLPC STATIONTOFWAVEGTOTAL #4 proton pion 10.50 0 6.00 16.50 6.50 #3 proton pion 11.18 0.50 0000 11.18 0.50 #2 proton pion 11.65 0.85 0000 11.65 0.85 #1 proton pion 13.00 1.83 0000 13.00 1.83 TOF: (calculated) TOF from T1 counter (w.r.t. TOF of pion @ station#4) WAVEG: 6 nsec delay in 1.2m-long internal waveguide of station#4 (velocity is assumed to be 50 (nsec/m)) In this analysis, common criteria is applied on all stations for proton : 35300<L1A<36000 for pion : 35300<L1A<36500 Unit: nsec (1 TDC count=25psec) @1 GeV/c 213 TDC cnts difference

5. P.E. vs. L1A STATION 1 PROTON & PION are separated by TOF @ D1&D2 counter BLUE: PION RED:PROTON : 35300<L1A<36000 : 35300<L1A<36500 All hits > 2.5 p.e.

6. P.E. vs. L1A STATION 2 BLUE: PION RED:PROTON : 35300<L1A<36000 : 35300<L1A<36500 All hits > 2.5 p.e.

7. P.E. vs. L1A STATION 3 BLUE: PION RED:PROTON : 35300<L1A<36000 : 35300<L1A<36500 All hits > 2.5 p.e.

8. P.E. vs. L1A STATION 4 BLUE: PION RED:PROTON : 35300<L1A<36000 : 35300<L1A<36500 All hits > 2.5 p.e.

9. P.E. distribution Station 1 All hits > 2.5 p.e. BLUE: PION RED:PROTON V-view W-view X-view

10. P.E. distribution Station 2 All hits > 2.5 p.e. BLUE: PION RED:PROTON X-viewV-view

11. P.E. distribution Station 3 Overflow events All hits > 2.5 p.e. BLUE: PION RED:PROTON Overflow events X-viewW-view

12. P.E. distribution Station 4 All hits > 2.5 p.e. BLUE: PION RED:PROTON V-view W-view X-view

13. P.E. distribution Station 1 PROTON 14.5 p.e. Hits on reconstructed track PROTON 15.9 p.e. PROTON 16.9 p.e. V-view W-view X-view BLUE: PION RED:PROTON

14. P.E. distribution Station 2 PROTON 18.1 p.e. Hits on reconstructed track BLUE: PION RED:PROTON PROTON 15.2 p.e. X-viewV-view

15. P.E. distribution Station 3 VIEW X PROTON ? p.e. Hits on reconstructed track BLUE: PION RED:PROTON VIEW W PROTON 14.0? p.e.

16. P.E. distribution Station 4 VIEW X PROTON 9.3 p.e. Hits on reconstructed track VIEW V PROTON 9.0 p.e. VIEW W PROTON 9.2 p.e.

17. Light yield of protons #1#2#3#4 X14.518.1?(fail)9.3 V15.915.2N/A9.0 W16.9N/A14.0?9.2 Station#4 is 40-50% smaller than others Results of Gaussian fitting on proton data (unit: p.e.)

18. Fiber hit distribution STATION 1-2 All hits > 2.5 p.e. BLUE: PION RED:PROTON STATION 3-4

19. Fiber hit distribution STATION 1-2 BLUE: PION RED:PROTON Hits on reconstructed track STATION 3-4

20. Discussion -why so small? Wrong gain estimation? –Maybe NO. (station#3 and #4 were using the same cassette and both gain was estimated by the same way (channel by channel) by LED run) Timing? –NO. (“edge” can be seen, so signal was in gate.) Light loss at 1m additional waveguide? –NO. (Att.=7.7m => 1-exp(-1/7.7)=0.12 Using proton data; 15p.e.(data @station#1-3)*0.88=13.2 p.e. <=30% larger than 9p.e.(data @station#4)) So, I think the light was truly small before coming into VLPC. As the possibility, –Fibers were damaged by some reason? But proton data says fibers@station#4 can emit 10p.e.. –Bad mirror? (as Alan said) –Connection loss? @ station side, @ internal waveguide, …. #1#2#3#4 X14.518.1?(fai l) 9.3 V15.915.2N/A9.0 W16.9N/A14.0 ? 9.2