T585 analysis status 2005/12/02 HIDEYUKI SAKAMOTO This analysis was done by RUN# (+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

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

ADC distribution after common-mode subtraction AFE 106AFE 105

Time offset of each station signal at VLPC STATIONTOFWAVEGTOTAL #4 proton pion #3 proton pion #2 proton pion #1 proton pion TOF: (calculated) TOF from T1 counter (w.r.t. TOF of 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 GeV/c 213 TDC cnts difference

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

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

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

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

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

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

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

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

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

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

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.

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.

Light yield of protons #1#2#3#4 X ?(fail)9.3 V N/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.)

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

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

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; p.e. <=30% larger than 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 can emit 10p.e.. –Bad mirror? (as Alan said) –Connection station internal waveguide, …. #1#2#3#4 X ?(fai l) 9.3 V N/A9.0 W16.9N/A14.0 ? 9.2