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Another look to the BGO matrix calibration C.Voena INFN Roma. Signal windows in OSC waveform analysis. As in the paper, event by-event for PMT i (start of signal is determined from average time profile): Q i = Integral[0,115]ns S i = Integral[50,115]ns
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Signal windows in OSC waveform analysis • As in the paper, event by-event for PMTi • (start of signal is determined from average time profile): • Qi = Integral[0,115]ns • Si = Integral[50,115]ns • Ci = Integral[0,16]ns-0.27*Si mV S2 S1 In the paper S1/S2 is assumed to be 20% on the basis of 2007 results S1/S2=27% sample
Qsum(=Q1+Q2+Q3+Q4) distributions (50 GeV) central beam position Qsum Long tail at low total energy
Qsum and Q1 dependence on DownStream BC Y(tdc counts) Y(tdc counts) Qsum Q1 - Strange distributions at Y>0 and for some runs also at Y<200 and Y>-200 (Y= vertical coordinate of downstream beam chamber) - The tails of Qsum distribution are concentrated at Y>0 Cut at Y<0 and Y>-200 in what follows
Calibration procedure using Qi: minimize resolution Intercalibration constants k1i of all runs at 10-20-30-50-100-150-200 GeV at the three different position (21 runs) by minimizing: j=run number Overall calibration constant k from run at 50 GeV in position c
Results for Qsum in central beam position Linearity /E(GeV) Resolution 0.30/√E(GeV)+1.3% -1/√E(GeV) E(GeV)
Results for Qsum in beam position b) Linearity Resolution /E(GeV) 0.31/√E(GeV)+0.5% -1/√E(GeV) E(GeV) - Very non uniform behavior with respect to central position - beam position a) is in better agreement with central beam position - Minimizing linearity for all runs brings mean linearity in 0.8-1.2 range for all positions
Results for Cerenkov signal in central beam position Linearity /E(GeV) Resolution 0.42/√E(GeV)+2% E(GeV) -1/√E(GeV) - Optimizing the inter-calibration constants separatly for C and S improve resolution of few %.
Results for scintillation signal in central beam position Linearity /E(GeV) Resolution 0.47/√E(GeV)+1% -1/√E(GeV) E(GeV) - Optimizing the inter-calibration constants separatly for C and S improve resolution of few %.
Summary • - BGO matrix calibrated by minimizing the resolution • at all energies • - Low energy tails removed to apply this procedure • - Resolutions for beam in central position • - Linearity at <5% level except at 10GeV and 20-30 GeV • for Cerenkov signal • - Very different response when beam is sent in position c) • - Some improvement in resolution with respect to approach • that minimizes linearity but worse linearity for Cerenkov • signal C:0.42/√E(GeV)+2% Q:0.30/√E(GeV)+0.5% S:0.47/√E(GeV)+2%