T2K Run8 MUMON Summary

troubles, setting changes proton beam bunch width increased from run710058 : timing offset adjusted frequent timing error run720182 : timing fix applied timing module replacement, delay changed by 15ns from run720187 : timing offset adjusted IC attenuator 0dB  6dB from Run710098 EMTs installed ver.2, 3 : from Run71 ver.4 : from run74

history plots Run70,72,73,74 Run71 BSD files BSD is not reprocessed use updated one instead of BSD

profile center X stable within 2 cm Si & IC are consistent anti-correlation w/ proton beam position

profile center Y stable within 3 cm Si & IC are consistent anti-correlation w/ proton beam position

SSEM – Si correlation w/ angle corr.

profile width X 2~3 cm fluctuation Si & IC are consistent correlated w/ proton beam width

profile width Y 2~3 cm fluctuation Si & IC are consistent correlated w/ proton beam width

Si/CT history Horn PS current correction works very well w/ Horn PS correction Horn PS current correction works very well slightly decreasing after the correction ?

IC/CT history Horn PS current correction works very well w/ Horn PS correction calibration run (IC is 25cm displaced) attenuator 0dB  6dB Horn PS current correction works very well slightly increasing after the correction ?

Si/IC history IC attenuator 0dB  6dB Si / IC is gradually decreasing

investigation of Si yield decrease

run by run mean value history use run>=710098 ( IC attenuator setting change ) same vertical scales (2% full range)

run by run mean value history use run>=710098 ( IC attenuator setting change ) linear decrease  can be a radiation damage degradation rate ~ 1% / 5x1020 POT

bunch by bunch yield 1st bunch yield is decreasing faster 1st bunch 2nd bunch 3rd bunch 4th bunch 5th bunch 6th bunch 7th bunch 8th bunch 1st bunch yield is decreasing faster suggesting increase of tail (slow) component IC 8th bunch is saturating as beam power increase

proton beam bunch width bunch width affects Si/CT or Si/IC checked CT pulse width 50% of peak FWHM 10% of peak rise time decay time

proton beam bunch width drastic change on Nov.24 (run071058) variation after run71 is not monotonically cannot be a main reason of Si yield decrease

waveform comparison selected runs which have similar CT5 pulse width 1st bunch waveform normalized by CT5 1st bunch ppp averaged waveform (~1300shots), timing adjusted Run date power CT5 FWHM rise time 710229 Dec. 16 430 kW 94.8 ns 66.0 ns 720053 Jan. 17 440 kW 96.4 ns 66.5 ns 730034 Mar. 13 96.2 ns 65.7 ns 740035 Apr. 9 450 kW 95.2 ns 65.1 ns

CT5 waveform run710229 run720053 run730034 run740035

IC center ch waveform run710229 run720053 run730034 run740035

Si center ch waveform run710229 run720053 run730034 run740035 pulse height of Si signal is gradually decreasing

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