GlueX Start Counter Meeting, October 30, 2023

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GlueX Start Counter Meeting
Monday, October 30, 2023
9:00 am EDT

Meeting information:
Benedikt Zihlmann is inviting you to a scheduled ZoomGov meeting.
Topic: Start Counter


    • Start_Counter_Operations
    • Geometry: SC match to tracks
    • Preparation for next year's running
      • FADC250_READ_THR 120: (Runs 41384, 120848) needs to be higher, 20 ADC counts above base line is too low. Full scale of 4096 bits is 500mV with a base line around 100 leads to 500mV/(4096-100) = 0.12mV / ADC count: So a setting of 20 ADC counts above base line corresponds to only 2.5mV
      • DSC2_THRESHOLD 50 60: this corresponds to 50mV for discriminator threshold setting.
      • while adc readout threshold is clearly set too low the discriminator threshold may be too high. Need to find compromise and better match.


present: Vivian, Eugene, Hovanes, Beni

Vivian: presented her work on the Start Counter timing calibration for some run during last years PrimeX run period run 111370. The notes and progress on this work can be found here. Also added to the agenda above. The current timing resolution obtained is of order 320ps and improvements are expected with using more statistics.

Beni: Reports on assessing the degradation of the Start Counter response of the years of operation using run 41385 as reference and compare this run to other runs and run periods. The findings are reported here.

Action Items


Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2023 on the JLab CUE. This directory is accessible from the web at .