GlueX TOF Meeting, July 19, 2016

From GlueXWiki
Jump to: navigation, search

GlueX Time-of-Flight Meeting
Tuesday, July 19, 2016
11:00 am EDT
JLab: CEBAF Center, Room F326/327


  1. Announcements
  2. Review of minutes from the previous meeting
  3. PMT Gains Average MIP pulse from cosmics
  4. New Cosmic Data
  5. Base design
  6. Calibration Updates
  7. NIM paper



Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2016 on the JLab CUE. This directory is accessible from the web at .



  • FSU: Brad Cannon, Sasha Ostrovidov
  • JLab: Fernando Barbosa, Eugene Chudakov, Mark Ito (chair), Simon Taylor, Tim Whitlatch, Beni Zihlmann

There is a recording of this meeting on the BlueJeans site.

Review of minutes from the previous meeting

We went over the minutes from July 12.

  • Beni has changed the range on the ADCs to 0.5 V full-range from 2 V.
  • Tim commented on the schedule for a major re-work of the TOF. The DIRC arrives in July or August 2017. If the Spring run ends early, there will be a substantial window for TOF work. There is some independence of the DIRC installation and TOF work; there are stages that can be done a good bit in front of the TOF/FCAL. The DIRC plan is to install the frame, all of the bar boxes and one of the mirror boxes.
  • Mark talked to Alex Governale of Hamamatsu on Friday to get started on quotes for 24 of the H10534 MOD assemblies. Ardavan Ghassemi should be back this week.
  • Beni talked to Sasha Somov and Vladimir Popov about an amplifier in the PMT bases. He is concerned that the design for the tagger hodoscope had AC-coupled output. That would be unacceptable for the TOF.

PMT Gains

Average MIP pulse from cosmics

Sasha presented results from results from tests he did on a test set-up he brought back to life at FSU. He was able to measure pulses from minimum ionizing cosmics at various voltage settings. The tubes he used had intrinsic gain a factor of two less than those that were installed in the TOF. He plots and fits the peak voltage vs. HV setting. Sasha will look up the fit parameters and send them out.

Cosmic Ray Running

Beni took some cosmic data in the Hall with the new ADC settings and lower voltage settings. He showed some waveforms.

TOF signals with 1250V HV and 0-0.5V ADC dynamic range from cosmic data. This gives 0.125mV per ADC bit
or 80 ADC channels above base line for a 10mV threshold.
TOF Crate run11697 event4.gif TOF Crate run11697 event8.gif

More analysis to come.

Base Design

For our benefit, and especially for Fernando, Beni gave us a guided tour of the PMT bases, both for the 10-stage tubes we are using in the Hall and the 8-stage tube Paul Eugenio dropped off last week:

  • PMT-base 8-stage tube:
    IMG 20160711 131636.jpg
  • PMT-base 10-stage tube:
    IMG 20160624 081351.jpg