GlueX TOF Meeting, April 15, 2011

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Location, Time

Friday, April 15, 2011
2:00 pm EDT
JLab: CEBAF Center, Room F326


  1. Announcements
  2. Minutes from the last meeting
  3. Prototype Status [1]
  4. Contract Status



  1. ESNet: 8542553
  2. EVO: EVO site


  1. dial:
  2. enter access code followed by the # sign: 3421244#


Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2011-2Q on the JLab CUE. This directory is accessible from the web at .



  • FSU: Sasha Ostrovidov
  • JLab: Mark Ito (chair), Elton Smith, Simon Taylor, Tim Whitlatch

Minutes from the last meeting

We went through the minutes of the April 1 meeting. No significant comments were made.

Prototype Status

Sasha reported on work with the TDC from CAEN. He described the procedure he used for calibration that ensures differential linearity for the least significant two bits. See his slides for details. He will see what effect that has on time resolution using the two long counters in the prototype.

Time-walk Calibration Using Crossed TOF Counters

Elton described work documented in his recent note. He introduced the subject by noting:

  • the current proposal is to use leading-edge discriminators
  • Athens uses an LED for their calibration system, which does not excite the scintillator for the TOF.
  • GlueX has two planes of TOF, unlike CLAS where a laser system was used to give varying amplitude pulses. This gives a constraint: 4 time measurements from the two ends of crossed counters and 3 quantities to measure, x, y, and t.

See his note for details. The procedure outlined for time-walk corrections recovers the generated time resolution from the single particle events simulated.

Contract Status

Mark reported that the APP has been signed. Now we need to move on to the Statement of Work and the Sole-Source Justification.