GlueX TOF Meeting, November 17, 2015

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GlueX Time-of-Flight Meeting
Tuesday, November 17, 2015
11:00 am EST
JLab: CEBAF Center, Room F326/327


  1. Announcements
    1. new TOF scaler gui
  2. Review of minutes from November 3
  3. TOF Points
  4. Calibration Status FSU Very rare Good Event Overwhelming majority of events
  1. Calibration Status JLab
  2. Hot Check-Out
  3. Loan TJNAF#44283 to Florida State Expiration
  4. NIM Article



Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2015 on the JLab CUE. This directory is accessible from the web at .



  • FSU: Hussein Al Ghoul, Brad Cannon, Sasha Ostrovidov, Aristeidis Tsaris
  • JLab: Mark Ito (chair), Simon Taylor, Beni Zihlmann

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

New TOF scaler GUI

Paul Mattione has created a new TOF scaler GUI some months ago. Sasha commented that he used it to discover the bad FADC mentioned below.

Review of minutes from November 3

We went over the minutes. Sasha has been taking data successfully; ROCTOF1 has not been crashing after the bad FADC was found and replaced.

Brad plans to be at the Calibration Meeting tomorrow where the Calibration Challenge will be discussed.

"Random" TDC Calibration Offset

Beni described a problem with TOF Points that he uncovered by looking at the event display. Occasionally he saw hits missing in the display when they were present in the raw data. This was traced to a difference in how one of our calibration constants was obtained versus how it is applied. The scheme to disambiguate the 6-fold ambiguity in the CAEN TDCs had different indices for the identification of the correct cyclic permutation of the pattern of shifts. One out of six events (randomly) would be shifted from nominal. This was resolved by changing the constant to agree with what is used in reconstruction. This fixes it for the Spring-15 run. The problem remains there in the Fall-14 data.

Calibration Status, FSU

Sasha showed two events:

He is having problems making progress with the cosmic calibration since the good events only contribute about one part in ten thousand to the event sample. He continues to explore different DAQ parameters to try to enrich the sample.

Hot Check-Out

It turns out that Aristeidis and Mark went through the checklist last time. Mark will give it a shot this time. This needs to be done by next Wednesday.

Equipment Loan, JLab to FSU

The loan is up for renewal. Paul Eugenio is aware of the situation.

NIM Article

Beni talked to Paul about the status of the article. It has been on the back burner lately. Beni intends to contribute a section on calibration to the draft.