Last update: 03/14/2005 10:38:41 AM    by Nazim Khan

Running Fastbus Time Gains 

The time calibrator needs to be switched on.  

For a quick check of the electronic setting, go to the common run mode settings table. 

To provide a start for the fastbus, channel D on the 4-fold logic unit in the NIM bin above the fastbus needs to be unmasked.  Channels A, B, and C have to be masked. 

The DAQ run type is FBTIME.

A calibration run should be taken at least once a day. Since there is a signal in each channel for all events, it is only necessary to take up to 10,000 events for statistical purposes, this take about 5 minutes at 35Hz.

To determine the time gain calibration values and write them to database, run the FBGainCalc macros., 

   Step by Step:

  1. Make sure that there will be no beam for the next 2 minutes.
  2. The Time Calibrator should already be on. If it is not then turn it
    on.
  3. Make sure channel D is enabled (no pin) in the upper module of the TOF 4-fold
    logic unit.
  4. Set the Period = 0.02 microseconds and the Range = 0.64 microseconds
    on the time calibrator.
  5. Using the DAQ GUI start a run with writing of type "FBTIME" and trigger
    configuration "MINBIAS".
  6. Remove the Time Calibrator cable ( labeled TC Inhibitor) from the TTL
    output on the Time Calibrator enable gate/delay generator.
  7. Collect 10,000 events. This takes about 1 minute usually.
  8. Stop the run.
  9. Leave the Time Calibrator On and leave channel D enabled in the logic
    unit.
  10. Set the Period = 0.04 microseconds and the Range = 0.32 microseconds
    on the time calibrator.
  11. Plug the TC Inhibitor cable back into the TTL output of the gate/delay
    generator.
  12. Note in the Comments for the run the Range & Period used
  13. Make a note in the logbook that a FBTIME run has been taken.
  14. After taking the time calibrator data, please verify that the heartbeat is being generated.  The red LED on the time calibrator should be blinking at a rate of a few Hz.  If it is not blinking, press both red START buttons on the dual gate-and-delay generator (located to the right of the time calibrator) until the LED on the time calibrator starts blinking again.