Loading   the   HAPPEX   Trigger  

Robert Michaels, rom@jlab.org, Jefferson Lab Hall A, March 1999

This file:     www.jlab.org/~rom/happex_trig.html

• PURPOSE:   To load the scintillator-based or HAPPEX-based trigger.

The trigger for the spectrometer DAQ can either require the scintillator plane S2 or the HAPPEX detector. Its best to use scintillator trigger for alignment checks and HAPPEX trigger for Q^2 check.

• USAGE:    

Login to adaqh2 (or h3 or h4 -- an HP-UX machine) as the "adaq" account. Type "trig_parity". Answer the obvious question about what kind of trigger you want. Usually choice 1 or 2. Then a GUI called XTrigMang will pop up. Press the button "Download All". This takes about 3 minutes, after which you can tell its finished because the XTrigMang window becomes alive again (and the window from which it started says something about S3, the last thing that got downloaded). Now press the "Quit" button.

• TO DO A SPECTROMETER DAQ RUN:    

After downloading the correct trigger, make sure the HAPPEX detector is switched over to the spectrometer DAQ. There is a relay switch which switches from HAPPEX DAQ to spectrometer DAQ. Adjust the HV on the detectors (the values should be written somewhere easy to find). Turn on the VDCs and scintillator HV. Important:   One should never run high intensity when these detectors are on. A reasonable upper bound is less than 50 kHz in the elastic peak. Do a spectrometer run (adaqs2 computer, adev account, press StartRun, EndRun in runcontrol there). Analyze the data with espace, see www.jlab.org/~rom/happex_espace.html   for details.