Please don't hesitate to contact the experts when something doesn't look right!!!
Troubleshooting Problems for help

Before your first shift at LArIAT
Check here so you're ready.

At the start of the shift

Before anything else: How to set up your shift station

Remember to call MCR (x3721) at the beginning and ending of each shift!!!
Main Control Room (internationally) +1.630.840.3721

  1. In the LArIAT e-log, fill out the Start of Shift Checklist
    1. Instructions to check how much remaining Wire Chamber Gas
  2. Find out from the shifter before you if there are any issues.
  3. Refresh and read the Run Plan:
    1. what beam request LArIAT wants
    2. any interruptions to expect
    3. special conditions or known problems

During the shift

The shifter is responsible for the beam and the detector health, data taking, logging what happens in the e-log,and maintaining data quality.

  • Fill out and submit the Every-2-Hours Checklist in the e-log.
  • If you have questions, use Google Hangouts: send an email to to get invitation.
  • If that doesn't work please call an expert! LArIAT Call List

Starting a new run

  • In the DAQ terminal window, type
    go 500
    Detailed DAQ instructions
  • The DAQ should make an e-log entry for you automatically.

During an ongoing run

Beam and detector health

  • ACNET to monitor the beam intensity and quality, especially:
    • the S60 page of ACNET (intensity constant and not too high)
    • the profile plots for MC7WC1 and MC7WC2. (beam is focused on target in MC7)
  • Synoptic (detector conditions alarms: everything on, not too much current, no temperatures too high, TPC safely submerged in LAr, etc..)
    • If the Wire Chambers trip too often (several times per hour), turn off the power supply! And call the run coordinator.

Data taking

  • Run Status Webpage to monitor the run status (run number, number of spills, numbers of triggers, etc)
    • Note that, on the Run Status Webpage, if the run time appears red, and the spills stop increasing, the run has come to a stop. It will also speak an audible alert, once. Start a new run immediately.
    • Sometimes the Run Status page freezes. Refresh it to check.
  • Useful: Recent run history


  • E-log site. As shifter, record anything of significance which is relevant to the experiment. This is the experiment's memory!

Data quality

  • Online DQM to check basic data integrity.
  • Event Viewer to see TPC events.
    • Normally we expect 10-20 beam events with 3 tracks or less, every spill. These "simple events" are easy to use for analysis.
    • If every beam event is too crowded and there are no simple events:
      • Check the Beams Division e-log to see if MTest is being tuned, which affects LArIAT's MCenter beam. Tuning often takes 10-25 minutes.
      • Consult the experts on Google Hangouts. They may ask you to call the MCR to request lower beam intensity.
    • If you decide to post some interesting event in the e-log please write the number of the spill/event in the title or content of the entry. It's much easier to search for them later!

Troubleshooting Problems

  • Most problems solved: Troubleshooting Page
    • Keywords: DAQ, kerberos, start run, crash, wire chambers, TDC, wire chamber controller, telnet, MWPC, reset, trigger, configuration, ASIC, interlock,
  • Still need help? Call an expert
  • If a VME Power Supply has to be turned off in an emergency situation (e.g. problem with TPC PMTs) - turn off the regulate function first, then put the decreasing voltage values in the quick ramp window, go to 0 and then turn off!

At the end of the shift

  • Make an entry in the e-Log using the form "Shift Summary" summing up the relevant information from the shift. For any other information to be posted in the e-Log during the shift use the "default" form.

    Remember to call MCR at the beginning and ending of each shift!!!

Remember to call MCR at the beginning and ending of each shift!!!