September 24, 2014 Calibration

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GlueX Calibration Meeting
Wednesday, September 24, 2014
11:00 am, EDT
JLab: CEBAF Center, F326

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  1. Announcements
  2. Collaboration Meeting
  3. Commissioning Planning updates
    1. CDC
    2. FDC
    3. FCAL
    4. BCAL
    5. TOF
    6. Start Counter
    7. Trigger
  4. Fall 2014 Commissioning Simulations updates
  5. Data Monitoring
    1. Commissioning Plan
    2. Data Monitoring Database & Histograms
  6. AOB


Attending: Sean, Amiran (NU); Mark I., Simon, Beni, Eric, Andrei S., Mike S., Mark D., Eugene, Elton, David L., Sergey F. (JLab); Curtis, Paul, Naomi (CMU); Matt (IU); Ahmed, Noemi, Tegan, Zisis (Regina); Justin (MIT); Brenden P. (UConn); Kei (ASU)


  • The latest accelerator schedule has the machine starting around Oct. 9
  • David L. has written up new documentation about Online Monitoring plugins
  • David also mentioned that Sergey F. has a new system for loading the DAC values onto the readout boards. It will be discussed in more detail in the online meeting in the afternoon.

Commissioning Planning updates


  • Beni reported that there have been problems with the CDC DAQ since the new fADC125 firmware was installed, with a variety of problems showing up on different boards. It's unclear at this point if it's a problem with the boards or the firmware.
  • The new fADC125 firmware does report pedestals - modes 1,2,3,4, and 8 are supposedly supported.


  • John Z. is working on integrating the pi0 calibration code into a DANA plugin.
  • Matt asked about the documentation for the Online_Monitoring_plugins.


  • Incremental progress is being made at Regina. Andrei and Noemi are looking at low-level calibration values, mainly with cosmic data. A long-standing confusion about cosmic rates has been lately understood.
  • Will McGinley is looking at BCAL calibrations using pi0's and making progress estimating rates.


  • FSU has collected 2M cosmic events. Sasha O. is working to understand these data and refine his calibration programs. There are some difficult parts to understand in the data, but this is mostly because the cosmic tracks are more vertically oriented than tracks from photon beam reactions. Photon beam data is expected to be much easier to understand. There should be enough information by now to make a good-enough global alignment of the TOF, and Sasha is pursuing this.

Start Counter

  • The first version of the fADC250 DAC adjustment has been made. The characteristics of the polished paddles are different than those of the prototypes used to study calibration procedures before, so they will have to be looked at afresh, probably with photon beam data.


  • Mark I. pointed out that changing the DAC values on the fADC's is not the same as calibrating the pedestals. There was much discussion on this point. Eugene pointed out that its reasonable to call it a pedestal "adjustment".


  • We then looked at the wiki page for the trigger commissioning plan. This was discussed in the trigger meeting on Monday, substantial changes were suggested, but it hasn't been updated since then.
  • Probably we will start with just an FCAL trigger before bringing in the BCAL
    • One big question is if we need to exclude the inner rings of the FCAL from the trigger. This will require seeing the actual beam.
  • Another outstanding question is if we can read out the whole detector. So far, nearly all ROCs have been read out at once, but not all of them. There have been problems reading out over VME.


  • Elton brought up the topic of how to treat the TDCs for discussion. The problem is that normally we would use the RF times as a reference for the times reported from the TDCs, but we will not have that this fall.
  • There was much discussion on how to handle this. The best suggestions seemed to be to use the Start Counter, Pair Spectrometer, or Tagger times as reference, if possible. The trigger time has too much jitter and is not precise enough to use as a reference.
  • The fADCs do have good timing capabilities, but we would like to be able to commission the TDCs this fall.
  • Elton will gather opinions for a discussion during the Collaboration Meeting.,


  • Simon has updated the commissioning simulations with an extended model of the beamline geometry and an extended target region, including the plastic beampipe cap and the air the photon beam will have to pass through.
  • Simon and Sean have been looking at detector rates.

Data Monitoring

  • Paul is coordinating the offline analysis of the Fall commissioning data. He, Kei, Sean, and Justin are developing tools for the monitoring of this data. They had a meeting on Friday to start making plans, and Paul is reporting on the current state of these plans.
    • Paul went over the wiki pages specified in the agenda in detail, which outline a plan for monitoring data analyzed bother online and offline, and the variables that they plan to analyze.
    • To summarize, the detector hit data will be monitoring using the plugins and histograms from the online monitoring effort. We will then check to see if these histograms can be reproduced using the offline reconstruction.
    • Reconstructed calibration and physics values will be checked by running over a selection of runs from tape.
    • These results will be collected in a set of web pages, where both results for a particular run and as a function of time can be investigated.
    • This plan isn't set in stone, and will rely on the input from the various detector groups. Updates on this effort will be given at the Calibration and Offline meetings.
  • Curtis suggested that we should run over the data as much as possible in beginning.
  • Eugene asked if the data would be available in a format simpler than EVIO, e.g. ROOT Trees.
    • Making ROOT trees of all the data collected this fall would severely increase our data footprint, but David L. pointed out that ROOT trees could be created on demand using the DAQTree plugin.
    • Curtis and Matt advocated using the standard sim-recon software framework, since the detector hit objects and their associated information are available in that framework even if the full track/shower reconstruction isn't run.
  • Sergey F. has another tool for online monitoring, but it is tied into the readout lists, so it is not clear if it would be useful for this effort.
  • Eugene and Zisis asked if there would be any sanity checks of the data built in, or any monitoring that would proactively bring problems up. The consensus was that this would be good to have at some point, but since the first data will be of unknown quality, it would be best having as many eyes looking at it as possible.
  • Mark I. said that it would be better to pull the run conditions from online databases. The currently existing online DBs can be replicated so that they can be accessed by the outside world.
    • There is a run conditions database which is close to being finished, but is waiting for Dmitry to put on the finishing touches. Sergey has been working with it as well, and said that the use of this DB could be enabled with a few simple changes. Note that some of the values we are interested in will probably be put in the data stream.
  • There were requests for an EVIO file of simulated bggen data to use for development purposes, and David L. provided one at the following location: /volatile/halld/home/davidl/2014.09.24.bggen_evio/rawevent_000002.evio