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TRD#

Layout for physics runs in PbPb#

Note:

  • all QC tasks for TRD are running on the EPNs

Data size per sector#

The TRD has 18 sectors which should all produce a similar data size per TF. There can be two bands forming for each sector as is the case in the example above, because the number of calibration triggers per TF (which are very large in data size) depends on the readout trigger rate and is not fixed. This is OK, please respect the info box on the plot. If it is not green, please write a bookkeeping entry tagging TRD.

Tracklet distribution in half-chambers#

This plot shows the number of tracklets per half-chamber. The x-axis is the sector number. If you see one column completely empty please notify the TRD oncall.

The crosses on the plot are from a static half-chamber status map which needs to be replaced by a dynamic one to correctly cross out half-chambers where no data is expected because of hardware issues.

Eta-phi distribution of ITS-TPC-TRD tracks#

This plot will be empty if either ITS or TPC is missing in the run. This is expected and not a problem.

Eta-phi distribution for ITS-TPC tracks matched to at least 3 TRD tracklets. The PHOS-hole from abs(eta) < 0.2 and phi ~ 5 leads to almost no tracks in that region. No need to call TRD expert if plot does not look as example above. We are currently adding automatic checks.

Pulse height plot based on ITS-TPC-TRD matched tracks#

Ignore in case eta-phi distribution plot is empty or very sparsly filled.

This plot will be empty if either ITS or TPC is missing in the run. This is expected and not a problem.

A clear peak should be visible between time bins 0-4, followed by a plateau and a falling edge around 20. If plot does not look approximately as in the example above (and the track eta-phi plot is filled) please create a bookkeeping entry tagging TRD.

Pulse height plot based on TRD-only data#

In case the pulse height plot based on matched tracks is filled you can ignore this plot.

A peak should be visible between time bins 0-5. Call the TRD oncall if that is not the case, as there might be an issue with the trigger settings. The plateau region at larger time bins might not look as smooth as in the above picture in case there is a lot of pile-up.

Number of tracklets per event and TF#

We would like to be notified via bookkeeping entry in case either more than one distinct peaks are appearing in the distributions or in case there are entries in the underflow bin in either of the two histograms.

Raw data statistics#

This plots summarizes statistics on the raw data, such as the number of collected timeframes nTF, the number of triggers nTrig the number of calibration triggers nCalTrig, the number of tracklets nTrkklts and the number of digits nDigits. Furthermore, the readout rate and the calibration trigger rate are determined from the collected data and shown in the plot. Please note that it is normal that the readout rate is lower than the interaction rate due to TRD dead times. The oncall shall only be called in case the plot is not filled at all.

Known issues#

QC plots for COSMICS are not consistent with the documentation.
- For the "Data sizes from HalfCRU header" plot shows deviations due to noisy sectors (values around 2500). This issue can be ignored till documentation is up to date.
- For the "Number of Tracklets per timeframe" plot has a double peak structure in COSMICS and a lot of entries in the underflow bin (around 90% of tracklets). The experts have been notified. The relevant log can be found here: https://ali-bookkeeping.cern.ch/?page=log-detail&id=80122. The issue may be fixed in future or the documentation updated.