MCH

Quality Summary

[QC on EPN]

The left panel shows a summary of the automated checked on the MCH data, in a human-readable format. The top line describes the aggregated quality status, followed by a message suggesting the appropriate action according to the quality level:

• Bad: immediately inform the MCH on-call

• Medium: write a logbook entry, tagging MCH

• Null: the plots are completely empty. Check in DCS if MCH is in STANBY. If not, inform the MCH on-call.

The right panel shows a trending plot of the aggregated quality. The message in the left panel always corresponds to the most recent point in the trending plot.

If the quality in the trend plot is Bad for the whole duration of a run, MCH should be marked as Bad in the Bookkeeping flags for the run.

Quality Plots - Decoding and Pre-clustering

The following plots show the distribution of various estimators of the MCH data quality. Each horizontal bin shows the value of the monitored quantity, averaged over one Detection Element(DE). The vertical dashed lines show the boundaries between each of the 10 MCH chambers. An horizontal dashed line shows the threshold used by the checker to decide if a given detection element is considered good or bad.

The checker assigns an overall Good (green), Medium (orange) or Bad (red) quality flag to the plot, depending on the number and pattern of bad DEs. In general, the quality is still considered Good if only few DEs are bad. The quality is set to Medium if several DEs are Bad, but no significant impact on the detector acceptance is expected. If the number and pattern of bad DEs is such that the acceptance will be degraded, the quality is set to Bad.

The overall aggregated MCH quality is the logic AND of the qualities of the individual plots.

Fraction of Synchronized Boards

[QC on EPN - plot from the last QC cycle]

Green plot: good quality	Red plot: bad quality

The plot shows, for each Detection Element, the fraction of FEC boards that are properly synchronized. A given DE is coinsidered bad if the corresponding fraction is below the horizontal dashed line. The overall plot is considered Bad if the number and position of bad DEs is such that it significantly impacts the tracking performance.

Fraction of Boards not in Error

[QC on EPN - plot from the last QC cycle]

Green plot: good quality	Red plot: bad quality

The plot shows, for each Detection Element, the fraction of FEC boards that do not have decoding errors. A given DE is coinsidered bad if the corresponding fraction is below the horizontal dashed line. The overall plot is considered Bad if the number and position of bad DEs is such that it significantly impacts the tracking performance.

Fraction of Boards with Good Rate

[QC on EPN - plot from the last QC cycle]

Green plot: good quality	Red plot: bad quality

The plot shows, for each Detection Element, the fraction of FEC boards that have a correct hit rate. A given DE is coinsidered bad if the corresponding fraction is below the horizontal dashed line. The overall plot is considered Bad if the number and position of bad DEs is such that it significantly impacts the tracking performance.

Average Hit Rate

[QC on EPN - plot from the last QC cycle]

Green plot: good quality

The plot shows the average hit rate (in kHz) for each detection element. A given DE is coinsidered bad if the corresponding rate is below the horizontal dashed line. The overall plot is considered Bad if the number and position of bad DEs is such that it significantly impacts the tracking performance.

Average Pseudo-efficiency

[QC on EPN - plot from the last QC cycle]

Green plot: good quality	Red plot: bad quality

The plot shows the average pseudo-efficiency for each detection element. The detection efficiency is estimated from the correlation between the pre-clusters reconstructed in either cathode of each DE. A given DE is coinsidered bad if the corresponding efficiency is below the horizontal dashed line. The overall plot is considered Bad if the number and position of bad DEs is such that it significantly impacts the tracking performance.

Quality Plots - Tracking

The following plots provide an estimation of the MCH tracking quality using the output of the online event processing.

Track phi

[QC on EPN - plot integrated over the run]

Green panel: good quality	Red panel: bad quality

The plot shows the track distribution in phi. An automatic checker verifies the unifirmity of the distribution.

In case of Bad or Null quality call the MCH oncall.

Track q/pt

[QC on EPN - plot integrated over the run]

Green panel: good quality	Red panel: bad quality

The plot shows the charge over pt track distribution. An automatic checker verifies that the difference between the positive and negative tracks is below a certain thershold.

In case of Bad or Null quality call the MCH oncall.

Number of clusters per track

[QC on EPN - plot integrated over the run]

Green panel: good quality	Red panel: bad quality

The plot shows the number of clusters assicated to each track. An automatic checker verifies that the average of the distributions is between the limits represented by the vertical dashed lines.

In case of Bad or Null quality call the MCH oncall.

Clusters size per chamber

[QC on EPN - plot integrated over the run]

Green panel: good quality	Red panel: bad quality

The plot shows the clusters size per chamber. An automatic checker verifies that the cluster size in each chamber is above a threshold represented by the horizontal dashed line.

In case of Bad or Null quality call the MCH oncall.

Number of clusters per chamber

[QC on EPN - plot integrated over the run]

Green panel: good quality

The plot shows the number of clusters per chamber. An automatic checker verifies that the number of clusters for each chambes is above a threshold represented by the horizontal dashed line.

In case of Bad or Null quality call the MCH oncall.

Known issues

• In SYNTHETIC runs, MCH global quality may depend on the replay configuration

  • in p-p replay (500 kHz) : MCH run global quality is expected to be good. If quality is bad or medium, notify the on-call via a logbook entry
  • in PbPb replay : MCH run global quality is expected to be good. If quality is bad or medium, notify the on-call via a logbook entry
  • other replay settings : MCH run global quality may oscillates between good and bad. If quality is bad or medium, notify the on-call via a logbook entry

• In TECHNICAL runs, MCH global quality depends on the DCS state of MCH

  • if MCH state is READY : MCH global quality should be good. If MCH global quality is bad a notification via a logbook entry is enough.
  • if MCH state is BEAM_TUNING (BEAM_TU) or STANDBY_CONFIGURED (STDB_CO): MCH global quality is expected to be bad. Only the "Decoding errors" is expected to have a good quality; if this is not the case a notification via a logbook entry is enough.

• In COSMICS runs, the low number of tracks makes it difficult to compute the efficiency for all detection elements in each cycle. Hence oscillations between good and bad status should be expected.

  • if Bad Preclusters quality: Bad Mean Efficiency vs DE(B) and Mean Efficiency vs DE(NB) show multiple bins below threshold value. This is a known issue, no need to notify.
  • if the global quality is bad continuously for more than 1 hour, please make a notification via a logbook entry.

• FLP Infologger

  • QC plots have been disabled and will generate some errors about not-found plots that can be ignored, for instance :
    • Requested resource does not exist: ali-qcdb.cern.ch:8083/qc/MCH/QO/DecodingCheck/1709911754085/PeriodName=LHC24aa/RunNumber=548050/
    • Requested resource does not exist: ali-qcdb.cern.ch:8083/qc/MCH/QO/PreclustersCheck/1709911754085/PeriodName=LHC24aa/RunNumber=548050/
    • Requested resource does not exist: ali-qcdb.cern.ch:8083/qc/MCH/QO/DecodingCheck/1709911754085/PeriodName=LHC24aa/RunNumber=548050/