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Since we may wish to incorporate some kind of baseline calibration/monitoring during the upcoming 2021 run, it was decided to investigate whether this could be done as part of the online Data Quality Management (DQM). This would involve filling the requisite histograms as part of the DQM stream and fitting the plots as part of the endOfData() method. Depending on the memory requirements, this could be accomplished as part of the normal DQM processing, or could be split off into a separate process.

Status

A prototype Driver has been written and a subset of run 10648 has been processed.

Analysis Discussion

During the data-accumulation phase, a 2D histogram is created for each sensor. The x axis corresponds to the strip / readout channel number and the y axis contains the value of the first of the six APV25 readout channels. The split-strip thin sensors in layers one and two contain 512 strips, while the remaining sensors have 640 strips.

During the endOfData() phase, every y slice of each histogram is analyzed. If there are sufficient entries in the slice a peak-finding algorithm is run to identify the baseline peak. If the peak structure is well-behaved a Gaussian function is fit to the bins in the peak. If this algorithm fails, a second algorithm is run to handle special cases. The results are then plotted and the next slice / histogram is processed.

Status

A prototype Driver has been written, histograms have been created for all 295 "good" runs, and run 10648 has been processed in order to compare with the earlier analysis.

Results

The output histograms with their fits can be found in this pdf file. The plots fall into five categories:

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