[Halld-pid-upgrade] [New Logentry] DIRC bar-by-bar diagnostics: Fall 2019 with better calibrations

[jrsteven at jlab.org]

Logentry Text:
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Over the holiday shutdown, data from runs 71028-71228 were processed with improved DIRC timing calibrations and better timing from other detectors (thanks Sean!).  Tighter timing (|DeltaT| < 3 ns) and angle (|DeltaThetaC| < 0.02) cuts were also used for the diagnostic plots to reduce the combinatoric background as well.  The resulting diagnostic plots for the overlayed symmetric bars (above and below the beamline) are linked on DocDB https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=4298

The summary with these updated calibrations and cuts is that Bar Box #0 does not perform as poorly as originally suspected during the commissioning run.  Bar # 36 (page 13 of the linked files) still has the known issues of lower photon yield (as expected due to the box flooding in BaBar), but the remainder of the Bars # 37-47 compare well to Bars # 13-23.

We still have a long way to go to understand this, but hopefully this is some encouraging news to start the new year.

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This is a plain text email for clients that cannot display HTML.  The full logentry can be found online at https://logbooks.jlab.org/entry/3757897
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