STAR TPC Commissioning Run

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Studies of the STAR TPC FEE Noise patterns
We have used for analysis run st_pedestal_0003704_raw_0001.dat taken on 08/16/99 shortly after the end of the RHIC Commissioning Run but just before the RHIC end-of-the-run party. So the data must be fairly reliable. ;-)
Two sectors with different batches of FEE chips were selected. Sector 12 on the west side of the STAR TPC had old version of FEE chips. Sector 6 on the same side had new, improved chips installed. We studied the distributions of the RMS pedestal values calculated by DAQ. Events were provided by F. Retiere, data analysis was performed by I. Sakrejda and S. Panitkin.
Note that analysis was performed after the RHIC party. :-)
Some postscript files are provided below.

2d plots of the pedestal RMS values. Horisontal axis - pad number, vertical axis - row number.
  • (08-16-99) Distribution of the RMS values for sector 12
  • (08-16-99) Distribution of the RMS values for sector 6

    Same disributions shown as surface plots.
  • (08-16-99) Distribution of the RMS values for sector 12
  • (08-16-99) Distribution of the RMS values for sector 6

    It's clear that the new electronics installed on sector 6 have less noise than the one on sector 12.
    It's even more evident from the distributions of the RMS values in both sectors.
  • Sector 12
  • Sector 6

    Map of noisy channels
    One can introduce a cut on the value of the RMS in order to expose noisy channels.
  • Sector 6 with cut on mean RMS greater than 2
  • Sector 6 with cut on mean RMS greater than 3
    We also replot previous distributions with first and last timebucket removed. The figure shows very clean noise pattern with "wall of noise (IS)" in row 13.
  • Sector 6 with cut on mean RMS greater than 2 and cut off edge timebuckets
    Sergei Panitkin
    Last modified: Thu Aug 19 11:03:19 EDT 1999