From run st_physics_1175046_raw_0001.daq. This run was taken on Fri Jun 23 23:17:48 2000. Trigger word 0x1, Trigger Input word 0x4023, Detectors present: TPC SVT RICH. The magnet was at 0.25T and the beam was at gamm=70 GeV.
I haven't made any attempt to not count hits in this data but I think there
are few enough of them that it doesn't affect the result. The results from
40 events are in these plots. Shown below are the mean and rms of the ADC
Fig 1. Mean ADC counts for Wafer 4 and 5
Fig 2. RMS of the ADC counts for Wafer 4 and 5
Fig 3. Mean ADC counts for Wafer 6 and 7
Fig 4. RMS of the ADC counts for Wafer 6 and 7
It seems that the noise doesn't get worse with the field and beam there.
Wafer 6 hybrid 2 seems bad.
Too see if the noise on the wafers got worse from being in the beam I then looked at Run 1234037 which was taken on Aug 21st. You can see that things look around the same.
Fig 5. RMS of the ADC counts for Wafer 4 and 5
Fig 6. RMS of the ADC counts for Wafer 6 and 7
By this point in the run we had added the E side of the readout so here are the RMS plots for Wafers 1,2 and 3. Don't be fooled by the apparent drop in noise the East readout had a different mv/ADC conversion than the West. So in actual fact I think the noise is a bit higher (from my memory that the donversion factors were difference by a factor of two.)
Fig 7. RMS of the ADC counts for Wafer 1 and 2
Fig 8. RMS of the ADC counts for Wafer 3
Helen L. Caines
Last modified: Fri Sep 22 17:52:40 EDT 2000