Run 10 TPC Anode HV QA

Analysis I: Late voltage turn-on

In this analysis, I scanned the DB for any entries which occurred between the start of a run and the minimum between the start + 5 minutes, and the end of that run.

I have initially looked at the Run 10 7 GeV, 11 GeV, and cosmic ray run periods, spanning essentially days 112 through 159.

I found that this happened on the "whole TPC" scale about 20 times over the course of these running periods. It also happened on the individual channel scale about 120 times. These can be seen in the following plot of anode voltage channel (sector + channel/10, e.g. 21.3 is sector 23, channel 1) versus time in seconds (with an arbitrary time offset):

The vertical lines visualize the "whole TPC" occurrences, which looks dashed because there are only 8 channel per sector. This plot obviates particularly troublesome channels in sectors 5 (channels 5,6,8) and 6 (channels 6,7,8), seen even more clearly by projecting to the vertical axis:

During this process, I also saw about 180 occurrences of individual channels where the voltage was listed as "on" at the start of the run, but went to 0 in the first 5 minutes. There were 4 instances of the very large fractions of the TPC going to 0 in the first 5 minutes. I think a couple of these are trips of the TPC, but I know at least 1 of them is not. These drops to 0 need more investigation.

-Gene