Series 07161105_1616 was a noise data series taken with the HV set to +60V without overshooting (“pre-biasing”). The following plots show how the noise developed over time:

Side1 pA and pD were noted as particularly noisy (pA is known to be noisier due to the HV board design because this channel crosses between two ground planes).

The PSDs were generated with Matt F's code with a rather rough rejection of traces containing pulses or muon tails.

The noise seems to be smaller in the first minute or two, probably because in this time the current drawn from the HV supply is decreasing from its initial high value, so that the actual detector bias is increasing to its final value. After that the noise peaks, then falls off to a minimum after about 12 minutes.