At 10:50am today, we connected a remote Picoscope to the first 4 n-sides, one end of both resistive chains, and both crystal channels to directly measure the output of the preamps without the ADC clipping at 2V.

In the parked position, we see a ~1 Hz rate on the detector with small signals in the crystal and very small signals (potentially just electronics) on the n-sides. 

At 17:15, we moved the detector close to the beam (-20 mm from the beam). With each injection, the preamps output massive signals, roughly 10 V each for a 1.8 V max input. Attached is a characteristic screenshot, with more in the ZIP file.

The flash appears to be correlated with the injection timing. The signal seems to reach a cap at 10 V, which I believe from talking to Roman is the HV bias reaching its leakage current cap. After that, the RC discharge comes back into range. Roman suggested that roughly, this RC discharge is representative of the 
signal height. The 1/e constant is around 35 us, so a saturation time of 560 us implies an signal peak of e^16 higher, ie 8.9e7 V or 1.8e7 GeV or roughly 1e7 particles. There may be some other saturation effects that mean we do not get quite this many particles, especially given only 10^5 particles are stored, but 
either way, our detectors were seeing at least 10^5 particles ever injection.

Thus, we can clearly conclude that the observed leakage currents come from radiation damage and that our detectors are fried. This is definitely a hard learnt lesson that we cannot have our detectors in for the isochronous mode...