I have been testing a high voltage version of the cps in the staging building for several months now. These new sensors are supposed to have something like 4x lower noise than the cps we currently use, cps noise limits table motion between about .5-10 hz. This morning I tried to test them on the HAM7 ISI this morning. The test just required disconnecting the existing satellite chassis at the chamber and connecting a new set of in air electronics outside the chamber.
I did a couple quick transfer functions to check the sensor responses made sense, then turned on the isolation loops. Loops were stable, no problems there, but I didn't get good performance data. There were a number of people working near the chamber, so it wasn't very quiet. It also didn't seem like the HV cps noise floors were as low as I've been able to get on my test stand in the staging building.
Attached plot compares individual some cps noise floors, red and green are regular sensors from some time in the middle of the night, purple and black are the lowest noise high voltage sensors from my test this morning. Unfortunately, the other 4 HV cps were the same noise or higher than the regular sensors. I didn't have a lot of time to try to poke at the new sensors. I'll try again next week, it would help if I can have it quiet around the chamber it would help, but that doesn't affect the 100hz noise.