Yesterday morning, I took some time (with approval, WP5563) after LLO went down for maintence before our maintence period started. Since nutsinee had just gotten the IFO locked when I arrived, I asked her to pause and went through noise tunnings without turning off the EX ESD.
I went through different configurations with the EX ESD and took long spectra in each configuration. The bottom line is there was no change in the DARM spectra between these configurations. The attached screenshot shows (nearly identical) spectra with the EX ESD:
- High voltage mode with bias ramped down, (14:56:15 UTC Dec15th),
- in low voltage mode (LP on, HV off, HV disconnect) still with no bias (15:09:22 UTC)
- low voltage mode, linearization off bias ramped back to -9.5 V (15:17:09 UTC Dec 15th)
- turned off, as guardian normally does (Dec 16th, 15:21:21 UTC)
Since we had believed that turning off the ESD helped reduce our noise, one could be skeptical that I actually had the ESD on. The second screenshot shows the current mons, which do show current when I attempted to actuate on EX, which I think means that the driver was on.
