Similar work with klog20631.
I checked the spectra of sensors on ETMY.
BF LVDT signals have larger noise at high frequencies than ITMY's, which seem similar problem that we found in ITMX GAS before (klog18789).
I also found that MNH1 and IMV3 spectra has several times larger noise than ITMY's.
In addition, there are small jumps of signals (~ 1cnt) of MNH2 though it is not appears in spectra.
They should be investigated before vacuum closing.
Figure 1 to 5 show the spectra of sensors on IP, BF, GAS, MN, IM stages, respectively (same graphs posted in klog20631).
Followings are what I noticed from the spectra.
1. all BF LVDTs of ETMY have larger noise than ITMY's at high frequencies.
2. MNH1 photosensor has larger noise than the others
3. IMV3 photosensors also have larger noise.
In addition to this, I found the strange jump of MNH2 photosensor signals in time series data (fig6).
The jump is small (~ 1cnt) and we cannot see any excess noise in spectrum.
Since the jump is very small, it is unlikely to be a problem of sensr itself but ADC problem as we faced before like klog20197 and klog19212.
Anyway, we need to investigate it.
We used spectra of REFNUM 0025 for this check.
Data were stored at /kagra/Dropbox/Measurements/VIS/SPECTRA/0/