R&D (FilterCavity)
MarcEisenmann - 15:42, Wednesday 24 August 2022 (3052)
FC lock issues

Marc, Yuhang

We have to reload DDS2 config everytime to be able to lock.

Then we are looking at the GR_corr spectrum to investigate the driving matrix of the INPUT but we found out that the noise level is not stable at all (see figure 1).

Our reference level is in blue with injected line on INPUT_PIT_ex2 at 5 Hz and 5000 amplitude is blue curve of figure 1.

At other times, we can see noise increase up to 10 Hz or even at higher frequency.

This is true with or without line injected, with or without AA or pointing loop.

Same after restarting laser.

Not affected by closing AA or pointing loops.

After some time, the noise excess disappeared and we could start some measurements but it quickly reappeared again..

PIT_ex2 4500, GR_corr 7.52

4000, 6.70

3500, 6.47

3000, 5.97

2500, 5.38

Images attached to this report
3052_20220824074446_20220823grcorrnoise2.png