Daniel, Nutsinee
Attached a RIN plot of various detectors on ISCT6 table. The blue plot is the intensity noise measured off the laser monitor diode. By the time we get to SHG trans PD the noise is worsen by a factor of 10 at ~2-3kHz. The factor of two difference between SHG trans (red) and the green PDs is due to red->green conversion. Question is, this is what we saw in the IFO squeezing attempt in alog45767 ? To be sure that switching scheme helps we need the same intensity noise data from LLO to compare. If LLO intensity noise is not as bad as ours switching scheme may not solve the problem.
Terry, Sheila
We looked at coherence between DARM when we had injected squeezing on Friday night, with intensity noise on a few of the diodes which are recorded at 2kHz. (OPO REFL, SHG trans, and CLF refl). We don't see any coherence with intensity noise and DARM.
We also looked at the additive offset channel which was used to detune the OPO from resonance, and we don't see any coherence with DARM.
We wouldn't expect a linear coupling from either of these things to DARM in the first place, unless we have a bad seeding problem, but this was just a check. We will work on setting up a diode to test for seeding.
