Robert, Sheila, Nutsinee

Better alogs will be coming with details, but earlier this evening we spent some time doing squeezing tests.  From about 20:50 UTC to 23:50 UTC (including time when IFO unlocked and was relocked), Nutsinee did measurements of squeezing and anti-squeezing for three different nonlinear gains.  

From 23:50 UTC Dick went into the CER to do a couple of tests, the IFO lost lock during this time.  

After relocking Robert and I did some test of the acoustic coupling from ISCT6.  Robert has more details, but some main points are:

• The coupling goes away when the squeezer beam diverter is closed
• The level of the coupling is higher for anti-squeezing than squeezing
• Increasing the gain of the CLF loop can reduce the coupling
• Changing the CLF power and keeping the UGF roughly the same does not change the coupling
• Changing the LO loop gain doesn't seem to change the coupling
• Changing the OPO loop gain doesn't seem to change the coupling
• Lastly we reduced the green power into the fiber from 20mW to 10mW we reduced the nonlinear gain from about 2.4 to 1.8, which only had a small impact on the acoustic coupling when anti-squeezing.  We scaled the OPO length servo gain, but not the gain of the other loops. 

We attempted to do the measurement where we offset the squeezer laser frequency from the PSL to see the two lumps in darm from backscatter and seeding.  The squeezer laser is moving too much relative the the PSL to do this measurement.  We could probably make this better by implementing the IMC VCO FF, or if we used a pick off that isn't in the ref cav path as they do at LLO we wouldn't have as much motion.