Kiwamu, Jenne, Alexa, Sheila, Daniel,
Today we locked ALS COMM. We chaanged the locking sequence compared to our old sequence. One difference is that we have moved the notches in MC2 to M2, so we can have a higher crossover between the slow and fast actuators (CARM gain is 240 now, instead of 80). We also got rid of a z5 p20 filter we had in the CARM filter module. The rest is the same as it was in late May. This seems to be locking fairly robustly. The ugf is 1 kHz, with a phase of -80 deg. A measurement of the cross over is attached.
We also aligned the DIFF beatnote, 800mVpp. We have locked this at low gain a few times. We need to feedback to the top mass of the ETMs to keep the DIFF PLL within the VCO range, but we have had trouble engaging the tidal feed back.