Jeff, Kiwamu,

In addition to the classic free-swing-Michelson technique, we did another calibration of the ETM responses using the ALS diff VCO.

We locked ALS diff and drove various stages of ETMs. The plan is to take out the loop suppression by using a measured open loop transfer function and calibrate data into meters through the known VCO calibration. The data and results will come later. A conclusion from todays's calibration is that the calibration of the ETMY ESD in the low voltage configuration is difficult to measure since the strength is so weak. So for the reason, we ended up measuring only the ETMY L2 stage and ETMX L3 stage. Sigh. In order to get a reliable calibration on ETMY ESD, we probably need the DARM loop closed in fully locked interferometer and need to make a comparison between well-calibrated ETMX ESD and ETMY ESD.