Last Friday we made some noise injections in order to check the correct functioning of the SSFS and to be able to calibrate the SSFS actuator in order to complete the analysis of the state of the CMRF. We made three sets of measurements:

• INJ stand-alone, injectino on the RFC error signal -> 1211291944 / 1211292143
• INJ stand-alone, injection via the SSFS actuator -> 1211292526 / 1211292647
• CARM2MC, injection on the loop -> 1211292940 / 1211293070

The first injection confirmed that the initial UGF of the IMC loop on the RFC is ~180Hz as expected. From the last one we learnt that the UGF of CARM2MC lower than expected, ~100Hz (see Figure 1). This explains why we are obliged to increase the crossing point by a factor 2 when engaging the SSFS in order to keep the crossing point between both at the same frequency (~150Hz). Once this is understood, we will adjust the normalization and put the crossing point back to nominal when possible, so that the IMC loop UGF stays always at the same frequency.

For the calibration of the SSFS we will post tomorrow the corresponding analysis.