This afternoon we carried on the recovery of the injection system.
We could relock the IMC but it was very difficult to find a good alignment because of the appearence of high order modes. We had to displace the beam horizontally on the end mirror to get away from these resonances.
In this new "good" position some loop oscillations at 187kHz occured and they were killed by further attenuation of the IMC error signal by 4 dB. We do not know the cause but one check we could do is to better tune the 22 MHz demodulation phase.
Once this oscillation was killed, we measured the new automatic alignment sensing matrix. However, as soon as we closed the alignment in drift control, the BsX X CORR (which are closed on IMC QD FF I H) drifted away. We should also check the demodulation phase of the quadrants for the automatic alignment (in particular FF).
MC ty gps = 1352835395.00
IB ty gps = 1352835057.00
MC tx gps = 1352835302.00
IB tx gps = 1352834886.00
IB tz gps = 1352835177.00
We also encoutered problems in closing the PSTAB loop, but this is probably induced by an oscillation on the IMC itself (to be confirmed).