Eleonora, Xinghui

Today we shaked the OFI suspension in the longitudinal direction by leaving the OSEM2EULER matrix to [ 1 0 0, 0 1 0, 0 0 1 ] and setting the EULER2OSEM matrix to [ 0 0 0, 0 0 0, 1 0 0 ]. We tried to send a signal also on RT to balance for YAW, but it turned out that it was not better. The residual coupling is 6% between SD (side = longitudinal) and LF (transverse left) and 3% between SD (side = longitudinal) and RT (transverse right). This is good enough for our measurement.

We took clean data between 00h50 UTC 23 April 2023 for 10 mins without squeezing.

We injected a sine noise in the OFI longitudinal suspension at 0.65 Hz and gain = 10000 which corresponds to a motion in LF = 0.72 um, RT = 0.33 um, SD = 11.3 um at 1h10m00 UTC for 10 mins.

In Fig. 1, the scattered light noise shelf is shown in blue (we can see both the first and second orders) and the reference in magenta.

We tried to inject more noise, with a gain of 12000, but the interferometer unlocked.