camilla.compton@LIGO.ORG - posted 10:19, Tuesday 05 December 2023 - last comment - 12:31, Tuesday 05 December 2023(74602)
New MICHFF FM8 did not cause a lockloss
This morning we tried Gabriele's new FM8 MICHFF filter with more low frequency gain. It did not cause a lockloss. Not enough time in this configuration to see the effect on DARM, see 74595. We can repeat this during a commissioning period.
In addition to Camilla's trend shown in 74595, we can see that the new MICHFF, despite having a large MICHFF_OUT, does not change the low frequency RMS of the DARM error signal.
This allows us to relax a bit the aggressive roll-off we had in MICHFF fits below 10 Hz.