Reports until 16:46, Tuesday 10 March 2026
H1 IOO (IOO)
jennifer.wright@LIGO.ORG - posted 16:46, Tuesday 10 March 2026 (89461)
IM1 and 2 today compared to December 12th

Jennie W, Jenne D

 

We need to check the positions of IM1 and 2 as we have now closed all 3 loops for the IMC alignment.

Jenne was windering how our input alignment to the IFI compares to before the vent.

We compared the IM 1 and 2 pitch and yaw positions in manual initial alignment between today and the 12th of December - when we were doing our last locking before the vent.

This comparison is during manual initial alignment which is state 8 in the ISC_LOCK guardian.

The first pic is the 12th December, reference time is 05:21:30 UTC.

The second pic shows today with y cursors at the reference values. The biggest difference is IM2 pitch which is ~120 counts lowewr than it was, the other 2 DOFs are tens of counts off.

I also included IM3 and 4 in my plots but I think we have intentionally changed IM3 since the vent to improve alignment onto IM4 trans and IM4 is controlled.

Images attached to this report