Reports until 11:50, Thursday 10 July 2025
H1 ISC
elenna.capote@LIGO.ORG - posted 11:50, Thursday 10 July 2025 (85673)
Locking ALS instability

There appears to be an instability when locking ALS. The X arm green build up and ASC signals begin to shake as the DARM gain is ramped to 40 and then 400. This caused multiple locklosses until we held at green arms for a longer convergence time before going to locking ALS. I have attached a screenshot of the successful lock but the oscillation still occurred. Maybe the extra WFS convergence time ensures the green controls are more robust against the darm gain change. We should look into this.

Images attached to this report