Reports until 10:04, Friday 19 September 2025
H1 ISC
sheila.dwyer@LIGO.ORG - posted 10:04, Friday 19 September 2025 (87022)
ALS path on ISCT1 powers

The ALS COMM beatnote is reduced by about 3dB (was -4 dBm before power outage, is now -7dBm).  This is probably OK, our past experience was that we start to have trouble with ALS when the ground motion is high and the beatnote is about -15dBm. 

The attached screenshot shows the power arriving on ISCT1 can explain this, the first cursor is the power outage time and the second cursor is when the power through the EOM was reduced 86966

Images attached to this report