Reports until 17:14, Saturday 09 March 2024
H1 ISC
trent.gayer@LIGO.ORG - posted 17:14, Saturday 09 March 2024 - last comment - 17:42, Saturday 09 March 2024(76233)
Locking the Y-arm

Georgia, Trent, Elenna

We lost lock on the interferometer (most likely from 50mph gusts of wind) and had to align the arms. The y-arm proved difficult and we could not get the flashes on ALS-C_TRY_A_LF_OUT_DQ above 0.6 counts. To help the arm along in locking we changed the pdh auto-locker threshold to 0.55. We then decided to run an initial alignment.

During the initial alignment we got red dust warnings for the corner station.

After the intial alignment, the y-arm green flashes reaches 0.73 and we didn't need to change the pdh auto-locker again.

Comments related to this report
craig.cahillane@LIGO.ORG - 17:42, Saturday 09 March 2024 (76234)
Some screenshots and parameters from our 20 hour first lock back at NLN prior to O4b!


BNS range: 140 Mpc
Arm power: 370 kW
Input power on PRM: 54.5 W
PRG: 52.5
REFL A LF: 6.8 mW
Images attached to this comment