I was call for a problem on green production for north arm.
While investigating, i noticed that at some point between 16:00 and 22:00 UTC the 12th of November, something happened which decreased the beating DC level for both arms.
We realigned the beatings inside CEB using the VPM, recovering enough signal to allow ALS to operate and succesfully passed ALS stage and locked at around 15:30.
The green production problem for north arm is still present and is currently under investigation.
The attached plot show the effect of the BPC alignment performed on the NARM and WARM beating beams
We went at the NEB to check the status of the infrared seed.
We checked the temperature of the PPLN crystal and the setpoint was already optimal (116.4C).
We opened the PSTAB loop (14:59:46 UTC) and moved the fiber in input of the SOA (15:00:10 UTC): the IR power increased but it was very noisy. Since this kind of noise is typically produced by the 2W amplifier, we modified the setpoint from 32dB to 32.2dB (15:02:39 UTC) and the noise suddenly disappeared (see fig 1).
