Today we have checked the green lock after the installation of the source in the EIB bench. The motivation of this action was to reduce the amount of fiber used in the propagation of the green, since the air conditioning in the Laser Lab was producing noise that was strongly polluting the error signals.

We first aligned the west arm and locked the infrared without major problems. Then we locked the green in reflection of the west arm, which locked without major problems as well. At this point we checked the signals seen by the PDs in teh central building (ALS CEB WARM BEAT 154MHz). There is no saturation, we have slightly improved the "mag", and the spectrum of the error signal that we used (_dFreq) has improved a lot at high frequencies where we were dominated by the air conditioning noise (see Figure 1). The rms has improved by a factor 4 (our-of-loop).

We will have to wait to have both arms to check the passage to CARM/DARM but the target will be to increase the UGF of these loops. In order to check that we are no longer limited by the ambient noise we will make a test of turning off the air conditioning.