Since Jan 1st, after the problem on the PSL/INJ subsystem , we have less power generated at the output of the Neovan amplifier (see fig. 1).
This implies that the pickoff of the input beam used by other subsystem is lower than before (see fig.1 the ALS_CEB pickoff).
To be noted that, even if the AMP power reduction is ~10%, the pickoff seems lower by ~20%.
If needed, the pickoff power can be increased by using the apposite IPC on the laser bench.
This morning we repotimized the injection in the pickoff fiber (see attached plot).
After the work of yesterday morning on the neoVAN amplifier, the pickoff for ALS et al. has in principle changed power by more than 10%.
However, looking at the ALS seed in the Atrium (fig. 1), the power seems to be the same as before, but with increased noise. Since we modified the alignment into the neoVAN, there could be also a misalignment of the beam injected into the fiber.
