Since the last SL Temp controller failure, the beam alignment into the neoVAN amplifier slightly drifted (fig. 1). As a results, the AMP_DC decreased and the alignment into the AOM and the PMC started to worsen constantly.

In agreemend with Walid and Michal, we decided to touch again at the alignment on the laser bench during the maintenance of yesterday.

As we did at the beginning of the year, I started by improving the matching into the amp head in order to get back most of the power at the output of the amplifier, and then work on the alignment at the entrance of the AOM, looking at the HOMs in reflection of the PMC (in scan).

At the end of the work, I could recover almost the original power on AMP_DC and highly improved the matching into the PMC. The effect is clearly visible on the PSTAB correction (fig. 2), where we gained almost a factor of three.

However, for matter of time, I didn't inspected deeply the beam all along the path. We will check in the following days if the stability of this new alignment.