Ushiba, Tanaka
related to klog31986 (REFL), klog31992 (MCE TRANS)
IMC REFL optical layout is here. Optics name convention is followed as the ones in this layout as below.
## Abstract
We checked and aligned the beam path for both LSC and ASC on the IMC REFL table for incrasing the input laser power. Also, we found and dumped some ghost beams in both pathes. However, we found that the transmiited light from the lower mirror of the periscope hit on the table directly. we need to take care of the beam.
## What we did
we started the check from the upstream of beam path. We found that the transmiited light from the lower mirror of the periscope hit on the table directly (fig.1). One of the strongest beam power comes here after PSL. So we need to take care of the beam.
After that, we found that the beam position on L1 was off center in the horizontal direction (fig.2). So, we tweaked the lower mirror of the periscope, and we started the alignment of all optics in both downstream pathes. After the alignment, all of beam positions seem to be each center (photo saved in the KAGRA dropbox)
During the alignment, we found that some ghost beams were not dumped. We dumped them as possible as we can. (Fig.3: the ghost beam maybe from L1 and reflected by BS2, Fig.4: the ghost beams in the ASC path are blocked with an iris)
After the alignment, we confirmed IMC can be locked.