Today we noticed that there were some unidentified bright dots on the ITMX green camera (cam22) which had not existed before. The positions of the dots were found to be functions of the alignment of the ITMX compensation plate for some reason. We temporarily applied a large offset (-530 urad in yaw) on the compensation plate to minimize the effect on the centroid fitting. We tried moving the dots by moving the large suspended optics, but none of them showed dependencies. We have no idea why we started having thees dots. We will try using the camera as it is since the dots seem to be insensitive to the arm cavity alignment.
- 1st attachment: cam22 view 10 days ago (Mar 11th)
- 2nd attachment: current camera view with ITMX and ETMX misaligned. Also the ITMX compensation plate is misaligned with the large offset.
- 3rd attachment: current camera view with the green light resonating as a 00 mode The ITMX compensation plate is misaligned with the large offset.
- 4th attachment: PR2 with the X green light locked as a 00 mode. The green Y beam was blocked.
- 5th attachment: PR3 with the X green light locked as a 00 mode. The green Y beam was blocked.
The compensation plates seem to be responsible for the etalon effect. The green spots disappear, when the green beam is shuttered at the end.
Updated the camera configuration files (centroid and radius) and reference positions. Attached are snapshots and the config files.
