The following report has been submitted to the On-call interface.

On-call events -> Interferometer Sensing & Control

Title: B1p beam outside the camera

Author(s): casanueva

Details:

Tonight I was called by the operator, following the instructions of the SUSP SSM. Allegedly the marionetta values of the SR mirror were outside the usual values and I was contacted to put the SR back to its nominal position, since the beam was almost completely outside of the B1p camera. Since I was already awake, I took a look to the trend data of the marionetta values of the SR, even if this is not a specific ISC task. I checked the "misaligned" values of the last lock, but it looked to me that the SR was int he right position (within 2urad), and so this couldn't be the reason for such a displaced beam in the camera (when in nominal conditions we can misalign the SR by 10s urads and we still see the complete beam in the camera).

So I profited and I tried to take a look to the position of the SR mirror in vertical and horizontal. it looked to me that vertically the mirror was in a different position (around 40ums), so this could explain why the beam was so out while the marionetta was still showing the same values as usual. see Figure 1. The SR_Vert flag in the DMS was also red, showing some excursion in the vertical position of the SR. However, I am not familiar with the SR DSP card, so I didn't feel like moving it myself. I asked the operator to contact the SUSP on-call to give a hand with it and to call me after if this didn't solve the problem.

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