R&D (FilterCavity)
EleonoraCapocasa - 14:15, Saturday 27 May 2017 (478)
Filter cavity end mirror successfully installed

In the past days we worked in order to suspend the filter cavity end mirror in the end room vacuum chamber. 

As a preliminary activity we performed a major cleaning of the end room.

On Thursday 25th, we opened the vacuum chamber and removed the dummy mirror (an old TAMA PR mirror).

On Friday 26th, we installed the final filter cavity mirror (end #1 substrate)

The procedure followed to change the mirror is sketched in the attached pdf.

After the mirror substitution, we sent the beam from the central bulding to the end mirror and tried to move it with picomotrs in order to send the beam back. Unfortunately the dispalcement in yaw achievable with picomotors was not enough to allow it and we were forced to slightly turn the whole suspension. (The problem of the small yaw range was already observed for the PR telescope mirror. Also in this case we solved it by slighty moving the whole suspension). After this operation the reflected beam seems reasonably centered on the small gate window (that cannot be open utill the end chamber is evacuated).

We remark that the green beam is quite big, still too astigmatic and also moving a lot. The work in the next days will be devoted to improve it.

OTHER REMARKS

1) Picomotors for controlling pitch and yaw are working fine. They can be remotely controlled with labview (IP adress 133.140.121.15) and also locally using the joystick (pictures 2-3)

2) Thanks to Yoshizumi-san, we now have working wi-fi (naoj-open) and working phone (number 3472) in the end room!  (picture 4)

3) Dummy mirror (old TAMA PR) is currently stored in the filter cavity mirror case of substate #1 (picture 5)

Images attached to this report
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Non-image files attached to this report