Virgo Logbook

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Injection system (General activities)

pillant, genin, de rossi, magazzu, boschi, carbognani, vacuum team - 18:42 Thursday 22 February 2018 (40665)

beam alignment towards the ITF recovered

After the issue reported in the entry #40650, we open the tower today.

Once entered in the INJ tower we found as expected the M1 mount strongly tilted (see attached pictures).

The IB was controled as PR in the last known good position (02/02/2018). Using an Half wave plate we bypass the IMC and

using an other one on the IB we recover the right polarization before the faraday isolator.

Using the faulty picomotor we were able to recover the B2 beam reflected by the PR. The picomotor was moved by about

30.000 steps which is corresponding to a tilt of about 11 mrad position (from -1920 to -30627) !

From the software side, no movements are identified in the logfile...

We will report the reason of the problem once understood.

NB : it seems the "chiocciolone" of the INJ suspension doesn't work, to be checked by SAT asap.

Images attached to this report

Comments to this report:

genin, derossi, ballardin, pillant, pasqualetti, casanueva - 12:07 Friday 02 March 2018 (40704)

After the injection system relock the IB to PR flanges have been opened by Antonio.

The PR has been put in the last reference aligned position. M1_TY has been moved by 200 steps backward (-30827 is the final absolute position of the motor).

As you can see on the attached picture. The beam arrives again on B2 cam.

NB: the ethernet cable at the level of the closed loop picomotors was not well inserted in the plug. We were able to start the server.

After plugging the cable properly it has been possible to start the server and move the motor.

Images attached to this comment