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VIS Operations Manual - Type A Suspension

Aligning the Type-A suspension when pumping the chambers

Torsion (yaw) alignment

1. Prep for monitor channels.

   • Monitor K1:VIS-ETMY_BF_DAMP_Y_INMON using dataviewer or StripTool

   • Also, it is always a good idea to monitor the test mass optical lever whose channels names are something like K1:VIS-ETMY_TM_OPLEV_TILT_YAW_OUTPUT.

   • When looking at the optical lever, make sure that the sum is close to 50,000 counts. If smaller, this likely means that the beam fell off from the QPD.

   • For lazy persons, there is a template for StripTool:

        StripTool /users/kiwamu/templates/striptool/ETMY_oplevs.stp

2. Rotate the BF (bottom filter) using the pico motor

   • From sitemap, go to PICO. This will open the pico motor summary window.

   • In the pico motor window, click on ETMY and select Payload Yaw in the pull down tab.

   • This will open up a small pico motor window.

   • Type in the appropriate number in the STEP form.

   • Roughly speaking, 8 steps give a yaw rotation of 1 urad.

   • Click on either FWD or REV.

   • FRD rotates the BF and the payload in clockwise as seen from the top. Rev does a counter-clock wise rotation.

3. Make sure that the suspension responded by looking at the monitor channels.

4. If the suspension doesn't move, restart the pico motor script.

   • First, log in to the script machine by running

        ssh k1script -l controls

     Then check whether the script is still running or not by typing

        ps -elf | grep ETMY

     If a running process exists, kill it in order to avoid duplicated processes.

         kill aaaa

     where aaaa is the process ID number. No action is required if there is no running process. Restart the script by

          pico_start ETMY

5. If the pico_start is unable to restart the process and leaves error messages, try sending a ping to the IP address that is shown in the error message.

   • If the pico motor driver doesn't respond to the ping command. Then someone needs to go to the 2nd floor of the EY station and physically switch off and on the pico motor driver. The pico motor driver resides in the clean room of the second floor. It is a black box with a white label on it saying EYV or something similar.

Pitch alignment

1. If the amount of misalignment is small i.e., the optical lever still receives the light, one can use the marionette stage.

   • Use the test filter bank in the cryogenic payload medm screen and type in offset in the K1:VIS-ETMY_MN_TEST_Y_OFFSET.

2. Use the moving mass which is on the payload marionette stage.

   • This requires a dedicated Windows machine for now. Call an expert for it.