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Reports until 18:05, Tuesday 27 April 2021
H1 AOS
georgia.mansell@LIGO.ORG - posted 18:05, Tuesday 27 April 2021 - last comment - 23:18, Tuesday 27 April 2021(58765)
Started ETMX ring heater test

For Hartmann wavefront sensor characterization. Will be done in 1 hour (@ 1303610698)

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georgia.mansell@LIGO.ORG - 20:05, Tuesday 27 April 2021 (58766)
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We lost lock part way through this test. While we were down I tried pico'ing HWS EY to see if I could remove the spot from ITMY.

While I look at the ring heater data from EX I'm starting a ring heater test for EY.

georgia.mansell@LIGO.ORG - 23:18, Tuesday 27 April 2021 (58767)
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  • I tried fiddling with the dead pixel removal scripts for HWS ETMX, but didn't manage to remove all the dead pixels. I'm not sure how the script is missing them. I tried running the script with the HWS light source on, and a high threshold, but this didn't work. I also tried different thresholds and number of images to average over. During those investigations I tried displaying the dead pixel map over the Hartmann image using the HWS_live GUI, and got an error. I had to add to a line in HWS_LIGO_utilities.py (see first attachment), on line 422 I added the encoding='latin1'. The script I modified lives at /opt/rtcds/userapps/release/tcs/common/scripts/hws_tools/
  • After a lockloss I spent some time looking at HWS ETMY - which is contaminated with a reflection off ITMY. I pico'd the Hartmann mirrors to try and minimise the beam reflected off ITMY. Second attachment shows the jump in spherical power measured by the ETMY HWS when ITMY suspection goes from misaligned to aligned. The jump is smaller but there is an offset in the spherical power. The beam is still pretty well cenetered on the camera. Pico values are listed below:
      (X,Y) before (X,Y) after
    Pico #5 (HWS M2) 100, 0 170, -90
    Pico #6 (HWS M1A) 1300, -1600 1250, -1510
  • I then ran ring heater tests on both ETMs, see third attachment for times and HWS spherical powers. We should se a nice clean signal in the spherical powers, but they are just noisy and mostly flat.
  • Fourth attachment shows ETMX HWS contours during the ring heater test, there are some features in the bottom right of the Hartmann beam - maybe it is misaligned on the test mass?
  • Fifth attachment shows ETMY HWS contours during the ring heater test. There's some contours in the middle, but I think the optical density is less than we'd expect (?). ITMY was aligned during the whole test.

 

Long story short: I'm not sure these HWSs will be useful in time for tomorrow's scheduled powerup.

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