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Reports until 16:20, Tuesday 22 March 2016
H1 TCS
nutsinee.kijbunchoo@LIGO.ORG - posted 16:20, Tuesday 22 March 2016 - last comment - 19:06, Tuesday 22 March 2016(26195)
CO2 rotation stage random walk measurement

Kiwamu, Nutsinee

In order to understand the characteristic of the COY rotation stage I ran Kiwamu's script with TCS CO2 channels asking the rotation stage to turn to random angles. The result is attached below. The first plot shows that CO2Y rotation stage works 85%-93% of the time (out of 300 samples). Changing the rotational state speed by 50% didn't make much difference (if not worse). The nominal speed is 100%. When the rotation stage didn't go to the requested angle the difference is always roughly 30 degree. In comparison I attached the second plot showing data from CO2X rotation stage that has quite a nice behavior. The requested angles and measured angles agree within half a degree (out of 100 samples). 

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patrick.thomas@LIGO.ORG - 17:12, Tuesday 22 March 2016 (26199)
It might be interesting to see the measured power for each of these as well. I would probably trust that more as an indication of the measured angle than the reading from the stage.
nutsinee.kijbunchoo@LIGO.ORG - 19:06, Tuesday 22 March 2016 (26203)

Below you will find the plot measured CO2 power vs. requested angle. Notice that CO2X power follows the sinusoidal pattern quite nicely while CO2Y power is ~30 degree phase delay from the main sine wave when the rotation state is busted.

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