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Reports until 23:55, Monday 04 November 2019
H1 TCS (DetChar)
daniel.brown@LIGO.ORG - posted 23:55, Monday 04 November 2019 - last comment - 01:49, Tuesday 05 November 2019(52989)
Phase camera overheating, powerup + CO2X test round 2

In the movie linked in alog 52927 we saw the phase camera begining to fail in a way we hadn't seen before, around 35s into the movie. We ran it again during throughout the lock acquisition today and it lasted much longer into the lock however it started to happen again. It seems the resonant circuit used to drive the pockel cell has reached some temperature limit after prolonged use. When we reduce the driving voltage by half we start seeing the same images as we did before, except with 50% reduction in amplitude. Leaving it to cool down also seems to fix the problem for the first few images but the it starts up quickly again. Something to be fixed in the next version.

We also wanted to try the CO2X test again (agreed with Keita) where we drop CO2X and then raise it up again to see how the carrier+sideband mode matching changes. The change will be small +-100mW left over an hour. Short jumps out and back into observing will be required, I'll comment GPS times when we start.

However we just had yet another GRB event so we're standing down again, hopefully can try this later.

Comments related to this report
daniel.brown@LIGO.ORG - 00:24, Tuesday 05 November 2019 (52992)DetChar

Starting: 1256977145

Seems the CO2 powers aren't actually tracked by the SDF, so I won't drop out of observe next time.

daniel.brown@LIGO.ORG - 01:49, Tuesday 05 November 2019 (52995)

Finished up at 1256982152. Went back to nominal CO2X setting as DHARD P 0.6Hz started to get angry.

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