Reports until 11:57, Tuesday 16 July 2024
H1 ISC
camilla.compton@LIGO.ORG - posted 11:57, Tuesday 16 July 2024 (79167)
OFI Temperature Control 4x larger than nominal during power up

As looked at in 79117 and 78399. the OFI's temperature control changes as we power up.

In a nominal lock before this alignment change, VOLTAGEBACK changes 0.0091V and the temperature wobbles 0.0031 degC: plot.

In today's power up at the new alignment, VOLTAGEBACK changes 0.0267V and the temperature wobbles 0.0135 degC: plot. This is 3 to 4.5 times larger than usual and larger than the changes we saw May 28th/29th 78442 power-ups: 0.0458V and 0.0097degC plot.

Note that we don't understand if this is damaging at all but it makes us think that we are closer to clipping the OFI or have the beam spot in a different position in relation to the TEC/thermistor: TEC is on bottom of the OFI TGG holder (OMC side): G1902217 slide 22. Unsure location of thermistor.

Images attached to this report