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AdV-TCS (CO2 laser projector)

cifaldi, menzione - 8:55 Wednesday 30 October 2024 (65431)

WI DAS INNER RING power increase

As planned, this morning the WI DAS INNER RING power was increased from 150 mW to 300 mW.
The power change was completed at 07.45 UTC with the ITF in adjusting mode.

The powers injected into the ITF are summarized in the table below. The new WI DAS inner ring power values are in bold.

	Reference	INNER DAS [W]	OUTER DAS [W]
W	on the ITF	0.154→ 0.300	1.596
W	on the pickoff	0.025→0.049	0.260
N	on the ITF	0.340	3.68
N	on the pickoff	0.055	0.613

Comments to this report:

cifaldi - 12:17 Wednesday 30 October 2024 (65432)

After about 2 hours from the DAS step (thermalization time is completed), before the lock acquisition test, I checked the CO2 powers and restored the nominal values as listed in the table. The check was performed between 10:40 and 11:00 UTC.

mwas - 8:38 Monday 09 December 2024 (65748)

Figure 1. Since the increase in WI DAS inner ring power the MICH offset has been higher in steady state, and the SRCL offset lower. There hasn't been any noticeable change in frequency noise coupling.

Figure 2. Looking directly at the B4 56MHz photodiode signals the transition is more clear, the magnitude of the offset has not changed, but the phase has a clear step, with a clear change in the ratio between the I and Q quadrature.

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