This morning we attempted to reproduce the laser temperature corresponding to the pre-blackout configuration (26.8 °C) in order to try to recover the previous DAS rings.

After Nicola disengaged the Guardian system, I progressively increased the CO2 laser temperature.

NI set-point adjustments:

• 09:29 UTC: from 19.01 °C to 20.0 °C

• 10:01 UTC: from 20.01 °C to 21.0 °C

• 10:23 UTC: from 21.0 °C to 22.0 °C

• 11:01 UTC: from 22.0 °C to 23.0 °C

• 11:26 UTC: from 23.0 °C to 23.3 °C

• 11:34 UTC: from 23.3 °C to 23.5 °C

At around 13:40 UTC I checked the DAS rings again, but no changes were observed (see figures).

It was then decided to proceed with the replacement of the NI CO2 RF driver. Fabio and Suzanne are currently working on it.