The today shift was devoted to the tuning of the ITF working point.

We performed the following steps:
- 6.59 UTC: WI DAS OUT power increased. The optical gain increased but the sidebands slightly decreased;
- 7.57 UTC: Julia closed the BS control in full bandwidth;
- 8.15 UTC: WI DAS OUT power increased. The optical gain further increased up to 2070e-6 but, on the contrary, both sidebands and dark fringe became worse;
- 9.38 UTC: WI DAS IN power decreased. Optical gain stable, sidebands slightly increased;
- 11.05 UTC: NI DAS IN power decreased. Improvements in sideband level, dark fringe and sensitivity. No change in the optical gain;
- 12.01 UTC: ITF unlocked. After relock the sidebands level and the optical gain resulted to be lower for not clear reasons;
- 13.20 UTC: NI DAS IN power further decreased. 

Preliminary conclusions:
- WI DAS OUT increases (in some way) the optical gain, while WI DAS IN and NI DAS IN seem to not contribute to it;
- increasing the optical gain, we did not see any improvements in the ITF working point (brighter dark fringe, lower sidebands, no sensitivity improvement);
- by decreasing at the same time WI DAS IN and NI DAS IN the sidebands and the dark fringe improved

It is not clear why after the ITF unlock the working point of the detector changed a lot, despite of the thermal transient induced by the TCS already reached the steady state. The main changes regarded the offset of the BS TX and PR TX.

We are not able in this ITF working point to reach again the 45 Mpc, despite of the sidebands level is the same, the optical gain is higer and the dark fringe is low as before the TCS tuning. Moreover the BS is now engaged in full bandwidth. 

Julia saved the new offeset in Metatron.

In conclusion, we left the ITF in the following conditions:
- BS closed in full bandwidth;
- P WI DAS IN = 80 mW; P WI DAS OUT= 300 mW;
- P NI DAS IN =310 mW; P NI DAS OUT=2.3 W.

We will monitor the ITF behaviour in the next hours in order to acquire some data and to understand if to leave it in this configuration or restore the previous one (P WI IN=120 mW,  P WI OUT=30 mW, P NI IN=600 mW, P NI OUT=2.3 W).