As planned, this morning at 5.50 UTC, the ETM RH powers have been changed with the iTF in 'adjusting'.
The old and new values are summarized below:
| STEP 1: RH power change | NE | WE |
| +100 mW on the NE -100 mW on the WE | 6.9→7.0 W [16.04→ 16.14 V] | 8.4 → 8.3 W [17.67 → 17.57 V] |
Figure 1 There has been no visible impact from the RH step on the amount of DARM signal on B1s (OMC rejection port demodulated at 491.3Hz).
Figure 2 There was much more oscillation on the B1s DARM signal, and this might be due to the etalon effect which after the longer maintenance and the few hours of measurement on Tuesday afternoon was oscillating more.
The impact of Etalon on B1s DARM line is clearly visible on data from the last week of April, when the Etalon had larger oscillations.
The ETM RH differential step had a small effect to lower the B1p power, which partly compensated the increase after the last Etalon step. No effect is visible on the SSFS coupling to Hrec at low frequency.
