With Hirata-san and Washimi-san.

Pictures at SR3 remedying work after O3.

• Temperature: 22.8 °C.
• Becuase there was an earthquake over the weekend I measured IM transfer fiunctions (TF) first; the system looks healthy.
• This screenshot shows the OSEM readout before the measurement of the TFs; these values are a reference of the alignment.
• We modified ballast mass as follows (see the notebook for the precise position on BF):
  • +X side: 101.754 g → 148.529 g, Delta_m = 46.775 g
  • -X side:    37.243 g →   84.236 g, Delta_m = 46.993 g
• We closed the chamber and let the system damp (over lunch).
• The OSEM and F1 LVDT readout are shown in this other screenshot.
• F1 LVDT is 406 um (aim is 461 um per klog 15322).
• In entry 16007 I wrote the aim was 416 um, but that value is wrong; the correct value is 461 um.
• The OSEMs' readouts are very similar to what they were before adding ballast mass, meaning that there was no significant change in the orientation and position of the IRM.
• I measured IM transfer functions and the system looks healthy.
• Tomorrow we will remove some mass to bring it up to around 461 um.

With Hirata-san and Washimi-san.

Summary: without actuation the F1 keystone is 18 um away from the aim (461 um) at 23.0 ºC.

Pictures at SR3 remedying work after O3.

• We removed three washers (2.007 g) from each stack of ballast masses we were working with yesterday (see album).
• With this change the F1 LVDT went to 455 um (aim is 461 um) at the temperature of the moment.
• The position of the stacks of ballast mass we modified can be seen in this diagram in the notebook.
• The initial values of the stacks of ballast masses we modified were:
  • m(+x) = 101.754 g
  • m(-x) = 37.243 g
• The final values were:
  • m(+x) = 146.918 g
  • m(-x) = 82.229 g
• The differences are
  • Dm(+x) =  45.164 g
  • Dm(-x)  =  44.986 g
  • They are only 0.178 g apart.
• In the afternoon I checked the F1 LVDT and it settled down to 443 um at 23.0 ºC, only 18 um from the aim. The keystone easily reaches 461 um with 420 counts of coil-magnet actuation.
• The current readout of the OSEMs csan be seen in this picture. and the readout before the addition of ballast mass can be found in this other picture. Comparison shows the relative position of the IRM with respect to the IM didn't not change significantly.
• The system is expected to be healthy but I will measure transfer functions tomorrow.

I update the safe.snap as following. some channels were reverted because we maintain the suspension in SAFE state.

• The TRAMP value were accepted because the value is set at larger ramp time to avoid excite some resonance.
• The OFFSET value were accepted because the value is used for SR3 work by Fabian.
• The other value were reverted because these output signal even in safe state.