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VIS (SRM)
fabian.arellano - 22:16 Wednesday 09 June 2021 (17033) Print this report
Lowering the pre-isolator.

With Hirata=san and Washimi-san.

 

  • Temperature T = 22.8 °C (O3GK T = 22.9 °).
  • We set the GAS filters to zero:
    • F0: we locked it at zero becuase the FR does not reach zero (the amount of ballast mass must be adjusted).
    • F1: we used 10,000 counts of coil-magnet actuation.
    • BF: we used -4,000 counts of coil-magnet actuation.
  • We measured the height of the mirror: 0.85 mm.
  • Using the jacks that have a M42 X 2 mm, we lowered the pre-isolator by approximately 0.875 mm (in steps of 0.5+0.250+0.15 mm).
  • We measured the height again: the mirror was 0.3 mm above the nominal position (per Terada-san's mark) when the GAS filters are in zero. Given the thickness of the laser level (approx. 2 mm), 0.3 mm is acceptable.
  • Then we finely tuned the tilt of the IP to have L and T close to zero. 
Comments to this report:
fabian.arellano - 17:18 Thursday 21 October 2021 (18649) Print this report

With Hirata-san.

Summary: the mirror (RM) is 2.8 mm below the expected height of the beam when the GAS filters are at the setpoints.

See pictures in SRM Remedying Work album.

  • Temperature T_PT100 = 22.9 °C , T_ondotori = 22.9 °C (O3GK T_ondotori = 22.9 °).
  • We set the GAS filters to zero:
    • F0: we used the FR but it reached its lower limit, then we used -7,500 counts of coil-magnet actuator.
    • F1: we used -13,650 counts of coil-magnet actuation.
    • BF: we used -4,450 counts of coil-magnet actuation.
  • Then we measured the height of the RM with respect to Tomaru-san's making of the expected beam height pasted either yesterday or today.
  • The RM is 2.8 mm below the reference.
Images attached to this comment
fabian.arellano - 16:07 Wednesday 27 October 2021 (18704) Print this report

With Hirata-san, Terrence and Yano-san.

Summary: we raised the pre-isolator in order to have the mirror (RM) at the expected beam height when the GAS filters are at their nominal positions (zero). 

See pictures in SRM Remedying Work album.

  • Temperature T_PT100 = 23.2 °C , T_ondotori = 23.0 °C (O3GK T_ondotori = 22.9 °).
  • We set the GAS filters to approximately zero with coil magnet actuation:
    • F0: 1,500 cnt,
    • F1: -8,400 cnt,
    • BF: -2,000 cnt.
  • According to entry  18649, the mirror was 2.8 mm below the expected beam height, therefore, we raised the jacks (M42 X 2mm thread) by rotating them counterclockwise 1.4 turns approximately.
  • We measured the mirror to be at the correct height (at zero with respect to the reference, see this notes).
  • Then we adjusted the tilt of the IP:
    • L: -201 um (setpoint -550 um),
    • T: -100 um (setpoint -50 um) .
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