20181109
Today's activities
Workers: Akutsu, Yano, Simon, K. Tanaka; Observer from CAL: Darkhan
- Pulled up the whole payload (NAB suspension with PD holders + inner tower) by the chain block connected to the crane, and inserted into the IYA.
- Operated the chain block on a ladder step to access the chain to be operated. This is because (1) we did not like to use the brute (or too sensitive) crane for pulling up the payload, and (2) considering the lifting height required to come over the chamber's upper flange, the chain block should be located at some height with the crane hook.
- Attached 3-m slings, which we borrowed from Hirata-san, on the both sides of the inner tower's lower beams to handle/damp the payload. One person for each handles to damp the dancing of the payload during the crane working, especially the transverse moving.
- Pulled down the payload with also the chain block. And then the four feet of the inner tower can gently touch the top surface of the breadboard in the IYA chamber.
- Aligned the whole payload.
- Akutsu entered the IYA chamber to manage and push/pull the whole payload so that it can stand at the "designed" position and alignement. Two workers were supporting the alignment with/without the sling handles.
- It seemed some white tapes on the breadboard would indicate the original position of the inner tower, but there was an inconsistency; the request from CAL (via Kozakai-san) was 10cm shift to Yarm side, but the white tape would indicate it was 5cm shift... anyway, we put it at 10cm shift in the Yarm directoin.
- At the same time, a laser level was brought in the chamber, and aligned the laser beam to a line indicated on the white tape on the breadboard. Akutsu checked and managed the horizontal centering of the NAB itself by the eyeballs and feelings; there are no good indications on the NAB itself.
- This time we could use the chain block, so the alignment works and the re-works were not more difficult than those at IXA... but...
- Blanced the inner tower and roughly fixed.
- By putting bubble levels on the top parts of the NAB suspension, we checked the balance (horizontalness) of the whole payload in the pitch and roll. Yaw was... we just used the aligness of the screw holes on the breadboard and the edges of the feet of the inner tower.
- Inserted several shims under the feet of the inner tower so that the bubble levels got nice. A jack was used to make space for the shims.
- Tried to fix the feet and shims, but unfortunately the design of the clamps were not suitable to fix the situation. We need more sophisticated resolution...
Next Plan
- Fix the inner tower more seriously.
- Do some sanity checks.
- Vertical centering?
- Measure the resonant frequencies and the Q-factors with laser displacement sensors?? and oplevs?
- Take interface with the work for recovery of the TCam.
Wanted!
- Clamps for the inner tower...