KAGRA VIS Meeting

2015/8/5 15:00 - 17:00

First Meeting Room of NAOJ

TV conference: 133.40.2.230

SeeVogh: KAGRA VIS

Participants

Shoda, Hirata, Sekiguchi, Fujii, Tatsumi, Mark, Fabian, Akutsu, Ohishi

Discussion

iKAGRA installation

• Schedule
  • Currently in the schedule chart, 5 weeks for the in-air assembly (including cabling) + 1 week for in-air tuning is assigned.
  • Mechanical assembly and cabling will take place alternately.

  • Let me (Aso) know if you have suggestions about the schedule

  • Schedule chart: https://www.dropbox.com/s/ukanoq8s8aud6lz/iKAGRA-VIS-Installation-2015.pdf?dl=0

  • Uchiyama-san's slides http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=3866

• Installation Review
  • We should have a review meeting on the whole installation procedure of Type-Bp suspension early next week
  • Aso will circulate a Doodle poll
  • The meeting should be about glueing (Tatsumi), IM assembly (Shoda), mirror hanging (Fabian's document), and everything else (Mark).
• Payload test hanging at Mitaka
  • We may want to do it in the clean room for BF assembly.
  • Put a bread board on a table there ? Using shims to level the bread board ?
  • Spare mirror glueing will finish on 8/19. The test assembly can start on 8/24 ?

  • Shoda-san will take charge of this with help from Fabian and students.

TAMA experiment

• Current status
  • Alignment control of the prototype suspension with an optical lever was successful. But not so stable.

  • RM pitch mode around 5Hz is a problem. Could use the RM magnetic damper -> Sekiguchi-kun will try it.

  • Changing the RM wire to thin ones will reduce the resonant frequency of the pitch which makes the control even more difficult.
  • We probably need to keep using Tungsten wires (higher elestic constant).
  • We should buy Tungsten wires with several different diameters and try winding with winches to determine the thickness of the wires (thickest possible one).

  • Shoda-san will buy Tungsten wires after consulting with Takahashi-san.

Preparation status of the iKAGRA large suspensions

• Cables

  • Review of the cabling plan made by Mark should take place in this week at Mitaka.

• OSEM
  • Waiting for parts to arrive: Expected delivery Aug. 23rd. Assebly and calibration will follow. OSEMs will be ready early September.
  • Satellite box: Talking with AEL group about current limiting resistor.
  • Got a high power coil driver from AEL

Tyep-Bp temporary damper

• Simulation by Soda-san

  • http://gwwiki.icrr.u-tokyo.ac.jp/JGWwiki/KAGRA/Subgroups/VIS/TypeBp

  • Adding OSEMs on the BF to actively damp it seems the best solution

  • Need to check the required force to damp the suspension (Shoda)

  • Fixing the BF to the traverser is another option. It has performance degradation.
• Feasibility check of the modifications by Mark

  • http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=3467

  • Easiest one seems rigidly connecting the bottom filter to the traverser.
  • Adding OSEMs are relatively easy. However, moving range of the BF for alignment will be severely limited by the exisitence of the OSEMs.
  • If we use reflective photo-sensors instead of OSEM, we may be able to increase the adjustment range ?
• What to do for the temporary damper
  • Option 1: Do nothing. We may be able to lock iKAGRA with 5um/sec RMS. Need more considerations.
  • Option 2: Do the imobilization of the BF for iKAGRA. Change it to a better one for bKAGRA if necessary.
  • Option 3: Add OSEMs to the BF if we come up with a good idea to keep the adjustment range of the BF.

  • We should decide on the strategy by the next VIS meeting