= 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'''