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 * Put a report here
 * I'm working on designs(design of PCB and chassis design).
    * Main board for WDS(To reduce the size.) 100mm-150mm --> 75mm-150mm.
    * 19-inch rack 1U(height)(design of Placement in the case).

Agenda/Minutes of the VIS Meeting on 2016/12/16

2016/12/16 13:30 -

Participants: Takahashi, Hirata, Tanaka, Ishizaki, Shoda, Mark, Fabian, Enzo, Okutomi, Aso, Fujii, Raffaele, Enzo

Progress report

Schedule Chart (PDF,MPP) (To Be Updated)

Type-A (Takahashi)

  • Minutes of Type-A Meeting

  • Tansportation: The second transportation for EQ stop parts and tools is scheduled in 10-11th for Kamioka and 12-13th for Y-end in January.
  • EYV chamber: Connection of the top chamber is scheduled in 21st-22nd. TMP, cone bellows, and cross tubes will be assembled.
  • Pre-isolator: The assembly of two pre-isolators for SR is on going in ATC.
  • EQ stop, release sensor, dummy payload: The remain parts were delivered on 12th.
  • BF damper: The production is on going.
  • Maraging wire: The production is on going.
  • Tooling for installation: The support frame for the PI was delivered and assembled. The fiber scope will be ordered. Fiber scope test will be done by Sato-san.

Type B (Mark)

  • Activity report for week of 12/12
    • Mark, Fabian and Enzo continued BS Test Hang work:
      • We shipped BS mirror box parts to Shoda-san and components for a new LVDT cable to Hirata-san.
      • We posed for pictures of the BS by a team from National Geographic.
      • We installed the BF fishing rod stepper motor adaptor cable.
      • We tried to install the BF LVDT cable but first we encountered trouble routing it, and then several wires broke at the D-Sub end.
      • We laid 6 in-air cables from the tank to the PR2 rank for BF and SF picos, steppers and LVDTs.
      • We lifted the BF/IRM/IM/RM/BS section to weigh it and check its balance.
        • It was 195.6 kg, which is 18 kg(!) less than the capacity of the SF.
        • There was a major imbalance in roll: with all four built-in trim masses moved up the +Y end, it still needed 270 g of extra trim mass to be level. This can probably be made up easily by designing the 18 kg of extra mass appropriately.
      • Unfortunately when we put the payload, the IM was slightly yawed and ended up on the horizontal EQ stop screws. This let the IM-BF maraging rod go slack, which disturbed the leveling of the IM (because every time it is picked up the maraging rod settles in a different place, giving a different suspension point).
      • We removed the end panels of the IRM to get access to the IM and rearranged the trim mass on the the IM to get it balance to bubble-level precision. (We still need to do fine pitch adjustment with the OL so that the BS is at the right angle, secure the trim mass properly and replace the IRM panels and OSEMs.)
    • Miyakawa-san and Yamamoto-san redid the cabling from the computer room to the PR2 rack and expected to finish by lunchtime on Friday.
    • Hirata-san
      • Did parts and fastener lists for the SR payload.
      • Did a 3D model with the SR suspension on the BS assembly frame (to help Mark make adjustments to the frame design).
      • Did 2D drawings of Fabian's concept for BS EQ stop parts.
      • Did a 3D model of a wire clamp with replaceable jaw parts (to avoid having to reuse parts with scars from pressure).
      • Did 2D drawings of a new wire clamps for on top of the BS and SR RMs.
  • BF issue
    • The BF has four issues that may or may not be related:
      • The keystone is sitting at an angle, so the bottom of the keystone just barely clears the magnet yoke without rubbing.
      • The suspension point for the IM rod is offset. Thus:
        • The BF does not hang level when the IM is suspended from it, even with all built-in trim masses moved to their limits (an additional 270 g stacked on the +Y side of the cap is required).
        • The offset of the rod also causes an offset of the IRM and IM, which uses up all the adjustment range of the IRM OSEMs and means the EQ stops screws between the IRM and IM cannot be inserted without rubbing.
      • The load capacity is slightly less than measured by Hirata-san during tuning at the ATC.
      • The frequency is rather higher than measured by Hirata-san.
    • Also, the BF/IRM/IM/RM/BS system is 18.1 kg light (195.6 kg) compared to the load capacity of the SF (213.7 kg).
    • Diagnosis:
      • The direction of the tilt lines up exactly with one of the blades (the one in the +X,+Y direction on the assembly frame).
      • The blade bases are adjusted symmetrically relative to the outer edge of the BF.
      • Therefore the +X,+Y blade is probably either stronger or weaker than the other two.
      • However even if this was true at the ATC, something has changed during transit.
      • Designing asymmetric trim mass would fix the imbalance problem but not the offset problem (IRM and IM would still be displaced; EQ stop screws could still not be used).
    • Quick summary: this is a major nuisance and is repeatedly costing us time, but we could probably make it work if we absolutely had to.
    • Options:
      • Muddle through.
        • Slow, risky.
      • Bring the BF back to ATC for a tuneup before proceeding with the test hang.
        • Could almost certainly fix the frequency problem.
        • Might be able to fix the offset and/or tilt problems by swapping in the spare blade.

        • Might be able to fix the offset problem by adjusting the blade bases to different distances from the edge.

        • If successful, makes some subsequent steps simpler and/or safer (less asymmetrical trim mass; IRM/IM stops can be used).
        • Reduces the chance of discovering a show-stopping problem with the BF later.
        • Might delay design of 18 kg of trim mass (unless it's very adjustable).
        • Delays finding any problems in other areas (SF, PI etc).
        • Would distract Hirata-san from SRx procurement at a crucial time.
      • Allot time for a tuneup between the test hang and the real hang.
        • Same chance of success at fixing the immediate problem as above.
        • Possible worse delay design of 18 kg of trim mass (unless it's very adjustable).
        • Test hang work is harder and slower.
        • Greater chance of running into a show-stopping problem related to the BF and having to back up in the test hang.
        • Advances finding any problems in other areas (SF, PI etc).
        • Could allow more spare blades to be ordered - better chance of getting a well-matched set.
        • Probably better for Hirata-san.
      • ???

Type-Bp (Shoda)

  • Test hanging Preparation
    • PR2/3 Assembly frames are constructed.
    • Stab flags, Stab flag gluing jigs, New IM flags, and PR wire breakers are delivered.
      • Hirata-san and I tested the assembly for the stab flags and stab flag gluing jigs at Mitaka.
    • Now gluing is under preparation. (I found two of the wire breaker holders. The stages and the other two are missing.)
    • Additional parts for payload (ballast masses for IM) are delivered.
    • RM base modification is almost done. The new parts are still under machining and they will be delivered next week.
    • Wires, mirror box related parts, all the new parts delivered at Mitaka will be sent to Kamioka.
  • To do
    • LVDT combiner final check for new LVDTs (some of the electronic parts are still missing)
    • establish mirror disassembly procedure
    • Buy gluing tools for KAGRA use.

IMMT (Ohishi)

  • Put a report here

Watchdog system (Tanaka)

  • I'm working on designs(design of PCB and chassis design).
    • Main board for WDS(To reduce the size.) 100mm-150mm --> 75mm-150mm.

    • 19-inch rack 1U(height)(design of Placement in the case).


  • Incidents:
  • Foreseen risks
    • PI installation into the vacuum chamber: confirmed the procedure.
    • PR3 assembly: will proceed to the alignment of the mirror within the mirror box in the next week. Jigs are modified to make this process safer.


  • Bottom of the magnet bases (Aso)
    • Technically, it is better to make the magnet stand smaller (for thermal noise, mechanical resonance etc).
    • For PR, the thermal noise is not an issue. Since the PR3 installation is planned very soon, we will not make the change to the PR suspensions.
    • For BS and SR, we want to do this modification, which requires new coil bobbin design and a (much) smaller magnet stand.
    • Production of coils including the winding will take at least two months. The real BS installation will start from mid-April. So, we need to finish the design by the end of Jan.
    • Question is whether we can get support from ATC or not. Aso will consult with Akutsu on Monday.

  • Wires for RM. 0.65 (seems to be too thick), 0.6, or more thinner?? (Shoda)
    • PR3 test hanging will use 0.6mm.
    • Need to finish the simulation before the real optics is suspended in Feb.
  • Design change procedure.
    • If we make changes to the design of the suspension, the information should be sent to the VIS ML.
    • For small trivial changes, each team leader can make a decision. Otherwise, any change to the suspensions should be discussed in the VIS subsystem.

Site work plan for the next week

  • Mon: extended chief meeting
  • Tue: PI installation/PR3 test hang
  • Wed: PI installation/PR3 test hang
  • Thu: PI installation/PR3 test hang
  • Fri: Holiday

Travel Plans

  • Travel (Week of 12/19):
    • Takahashi: 19-22 (Ext. Cheif Meeting/PI install)
    • Shoda: 19-22 (Ext. Cheif Meeting/PR3 test hanging)
    • Mark:
    • Fabian:
    • Okutomi: 19-22 (Ext. Cheif Meeting/PR3 test hanging)
    • Fujii:
    • Ishizaki: 20-22 (PI install)
    • Hirata:
    • Sato:
    • Enzo: 20-22 (PR3 test hanging)
    • Ohishi: 19 (Kashiwa)
  • Travel (Week of 12/26):
    • Takahashi:
    • Shoda: 26-28
    • Mark:
    • Fabian:
    • Okutomi: 26-28
    • Fujii:
    • Ishizaki:
    • Hirata:
    • Sato:
    • Enzo: 26-28
    • Ohishi:

Next meeting

On 2017/1/6(Fri)

KAGRA/Subgroups/VIS/VISMinutes20161216 (last edited 2016-12-21 10:07:39 by MarkBarton)