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==== Report for week of 4/23 ====
 * We hung the optic and set its pitch. The winch system had a lot of slop in it but the technique of relaxing the wires by lifting the optic on the EQ stops was effective in getting consistent results.
 * We tightened the clamps using a torque wrench, using settings of 5 N.m for the primary clamps and 20 N.m for the secondary.
 * We hung the RM and set its pitch. The RM winches were a lot more consistent.
 * However when tightening the clamps, the wire on the +Y side broke at the bottom edge of primary clamp. The wire on the -Y held, so the RM dropped a few mm onto the trolley on the +Y side.
 * We raised the RM trolley to support the RM and left the optic hanging inside it overnight as a safety test.
 * We then reversed the usual installation procedure to remove the RM and get the mirror box around the optic. We used clamp pieces as spacers to bridge the gaps created by the fact that the optic had been raised 3 mm during hanging and could not safely be lowered. We then cut the wires, leaving the op
 * Shoda-san made SRM model (Dropbox/Largefiles/Subsystems/VIS/Design/SR/Model/SRM-MetalMass_180426)
 * Shoda-san made 2D drawings of LBB ballast masses
 * Hirata-san washed parts.
==== Control Issues ====
 * Resonant frequency table is ready for BS ([[http://gwwiki.icrr.u-tokyo.ac.jp/JGWwiki/KAGRA/Subgroups/VIS/TypeB/BSdetail|BS suspension details]])
 * We found the inconsistency between local damping measurement and interferometer measurement. ([[http://klog.icrr.u-tokyo.ac.jp/osl/?r=4811|klog4811]])
  The TF gains from IML to TML, and from TML to TML are different from the interferometer measurement.
==== Report for week of 5/7 ====
 * We inspected the wires and clamps involved in the wire break.
  * The scars on the clamp on the tungsten wire that failed had very different depths, with the one that failed being much deeper, so probably the clamp piece was not completely straight before tensioning. However one wire on the other side was also badly crushed and on the point of failing, so the tension was clearly too much.
  * We decided on new torque specs of 2 N.m for the primary clamps (down from 5 N.m) and 10 N.m (down from 20 N.m) for the secondary. The secondary clamp spec, for M6 screws, is now based on the LIGO policy of using the maximum suggested for the screw and the LIGO value for a coated 1/4-20 screw (100 in-lb = 11.3 N.m), and the primary clamp spec is derated by 2/3 from the spec for an M5 screw because the clamp pieces are recessed and only grip the wire at narrow sections along the edges, concentrating the force.
  * None of the screws showed any signs of damage.
  * All of the scars on the primary clamps were shallow enough that could reuse the clamp pieces. The tungsten secondary clamps were never tightened, and the outer pieces of piano wire secondary clamps were badly scarred but could be reused upside down.
 * We successfully rehung the SR3 and RM. In the process we noticed and fixed an issue with the assembly frame (due to an out-of-date number in the Mirapro diagram, the IM crossbars were set 3 mm too high, which would have affected the wire length).
 * We added the sections of the security structure below the RM and up to the BF.
 * We installed the TM OSEM cables and routed them up to the IM.
 * We installed the load gauge adapter and load gauge and prepared the IM/... section for weighing.
 * We removed the three cracked F0 blades from the PI #3 in the SRM, and prepared for testing prototype new blades in that PI. We removed a floor panel under the PI and set up the filter service trolley underneath it with a stack of masses for a dummy load.
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  * I checked the TML gain, which are calculated from TMP and TMY measurements, and found EUL2COIL matrix was different from what I supposed.
   --> Fixed it and updated the state space model. Might be OK now for TF from TML to TML. (Komori-kun will check it.)
  * I checked the calibration gain of OSEMs and found that the measured values are not used. But it makes only small difference.
  * Compare the TFs from BFGAS to BFGAS and BFGAS to IMV, and they are inconsistent for BS and PR2. (No data found for PR3)([[http://klog.icrr.u-tokyo.ac.jp/osl/?r=4807|klog4807]])
  * Comparing TFs from IMP to TMP and from IMY to TMY also helps to check the OSEM calibration by comparing OSEM signals and Oplev signals.
   Found the matrix to convert OSEM signals (um) to pitch (urad) is different from what I calculated. To be checked.
   The measurement will be done after phase-I.
==== Plan for week of 5/14 ====
 * Mark, Enzo, Hirata-san, Kozu-kun at Kamioka Mon-Thu, then Osaka.
 *
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 * Constructing the tool to implement the current filterbank information to state space model. ==== Plan for week of 5/21 ====
 * Mark, Enzo, Hirata-san, Kamioka Mon-Fri.
 * Kozu-kun at Kamioka Wed-Fri.
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==== Plan for week of 4/30 ====
 * Shoda-san at Mitaka.
 * Mark, Enzo at Kamioka Mon-Wed or TBD.
 * Others having fun doing Golden Week stuff.
 * --
 * Observe KAGRA Phase 1 operations, assist if problems arise.
 * Do BF TFs.

==== Plan for week of 5/7 ====
 * Shoda-san at Mitaka.
 * Enzo at Kamioka from Tue.
 * Mark, Hirata-san at Kamioka full week.
 * Kozu-kun at Kamioka??
 * Tanioka-kun at Kamioka Mon, Tue.
 * --
 * Continue SR3 Hang
  * Inspect clamps and decide whether to reuse or swap in clamps from SRM IM.
  * Rehang optic.
  * Rehang RM.
  * Cable RM OSEMs.
 * Prepare for filter testing
  * Remove cracked blades from F0 #1 and #3.
  * Remove floor panel in SR3 area.
  * Set up filter building trolley with crossbars, jacks and F0 test masses.
==== Plan for week of 5/28 ====
 * Mark, Enzo, Hirata-san, Kamioka Mon-Fri.
 * Kozu-kun at Kamioka Mon only.
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 * Etc
  * Test prototype SR3 safety bar, and set up second safety bar.
  * Negotiate with Mirapro to get SRM mushroom installed, avoiding 5/15.

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 * Fabian vacation, 3/26-4/27 (then gone).

Scraps of text for incorporation in the VIS Meeting Minutes

KAGRA/Subgroups/VIS/MeetingNAOJ

Type B (Mark)

Report for week of 5/7

  • We inspected the wires and clamps involved in the wire break.
    • The scars on the clamp on the tungsten wire that failed had very different depths, with the one that failed being much deeper, so probably the clamp piece was not completely straight before tensioning. However one wire on the other side was also badly crushed and on the point of failing, so the tension was clearly too much.
    • We decided on new torque specs of 2 N.m for the primary clamps (down from 5 N.m) and 10 N.m (down from 20 N.m) for the secondary. The secondary clamp spec, for M6 screws, is now based on the LIGO policy of using the maximum suggested for the screw and the LIGO value for a coated 1/4-20 screw (100 in-lb = 11.3 N.m), and the primary clamp spec is derated by 2/3 from the spec for an M5 screw because the clamp pieces are recessed and only grip the wire at narrow sections along the edges, concentrating the force.
    • None of the screws showed any signs of damage.
    • All of the scars on the primary clamps were shallow enough that could reuse the clamp pieces. The tungsten secondary clamps were never tightened, and the outer pieces of piano wire secondary clamps were badly scarred but could be reused upside down.
  • We successfully rehung the SR3 and RM. In the process we noticed and fixed an issue with the assembly frame (due to an out-of-date number in the Mirapro diagram, the IM crossbars were set 3 mm too high, which would have affected the wire length).
  • We added the sections of the security structure below the RM and up to the BF.
  • We installed the TM OSEM cables and routed them up to the IM.
  • We installed the load gauge adapter and load gauge and prepared the IM/... section for weighing.
  • We removed the three cracked F0 blades from the PI #3 in the SRM, and prepared for testing prototype new blades in that PI. We removed a floor panel under the PI and set up the filter service trolley underneath it with a stack of masses for a dummy load.

Plan for week of 5/14

  • Mark, Enzo, Hirata-san, Kozu-kun at Kamioka Mon-Thu, then Osaka.

Plan for week of 5/21

  • Mark, Enzo, Hirata-san, Kamioka Mon-Fri.
  • Kozu-kun at Kamioka Wed-Fri.

Plan for week of 5/28

  • Mark, Enzo, Hirata-san, Kamioka Mon-Fri.
  • Kozu-kun at Kamioka Mon only.

To-Do Lists, Schedule

Vacation Info

KAGRA/Subgroups/VIS/TypeB/Minutes (last edited 2022-07-01 13:49:37 by fabian.arellano)