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 In the process we noticed and fixed an issue with the assembly frame (due to an out-of-date number in the Mirapro diagram, the IM crossbars were set 3 mm too high, which would have affected the wire length).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.
• Mirapro installed the SRM mushroom.

Plan for week of 5/14

• Mark, Enzo, Hirata-san, Kozu-kun at Kamioka Mon-Thu, then Osaka.
• Weigh IM/... section.
• Characterize F0 blade prototypes.
• Remove F0 blade prototypes (and send for rework if necessary).
• Start characterizing LBB blades.
• Crane in BF.
• Add IRM top plate, maraging rod, flying saucer.
• Suspend IM, check pitch, roll and vertical, adjust trim mass.
• Cable and (re-)test TM OSEMs, IM picos, BF yaw pico, BF LVDT and FR.

Plan for week of 5/21

• Mark, Enzo, Hirata-san, Kamioka Mon-Fri.
• Kozu-kun at Kamioka Wed-Fri.
• Install IRM sides, and IM OSEMs.
• Center IM OSEMs (in/out and laterally)
• Route all cables to underneath BF.
• Add BF internal ballast mass.
• Add BF cap.

Plan for week of 5/28

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

To-Do Lists, Schedule

• KAGRA/Subgroups/VIS/TypeB/March2018

• KAGRA/Subgroups/VIS/TypeB/April2018

• KAGRA/Subgroups/VIS/TypeB/ToDoBS

• KAGRA/Subgroups/VIS/TypeB/ToDoSR

• JGW-L1807779-v1 Type B Schedule (SR)

Vacation Info