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| ==== Report for week of 3/12 ==== * We helped Mirapro close up the BS tank, and did last minute checks and adjustments, including using the fishing rods to reset the GAS keystones to mid-range according to the LVDTs. (The F0 had risen so far (≈7 mm) due to temperature changes that it was touching the upper keystone stop screws and defeating the vibration isolation. We operated the F0 FR manually while the tank lid was off.) * We installed electronic boxes in the SR3 and SRM racks. Enzo set the phases and gains on the LVDT drivers for both racks. Rack internal cabling and in-air cabling to SR3 still needs to be done. * Hirata-san disassembled two BFs (one SF BF with a tilted keystone and the BS Test Hang BF) and characterized all 10 available SR BF blades. He found they fell into a group of 6 strong ones and a group of 4 weak ones, so he divided the 6 into two matched sets and rebuilt the two filters. * We noticed that the bottom level of SR2 suspension had developed a significant yaw (enough to foul on the security structure), probably introduced when we picked the chain up to weigh it, so we lifted the suspension again and corrected it. * We aligned the SR2 ready for TFs. We noticed that the IM/... section had a noticeable roll (≈20 mrad) but we were unable to correct it with the IM roll pico (the pico runs but the roll does not change, probably because there is too much friction for the mass return spring). We will see if the TFs look OK and then decide whether to try correcting the roll. * We gathered items for OSEM assembly by Enzo, Shoda-san and others at Mitaka next week, and for geophone assembly by Fujii-kun and Kozu-kun at Kamioka. Hirata-san ordered some M8x35 screws that we didn't have enough of. * We took delivery of the blade bases for the LBB dampers. * Hirata-san packed up two SF caps (the original one from the SR2 SF) and a spare, for remachining by Mirapro. He also packed up the dummy BS and arranged for Ishizaki-san to take it to Mitaka for soaking off of the sapphire prisms. |
==== 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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| ==== Plan for week of 3/19 ==== * Fujii-kun and Tanioka-kun join. * Mark at LVC meeting * Fujii-kun at Kamioka (including Wed 3/21) * Kozu-kun at Kamioka Mon-Tue. * All others at Mitaka * -- * SR2 TFs and control loop development (Shoda-san and Enzo). * Assemble four geophone pods (Fujii-kun and Kozu-kun at Kamioka). * Make two sets of IM OSEMs (Shoda-san and Enzo) * Make last in-air pico adapter cable (Enzo). * Make three in-air stepper splitter cables for SR2, SR3 and SRM (Enzo). * Set up dummy BS prism removal (Hirata-san). |
==== Plan for week of 5/14 ==== * Mark, Enzo, Hirata-san, Kozu-kun at Kamioka Mon-Thu, then Osaka. * |
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| ==== Plan for week of 3/26 ==== * Mark vacation. * Shoda-san at Mitaka * Others at Kamioka * -- * Lay SR3 in-air cabling (Enzo +1). * Finish rebuild of second BF (Hirata-san). * SF Check (Hirata-san). * Check load capacity. * Check fit of caps. * Add cable clamps to bases. * Add cable clamps and Cu segments to caps (only if they fit well). * Cable LVDTs and steppers. |
==== 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 5/28 ==== * Mark, Enzo, Hirata-san, Kamioka Mon-Fri. * Kozu-kun at Kamioka Mon only. |
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| * Mark at LVC, then vacation, 3/18 (Sun) - 4/1 (Sun) * Hirata-san vacation, Mon 3/5. * 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