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| * 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 three issues that may or may not be related: * The keystone is sitting at an angle, which means: * The bottom of the keystone just barely clears the magnet yoke without rubbing. * The suspension point for the IM rod is offset, so the BF does not hang level, 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 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). |
* Hirata-san: * Received many parts from i-ject for BFRM (took pictures and took them into ATC cleanroom). * got quotes for PRM/SRM payload from i-ject. * Checked quotes and asked for some modifications.) * Washed parts (parts for type-A, small hexagons, screws, etc\) * Wiped 9 piano wires and sent to Kamioka for PR. * pdated Fabian's EQstop parts for BS recoilmass and updated EQstop assy drawings. * Fabian * Worked out geometry for blade adjustment. * Designed additional ballast masses for BS BF (and SR). * Mark and Enzo (at Kamioka) * Did two rounds of adjustment of the blades with help from Takahashi-san (one for position, one for frequency) * Surveyed the position of the rod using the vertical mode of the bubble level. * Got apparent improvement as judged at the IRM-IM EQ stops (but still not perfect). * Did one more round of blade adjustments (without Takahashi-san) * Got good agreement with IRM-IM EQ stops, so put BF cap on and raised the whole system to check for balance. * Found balance still fairly bad: about the same on the -X,+Y diagonal and about half on the +X,+Y diagonal (70 and 30 mm worth of motion of a single trim mass respectively; previous a bit over 70 mm each). * From the imbalance torques, calculated the offset of rod as 2.3 mm in the direction 22 degrees to the +X side of -Y. * Calculated the blade adjustments required: {-0.325194, -1.79175, 2.11695} mm * Prepared to apply adjustments (removed cap etc). |
Scraps of text for incorporation in the VIS Meeting Minutes
KAGRA/Subgroups/VIS/MeetingNAOJ
- Hirata-san:
- Received many parts from i-ject for BFRM (took pictures and took them into ATC cleanroom).
- got quotes for PRM/SRM payload from i-ject.
- Checked quotes and asked for some modifications.)
- Washed parts (parts for type-A, small hexagons, screws, etc\)
- Wiped 9 piano wires and sent to Kamioka for PR.
- pdated Fabian's EQstop parts for BS recoilmass and updated EQstop assy drawings.
- Fabian
- Worked out geometry for blade adjustment.
- Designed additional ballast masses for BS BF (and SR).
- Mark and Enzo (at Kamioka)
- Did two rounds of adjustment of the blades with help from Takahashi-san (one for position, one for frequency)
- Surveyed the position of the rod using the vertical mode of the bubble level.
- Got apparent improvement as judged at the IRM-IM EQ stops (but still not perfect).
- Did one more round of blade adjustments (without Takahashi-san)
- Got good agreement with IRM-IM EQ stops, so put BF cap on and raised the whole system to check for balance.
- Found balance still fairly bad: about the same on the -X,+Y diagonal and about half on the +X,+Y diagonal (70 and 30 mm worth of motion of a single trim mass respectively; previous a bit over 70 mm each).
- From the imbalance torques, calculated the offset of rod as 2.3 mm in the direction 22 degrees to the +X side of -Y.
- Calculated the blade adjustments required: {-0.325194, -1.79175, 2.11695} mm
- Prepared to apply adjustments (removed cap etc).