• KAGRA
• Subgroups
• VIS
• TypeB
• Minutes

Scraps of text for incorporation in the VIS Meeting Minutes

KAGRA/Subgroups/VIS/MeetingNAOJ

Type B (Mark)

Report for week of 3/13

At Kamioka (Mark, Fabian, Enzo, Perry, Hirata-san):

• We took a full set of TFs with the BF stationary but the IRM, IM, RM and TM all hanging.
• We marked peeling or damaged areas on the clean booth floor for Furuta-san.
• We installed the SF, measuring its weight in the process.
• We found the crossbars supporting the SF jacks were too high to allow the SF ring to sit on the pillars while also being partially supported by the jacks. (This was an issue with the 3D CAD - the model of the NB-01 jack had a lower minimum height than reality.) We lowered the crossbars by 5 mm and put thicker spacers (12 mm instead of 3 mm) on top of the jacks supporting the SF and everything worked well.
• We installed newly cleaned L-brackets under the BF and SF.
• We installed a new-style cable clamp under the SF. (This was easier with the SF on the security structure, so we had not done it earlier.)
• We installed the SF-BF rod and hex cable clamp.
• We suspended the BF/IRM/IM/RM/BS section and found it was light, presumably because it had been trimmed according to the Promec measurement of the SF, not Hirata-san's later value.
• We added extra ballast mass corresponding to the difference and found the BF section floated at a good height.
• We moved trim mass around on the BF until it hung level, and adjusted the IRM and OSEMs until the IRM-IM EQ stops were well-centered and all the OSEMs were centered laterally and mid-range.
• We ran 11 extra 20-m in-air cables from the tank towards the rack. (We will need to add 10-m extensions.)
• We connected most of the cables to the vacuum flanges with screws and anti-feedthrough adapters. (Some remain to be done.)
• We debugged a 900 Hz ringing in the BF LVDT, which turned out to be because the damping was enabled without appropriate filters or gains.
• We debugged excess noise in the TM-H3 OSEM, which turned out to be mostly due to a faulty cable. However we worry that some of it may be due to some extensions made of non-vacuum-compatible ribbon cable which we added because the TM-H2 and -H3 OSEM cables are too short.
• We installed new security structure parts at the RM level.
• We found all the parts for the lower breadboard suspension, including the blades, blade bases, associated cable clamps etc. We also found the jigs for installing the blades.
• Fabian finalized the BF ballast mass design and started on the SF.

Report for week of 3/21

At Kamioka (Mark, Fabian, Enzo, Perry, Hirata-san):

• We took a full set of TFs with the SF stationary but the BF, IRM, IM, RM and TM all hanging.
• We also did a TF from BF LVDT actuation and confirmed that it was working.
• We got SUMCON running on Perry's computer and worked out how to do cut-down versions of Fabian's full Type-B model corresponding to the various partial configurations we have data for.

Plan for coming weeks

For more detail, see KAGRA/Subgroups/VIS/TypeB/ToDo.

Week of 3/21:

• Lots of electronics: BF picos, SF LVDT and stepper, routing of in-vac cabling past SF, in-air cabling for PI.
• Pick up and weigh entire system from SF down.
• Prepare PI: reattach LVDT double coils, install FR and magic wand.
• Prepare LBB blade units.
• Clear floor for re-coating.

Week of 3/27:

• f2f Meeting