KAGRA Logbook

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VIS (SR2)

mark.barton - 20:10 Monday 09 July 2018 (5485)

SR2 Installation

For Hirata-san and Terrence.

Today:

Because 32 mm of compression gave frequencies that were more than low enough, they decided to try backing off to 31 mm (as for SR3) to try to claw back a bit of load capacity, which is likely to be more important.
They did the blade adjustment and measured the frequency and load capacity. Hirata-san will post a graph as a comment to this post.

Comments to this report:

naoatsu.hirata - 11:05 Tuesday 10 July 2018 (5487)

We measured the SR2 top filter optimal load and frequency with the CuBe blade.

We expected 31mm compression would have a wider load range butthe difference was not so big. And there is crossover point around a load of 20mm or 248.5kg.

From the viewpoint of load capacity, 32mm compression is better below this crossover point (keystone higher). CAD nominal was 16.5 mm and the SR3 needed 11 mm, so 32 mm compression will almost certainly be better.

And from the viewpoint of frequency, 32mm is also better than 31mm.

So we will set 32mm compression.

Non-image files attached to this comment

sr2topfilteradjustment180709.pdf