KAGRA Logbook

VIS (General)

masayuki.nakano - 6:11 Thursday 23 January 2020 (12603)

Suspensions are not really good

The Type-A control is not good. Especially, I could not close the DARM loop with the current ETMX. I tried to fix it, but I don't have enough energy.

I'm sorry to say that, but I feel we should bring everything back. I don't know the reason, but just a copy of the ETMY might not really easy. However, the gentle engagement of the control filters are important, so just concentrate on it.
And then, we should not touch the suspension anymore.

-Note
I doubt the ITMY TM coil does not work. Can someone check it?

Comments to this report:

takafumi.ushiba - 9:43 Thursday 23 January 2020 (12605)

I restored the burt file of k1visetmxp (Jan. 20th, 8:40) at 9:30 today.
I restored the filter bank fille (GPS:1263521806, JST: Jan. 20th, 11:16:28) at 9:50 today.

tomohiro.yamada - 13:35 Thursday 23 January 2020 (12609)

[Yamada, Okutomi]

We found that ITMX TM CD was "LPCD for CRY (s1707384)". So, we replaced it with HPCD (s1604947).

After swapping CDs, we compared acutuator force balance by shaking at 4Hz.

Ratio of "ITMX / ITMY" were following.

H1: 0.966 (using TMP OpLev)
H2: 0.804 (using TMP OpLev)
H3: 0.259 (using TMY OpLev)
H4: 0.810 (using TMY OpLev)

ITMY TM cois are working well.
However, ITMX H3 coil balancing shoud be investigated soon (peak hight of ITMY H3 and H4 are almost same.).

takafumi.ushiba - 15:34 Thursday 23 January 2020 (12610)

[Ushiba]

I finished replacing ETMX filters to previous version.
Attached graph shows comparison between current TM OpLev spectra and that at 20200119 (red is current one and blue is previous one).

Note: somehow previous MN_MNOLDAMP filter doesn't work well.
So, I modified the lead1 filter (currently lead1.3).

Images attached to this comment

masayuki.nakano - 20:23 Thursday 23 January 2020 (12616)

Thanks a lot!!