Differences between revisions 3 and 4

Agenda/Minutes of the VIS Meeting on 2019/6/7

2019/6/7 13:30 -

Participants:

Progress report

Site work schedule: [[|XLSX]]

See Klog 9064
SRM IP L and T is blended at ~110 mHz (partially optimized by gradient descent, stopped after 10 iterations, then manually adjusted.) while IP Y is blended at 260 mHz (Lucia's old filter). The stability test was carried over the past weekend with inertial damping and all other stages on. The system seems stable.
To study to performance of the inertial damping, I improvised an OL windshield for SRM.
Another round of diagonalization was carried just because we have better sensitivity.
With IP LVDT damping and other controls on, the residual motion is as follows 9086:

RMS Displacement:

RMS Velocity:

I measured the residual motion with inertial damping, inertial damping without LVDT DC, normal damping without LVDT DC. Results are pretty similar.
I modified the optimization algorithm to allow fine learning. The cost plateaued after ~300 iterations and the blending frequency was at 78.6 mHz. I tried implementing this blending filter but the system went unstable.

The calibration, diagonalization for IP geophones was done.
I measured and fit noise floor for LVDTs and geophones.
I found that the IP geophones have a much higher noise level than those from SRM. (1 order of magnitude higher, see 9088)
This explains why the optimization result of the blending filter converges much quicker than that of SRM, because the geophone noise level limits the blending frequency to be at ~ 130 mHz.
However, when the system went unstable when the blending filter was implemented. I should try a higher blending frequency or manually adjusting the blending filter to have a proper shape.

Help commisioning.
Somehow design better cost functions which could help limiting the blending frequency and changing the shape of the blending filter effectively.
Inertial damping and OL windshield for BS and (SR3, if haven't done already).
Type B Operation Manual.
A more pleasant VIS Status Monitor.

Engineering run on 6/8
Introductory materials (on really really basic stuff that is required for gravitational wave interferometry). Not just for VIS, we should encourage other subgroups to do this as well for narrowing the knowledge gap between subgroups and, more importantly, to help beginners (like Terrence) to get up to speed with the current status of KAGRA.

On 2019/6/14(Fri)

KAGRA/Subgroups/VIS/VISMinutes20190607 (last edited 2019-06-07 14:34:06 by YoichiAso)

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- * Introductory materials (on really really basic stuff that is required for gravitational wave interferometry). Not just for VIS, we should encourage other subgroups to do this as well for narrowing the knowledge gap between subgroups and, more importantly, to help beginners to get up to speed with the current status of KAGRA.
+ * Introductory materials (on really really basic stuff that is required for gravitational wave interferometry). Not just for VIS, we should encourage other subgroups to do this as well for narrowing the knowledge gap between subgroups and, more importantly, to help beginners (like Terrence) to get up to speed with the current status of KAGRA.