betsy.weaver@LIGO.ORG - posted 13:33, Thursday 13 August 2015 - last comment - 14:20, Thursday 13 August 2015(20513)
Optic Modes - FEA table summary of Butterfly and Drumheads
The Butterfly and Drumhead modes of various optics are summarized below. This is taken from work performed by Calum, etal (CIT) in T1500376 on most optic types, and Slawek (MIT) in T1400738 on the test masses.
| OPTIC | MODE SHAPE |
FREQ Hz model T1500376 |
MEASURED / ALOG |
FREQ Hz model T1400738 |
| BS |
BUTTERFLY x-pol |
2449.7 | 2449 / 19440 | |
|
DRUMHEAD |
3623 | |||
| ITM/ETM |
BUTTERFLY x-pol |
6061.7 | 6053.81 / 19968 | 5934.6 |
|
DRUMHEAD |
8198.8 | 8029.1 | ||
| HLTS (PR3, SR3) |
BUTTERFLY x-pol |
6239.5 | ||
|
DRUMHEAD |
8753.5 | |||
| Surrogate SRM |
BUTTERFLY x-pol |
8616 | ||
|
DRUMHEAD |
13080 | |||
| HSTS (MCs, PRM, PR2, SR2) |
BUTTERFLY x-pol |
12637 | ||
|
DRUMHEAD |
17416 |
Note, I have only summarized the x-polarized butterfly mode because all of our drives to optics are along that axis, not the +-polarized direction. It would be hard to drive the +-pol mode so we don't think we'll see them anyways. As well, the modeled x-pol is the same freq
Recall, the RESONANCE WIKI is here.