J. Kissel, T. Sadecki

While I'm not incredibly confident in the results, I wanted to post them such that the SUS group at large can ponder overnight and give us advice or direction if need be for tomorrow.

Attached are spectra of the QPD from the temporary shadow-sensor setup surrounding H1 SUS ITMX at the moment (for set-up pictures, check out LHO aLOG 38742). The sensor is aligned to the +X / +Y fiber, or closest to the HR surface, on the left looking at the HR surface. 

Given the potential danger to the fibers and lack of cleanliness of the speakers, we elected to go with what ambient noise excitation the purge air and clean rooms were providing. Seems to be enough...

Evidence that these are indeed violin modes I'm measuring:
- Features at roughly the right expected frequency (including inharmonicity)
- No other features besides 60 Hz harmonics
- Some evidence of mode-splitting in the higher harmonics

Open Questions:
- Is this enough harmonics, or would you like us to go higher?
- Is this a high enough frequency resolution / BW?
- Do you expect to see mode splitting?
- Is this consistent with what data we have for previous in-air measurements of this fiber?
- Why so low in Q? Yes, Qs decrease in air, but I wouldn't think *that* much...

We closed the day by aligning to a new fiber, which, upon first glance also shows a feature at ~500 Hz...