Jennie W, Elenna

Today we changed the OFI temperature and monitored the OFI PD A power. At each temperature change, we reran Sheila's OMC fringe wrapping injection to replicate the measurement Sheila and Naoki did in alog 78942.

Results: we did not see a very significant change in the OFI PD A power when we changed the OFI temperature from 37.5 C to 25.5 C. We see a smaller scattering shelf at 25.5 C than we do at 37.5 C.

I saved Sheila's template over into my own directory as /ligo/home/elenna.capote/OFI/OMC_fringe_wrapping.xml

She had old references in that template (different from the alog) that were taken in Sept 2024. Those references indicated that an OFI temperature of 37.5 C had the smallest scattering shelf. Today, Jennie and I saw very little difference between the scattering shelves generated at 37.5 C (nominal temperature), 34.5 C and 30.5 C. Only when we measured at 25.5 C did we see the scatter shelf reduce slightly (plot).

In this plot, I added in Sheila's old references that show the exact opposite result a year ago. Specifically, the 25.5 C measurement from now is very close to the old 37.5 C measurement from a year ago.

At first, I didn't think there was much of a change in the power on OFI PD A. However, looking at the second trend, it looks like maybe the power dropped by a small amount. I might have needed to slow down this test more than I realized (plot). I saved this ndscope template in /ligo/home/elenna.capote/OFI/OFI_TEC.yaml