I looked at the ITMY HWS spherical power after our last high power lockloss on Friday (right now there is no green filter in front of the camera so I needed a lockloss where ALS remained unshuttered). The data looks interesting - it takes a few hours for the spherical power to settle. I plotted it against the data from April 2021 and Aidan's comsol model of ITM self heating. The absorption looks the same as last year. This indicates that there are no new point absorbers on ITMY.

The absorption in ppb quoted in the April alog is wrong because we were overestimating our circulating arm power. Using the updated April 2021 arm power (260kW) we have 369ppb absorption in ITMY.

The script to generate this plot lives in

/ligo/gitcommon/labutils/hws_absorption_fit

and is commited and pushed to the git repo.