Pengbo, Simon

after the successful polarization test, we started to do also the absorption tests in order to see whether we can reproduce our results from before the upgrade.

Actually, the first test was performed with the TAMA#1 sample but we repeated the test with Shinkosha#7 since we don't have any direct reference for TAMA#1.
We can say that the actual results in terms of the absorption coefficient are well reproducible (see attached figures from before [Z = 74.1] and after [Z = 80] the upgrade).
However, there is an issue with the "effectivity of absorption", meaning that we get a factor of 2-3 smaller AC-values than before. The reason is still not quite clear to us. It may be that the size of the beam-waist, which is 10% larger than before, has a bigger influence on the AC-value than anticipated. We will try to further reduce the waist and see what may happen.

At least we can exclude that the polarization of the beam has any significant influence on the absorption. We have tested this yesterday as well.