With Fabian and Hirata-san.
- We inspected the blades more carefully. Two look OK, but unfortunately the third (the one immediately anticlockwise from the magic wand) has a large number (≈15) of suspicious cracks, mostly along one edge. There is also some brownish discoloration in that general area. See attached diagram.
- Many of the cracks are in the shape of a very flat X. The largest ones are about 8 mm long and about 1-2 mm tall. See attached photo.
- We will not work further with this filter until we get an expert opinion.
- This afternoon we will bring the third SR top filter into the SRM section of the cleanbooth and inspect it in case it also has problems.