Some of the peaks in Kiwamu’s cross spectrum match PSL jitter peaks (see figure). The figure also shows that estimated ambient levels at some peaks are just factors of 2 or so below DARM. It is not clear how much the periscope work in September improved the peaks between 70-250 Hz, because the post-O1 injection was not loud enough to bring up the peaks in this region, just loud enough to show things were the same or better. I should do louder PSL injections as they may help distinguish between jitter peaks and a broad-band background in this region.