The first figure shows the jitter peaks in DARM from last night and their coherence with PSL table accelerometers, along with the same plot from May 1. Little has changed.

The second figure is a reminder that the jitter is mainly driven by the chilled water flow to the HPO. The vibration from this flow didn’t change much between May 1 and June 8. However, it is greater than it was during O1. We might get significant improvement in DARM by turning down the flow to the specified minimum flow.

Because of the similarity in the jitter noise, Im guessing that only minimal PEM injections will be needed to characterize coupling in last night’s state before we continue commissioning and try to reduce jitter coupling.