Per ECR E1900176, FRS 13051, WP 8364,  measured the effect of moving the IO high power beam dump hoses.  The largest changes were seen at 420Hz, 480Hz, and 550Hz, where the coherance peaks at those frequencies, between the PSL periscope Y accelerometor and the IMC WFS signal WFS A Yaw measured anywhere between 0 and 0.6.  Of course there was no one hose position that minimized alll of the peaks, but the changes, with changing the hose locations, were easily identified.

Hose positions tried:

1. original mount/position
2. original mount, dteached from the table, hoses suspended from the high power beam dump
3. additional damping material/mount, hoses suspended from the high power beam dump
4. additional damping material/mount attached to the table, in 3 locations
   1. closer to the beam dump,
   2. at the position of the original  mount
   3. farther away from the beam dump
5. additional damping material/mount, farther away from the beam dump, human intervention to hold the hoses coming out of the beam dump as straight as possible
6. original mount/position, upgraded damping for each individual hose, each hose now has individual damping foam, and where there was one layer of foam before, there are now two layers of damping foam around each hose, where it attaches to the mount, the damping for the mount is unchanged

It was clear that there were outside influences to the measurements, and I suspect first and foremost the temperature of the PSL, so the coherance at 550Hz was low when we started, and high when we left, and I believe the coherance will decrease as the PSL temperature returns to steady-state Scinence Mode.

Plots will be added later.

- Jason, Cheryl