R. Kumar, S. Dwyer, C. Compton, R. Short

Following the work done yesterday adjusting the preload on the ZM4 PSAMs (alog91471), Rahul and I set about adjusting it further today to get our calculated projected beam size on SRM close to where we want it. Using the same procedure as yesterday, I turned off the ZM4/5 PSAM drive chassis, Rahul went into HAM7, locked down ZM4, torqued the preload about 1/8" of a turn (it's hard to quantify a torque spec in this manner), then finally unlocked the suspension. I moved the ZM4 pitch alignment slider about -1400 counts to realign the beam on SQZT7 to our alignment irises as a result of this torque adjustment. I then proceeded to take a couple of beam profiles on the table with the M^2 device to see where we landed. This plot [initial] shows the difference between before and after this adjustment in terms of the projected beam at SRM with a few different PSAM settings on ZM4 and ZM5. The four points I took here informed us that we could stand to torque ZM4 a bit further to hopefully line up with the center of the plot.

Rahul went back into HAM7 and torqued another 1/8" and I took another couple of profiles after (I did not need to move ZM4's alignment sliders after this adjustment). I took a total of nine profile points here, all of which can be seen compared to other measurements today on this plot [full]. Since there are points in the bullseye, we decided to stop here and that this is where the ZM4 preloading will stay. This plot [final] shows just the beam profiles taken at our final preloading position.

Tomorrow we will move on to final closeout checks in HAM7.