User name B. Craver
Log entry time 12:26:05 on September30,2006
Entry number 185962
keyword=beam spot plotsThese plots were taken on Run 5379 - the last run before the drop in cryo flow. I added the raster rawcurrent variables to spot++ (and left original copy in the directory.)
The top plot shows vertical beam position vs. event number. I believe it shows that the beam motion in the vertical direction is rapid and consistent.
The second plot shows:
1) Upper left - Beam position vertical vs. Beam position horizontal. The peaks at the right and left edges are the expected false bedposts.
2) Upper right - Raster current vert. vs. Raster current horiz.
It looks to me that the raster currents are as they should be.
3) Lower left - Beam position (as reconstructed by BPM) horiz. vs. raster current horiz.
This phase relation between the detected position (slow BPM) and driving current (fast pickoff) appears normal to me.
4) Lower right - Beam pos. vert. vs. raster current vert.
I believe this shows that the beam position is shifted in the vertical direction.
My interpretation is that the raster is not responsible for the instability of beam position in the vertical direction.
FIGURE 1
FIGURE 2
