User name R. Michaels
Log entry time 09:32:09 on March14,2007
Entry number 195866
This entry is a followup to: 195861
keyword=re: spikes (hitting something)I think the spikes occur because we are hitting a frame edge,
see fig 1 and 2. What's shown is the raster current, and since
this is biased by triggers from the target it is a nice snapshot of
the target density. Note:
1. The data from raster current has essentially no phase advance
relative to the triggers.
2. The data from BPMs have a phase advance because of the active
electronics (few usec = fraction of raster orbit). Result is that
for BPMs the peak may appear in the middle of the orbit, an illusion.
Oh, and there are peaks at min and max because of the frequency
response of BPMs. Meanwhile, raster current is just a dumb pickoff,
hence virtually infinite bandpass.
FIGURE 1
FIGURE 2
