Log entry time 20:13:09 on September 6,2009

Entry number 288323

Ran dithering again tonight, and the response looks significantly better.  This 
is both because of some unexplained drift that may have improved the response 
of the coils I tested yesterday, and because I ran additional coils that I 
didn't test yesterday (I wasn't sure they were still enabled).  

Results are below, from run #12055.  Everything was run with an amplitude of 
100, except for coils 4 and 5 (amplitude = 250) and energy (amplitude = 50). 

The absolute calibration of the energy change is in question.  According to 
accelerators "FOPT" diagnostic, the dispersion at 1C12 is the same as it is in 
the arc, but the arc should be ~2m and the 1C12 should be about 4 meters.  I 
think we will need to get this settled eventually, since it does bear on our 
ability to measure energy slopes. 

I will implement this for regular running now.  Alexandre will be a little 
cautious with the Compton electron detector to make sure there is nothing 
dangerous there.

Figure 1 is the dithering reaction in each bpm (there is a significant slow 
drift over the measurement period).  Figure 2 is the same thing, but with both 
dimensions read out for bpm12 and with 4a/4b decomposed into angle and position 
on target.