[Bteam] H vs C arc dipole multipoles

[Jay Benesch]

I have modeled the BE magnet with and without H steel with the "same" 
mesh, turning iron to air to get the C.  I am modeling the BA the same 
way now.  For the latter I have models at J=50, 100, 150, 200 and 225 
A/cm^2; I=1.265*J.  Even at low B the H magnets have higer BdL at the 
same J.  BB next.  Actually I have models to J=450 but they're not 
relevant to the final 5.6 GeV run.

For multipoles I scale the beam energy to the BdL of the model, inject 
the beam at the right angle and offset to get the proper sagitta, and 
let it propagate in 2.5mm steps.  The post-processor gives me an orbit 
and velocity file which I translate into position and Euler angles.  I 
run the post-processor again to get the field at 24 points on 1cm radius 
circles with centers and angles taken from the orbit file.   I then have 
the post-processor give me mulitpoles to n=5 (12 pole).  This gets the 
quadrupole term wrong, as Mike Teifenback taught me.

I plan to run the beam through the C magnet to get an orbit and then use 
this orbit for both C and H magnets.

Comments?

Jay