The OPAL Discussion Forum

[Steve Russell <srussell AT lanl.gov>]

Norman,

I've run your problem and am puzzling through things. There does seem to be something amiss in the bend element which I'm tracking down. Basically, OPAL seems to calculating the wrong bend length, which translates to the wrong bend angle, and I'm not sure why. Part of the problem is that you specify a design energy of 500 MeV, but your beam is actually 1090.08 MeV, but that is not the whole problem.

As for the change in the px-x phase space I would argue that it is physical. When you include fringe fields, the y field component peaks on the midplane and falls off for particles with nonzero y. This translates into a change in px like you see via the vz * By term. Try plotting px vs y after the magnet entrance and you can see a more rational looking plot.

I'll let you know when I understand what else is going on.

Steve


On 11/17/2011 04:29 PM, Norman Huang wrote:

Yi-Nong and I do not know how to interpret these SBEND results. Please take a look at my test cases summary. Attached are the OPAL input file (qf.in), Enge coefficient file (FAND1.T7), single particle tracking data (particleInfo_Fringe.txt, particleInfo_NoFringe.txt)

The 12 columns for the particleInfo files are:
Bx     By     Bz     X_ref     Y_ref     Z_ref     Px     Py     Pz     X_local     Y_local     Z_local

Regards
Norman

-- 
Steve Russell
Scientist
MS H851
P.O. Box 1663
Los Alamos National Laboratory
Los Alamos, NM 87545
USA
Phone: (505) 665-3712
Fax: (505) 667-8207

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