Need help for providing correct energy

[amal]

Hello,

I am trying to use Elegant for tracking beam from a single magnet (later on to see the effects of CSR). But perhaps, I am not able to provide the correct beam energy in input file. I want to provide the beam (electron) with 300MeV as an input (from other file using SDDS_BEAM command in 6-D). When I provide p_central=587.083 (beta*gama) in RUN_SETUP, output emittance (RMS) mismatches by very large amount with respect to linear case i.e. transfer map by linear matrix of magnet). But when I set p_central_mev=280 in RUN_SETUP (by just hit and trial method), the results are close to linear case. Where I am doing some mistake, I could not understand. Please help me in the matter......For reference, all the three files (.lte, .ele and .sdds for input beam) are attached.
Also do we have some option to change the order of tracking (such as in PTC)in Elegant, if yes what is the synopsis, please?

Regards and thanks,
Amalendu.

[michael_borland]

Amalendu,

There are two problems with your beamline setup. First, you are using INTEGRATION_ORDER=2, which is less accurate than the default INTEGRATION_ORDER=4. There's no reason to do this. Second, you did not set the N_KICKS parameter. The default value of 4 is probably not adequate for a large angle dipole.

The Ruth integrator used by CSBEND is known to have problems with giving the centroid trajectory accurately if the number kicks is too small. The second order version is of course worse than the fourth order version.

If you want to vary the order, you can use the SBEN element. Note that the CSBEND element uses the exact Hamiltonian without expansion, so there's no possibility of changing the order. Perhaps PTC uses an expanded Hamiltonian (I don't know).

--Michael

[amal]

Thanks Michael for reply and clarifying the things......

Regards,
Amalendu.