I'm wondering about the best way to implement an energy mismatch in Elegant. For example, I have an energy that the transport line is designed for, but I want to put a different energy beam through it. I thought MALIGN or ENERGY would do it, but am not sure how to best implement it.
Thanks.
Energy Mismatch
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michael_borland
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Re: Energy Mismatch
Chris,
This can be done with either an ENERGY or a MALIGN element. Which you use is just a matter of convenience.
Using the MALIGN element, you'd set DP equal to the fractional momentum offset of the beam relative to the design momentum. Using the ENERGY element, you can redefine the reference momentum at any point in the beamline. If the beam's average momentum differs from the defined reference momentum, then you'll have any energy offset. In either case, you can use vary_element to vary the momentum error if that's interesting.
Another option is to use the Po parameter in bunched_beam to give the beam an initial average momentum that differs from p_central defined in run_setup. If you are using sdds_beam, you can simply define the beam to have an average momentum different from run_setup/p_central.
If the system has rf cavities, then you need to exercise care that the rf cavity phasing is what you expect. By default, elegant phases the cavities to the beam. Check the manual
http://www.aps.anl.gov/Accelerator_Syst ... ode13.html for more information on this.
--Michael
This can be done with either an ENERGY or a MALIGN element. Which you use is just a matter of convenience.
Using the MALIGN element, you'd set DP equal to the fractional momentum offset of the beam relative to the design momentum. Using the ENERGY element, you can redefine the reference momentum at any point in the beamline. If the beam's average momentum differs from the defined reference momentum, then you'll have any energy offset. In either case, you can use vary_element to vary the momentum error if that's interesting.
Another option is to use the Po parameter in bunched_beam to give the beam an initial average momentum that differs from p_central defined in run_setup. If you are using sdds_beam, you can simply define the beam to have an average momentum different from run_setup/p_central.
If the system has rf cavities, then you need to exercise care that the rf cavity phasing is what you expect. By default, elegant phases the cavities to the beam. Check the manual
http://www.aps.anl.gov/Accelerator_Syst ... ode13.html for more information on this.
--Michael