How to include tune response into orbit response fitting
Posted: 07 Jul 2008, 11:21
Here is the trick that allows one to include tune response (e. g. dQx/dK1 for some quadrupole) into orbit response fitting with Elegant.
It's possible to find the exact solution for dQ/dK1 as a function of Twiss parameters at the beginning of the quadrupole (see the attached pdf for details).
Using this formula in the form of rpn-expression you can include dQ/dK1 into orbit response fitting with Elegant as an additional optimization term (see TuneResponseFit.tar.gz).
Note, that coupling is not taken into account in this formula and close to coupling resonance it is not valid.
It also would be very nice for Elegant to have this tune response fitting as a built-in option.
It's possible to find the exact solution for dQ/dK1 as a function of Twiss parameters at the beginning of the quadrupole (see the attached pdf for details).
Using this formula in the form of rpn-expression you can include dQ/dK1 into orbit response fitting with Elegant as an additional optimization term (see TuneResponseFit.tar.gz).
Note, that coupling is not taken into account in this formula and close to coupling resonance it is not valid.
It also would be very nice for Elegant to have this tune response fitting as a built-in option.