simultaneous optimisation

[libov]

Hi Michael,

I am trying to do the following. Assume I have some lattice, e.g. a quad triplet. I want to optimise position and strengths of the quads for some beam energy.
Assume I now want this to work for several energies. I can't do optimisation separately for each energy because the quad positions would come out different each time,
so I need kind of simultaneous optimisation for several energies (i.e. the quad strengths can be different for different energies, but the position should be common for all).

I do it in the following way: I construct a 'dummy' lattice, which consists of several copies of the real lattice; each copy corresponds to one energy. Before each copy I reset the Twiss parameters with TWISS command - since those are the same for different energies.
Then I set up the optimisation in such a way that the quad positions are kept the same for all copies (using co-variable), but strengths can be different.

Question1. Is there a better way to do this?
Question2. Ideally, I would like to optimise some beam parameters like emittance. So, in addition to setting the twiss parameters using TWISS command I'd like to reset beam parameters before each copy,
since otherwise phase space/emittance are very much distorted after each copy. Is that possible?

Please let me know if sth is unclear...

Cheers,
Slava

[michael_borland]

Slava,

Sorry for the long wait. I was on vacation.

I'm not sure it is exactly what you are trying to do, but attached is an example of matching a beamline for beams of two different energies. This would work, for example, for a multi-pass linac.

--Michael