Minimizing maximum beam size in a lattice

[libov]

Michael,

I'd like to optimize the lattice in such a way that the maximum beam size along the whole lattice is not exceeding a certain value.
Just minimising beta function won't work (I'm dealing with beams having large energy spread) so I really need access to beam size from tracking.

Is there a built-in possibility to do this? I mean, something similar to what one can do with the beta function (i.e. max.betax will find a maximum of betax in the whole lattice)

One less convenient option I see is to use several MARK element along the lattice and to use Sx or Sy at each occurence in optimization_term.

Before doing that I thought it's a good idea to ask you whether there is an easier way.

Thanks in advance for your time!

Slava

[michael_borland]

Slava,

Unfortunately, there are no statistics for beam sizes, so using MARK elements is the only possibility for now. There are some things you can do to make this easy:

Use &insert_elements to add many markers with the same name:

Code: Select all

&insert_elements
        name = *
        element_def = "M1: MARK,FITPOINT=1"
&end

This will insert a marker named "M1" after every element.

Then, use the following command to add the optimization terms

Code: Select all

&optimization_term
  term = "M1#@.Sx sqr", 
  field_string = @, 
  field_initial_value = 1, field_final_value = 1000, field_interval = 1
&end

This will create optimization terms for Sx^2 at 1000 M1 elements, starting from occurrence 1.

--Michael