The OPAL Discussion Forum

["Anastasia" <anastasia.ierides AT varian.com>]

Hello all,

As a tutorial, I am trying to model a linear accelerator as a beam line of
separate RF cavities rather than the whole LINAC geometry as one RFCavity
element. I have run the simulation both with a single RFCavity element and
with multiple cavities, wherein the dimensions are appropriately defined in
the field map files, such that the elements are right next to each other with
no space in between.

In the single element simulation, the refence particle electric field is
observed to depict expected behavior in the defined geometry, but in the case
of separate elements, there seems to be an additional “space” that is added
between the individual elements, extending the overall geometry to almost
twice the length. Could this be a mistake on my part in my input files, etc.,
or is there something in the code that by default forces this type of
behavior? For instance, in a situation where elements are too close together,
are they forced to have some minimal distance between them, etc.?

I guess the first question should be, does OPAL allow for the capability to
model a whole geometry as separate, yet connected RFCavity elements?

Any help in this would be greatly appreciated.

Thanks!