RFI Tutorial

There’s a lot going on in the RFI linac structure!  The attached cartoon
reveals many of its features. Double click    RFI-Tutor.exe    and
click the    RUN    button file to start the program.  Before proceeding,
shrink the screen input window to a short window at the top of the screen
so that it will not be in the way of the main event.

The RFI-Tutor program shows a scale representation of the 18 cells of the
RFI linac structure currently in our laboratory. Included is a description
of the phase of the fields in the gaps.

The screen input required are 3 integers: N1, N2, and Kontrol.
N1 and N2 are any numbers in the range from 1 to 18. I suggest
something like 5 to 12, although 1 to 18 shows the entire 18 cell RFI
structure that is in our laboratory. Kontrol = 7 shows all features.
Lesser numbers show some subsets of these features.

Once you’ve specified the input data, hitting “Enter” steps the action
through the linac, one third of a cell (60°) per hit.

Hitting "0" through "7" updates the Kontrol parameter for subsequent
program steps. Try hitting 0, 1, 3, and 7, interspersed with some
"Enters" hits, to see a progression of features.

Hitting any key (except "0" through '7') returns you to the N1/N2 question.

The beam starts in the center of a gap. 60 deg later, it is in the center
of the RFI focusing lens, 60 deg later all the electric fields are zero
(changing sign) and the beam is drifting, and 60 deg later the beam is
in the next gap for further acceleration. In this tutorial you see all of
these locations.

The quad sequence is - + + - , beginning with cell #1. The polarities
are labeled. Note that the bore hole is larger in the “+” lenses. This
is a result of the elliptical lenses that I plan to use. Notice that the
beam is also larger in the “+” lenses (a general feature of alternating
gradient focusing).

There are 10 Notes calling attention to some observables. These start
showing up after 10 "Enter" hits and continue for until finished.

I hope you’ll play with this for a few minutes and observe some of these
interesting features.