RFTMEZ0: on-crest phase depending on number of cells or cavity length?
Posted: 29 Oct 2019, 08:59
Hi Michael,
I want to work with the element RFTMEZ0 in order to investigate the phase slippage and to find the perfect acceleration process.
I noticed the following, what I do not understand: the on-crest phase seems to be dependent on the number of used cells (or cavity length). We use 20-cell Tesla-like cavities that are operated in pi-mode. To understand the element RFTMEZ0, I imported a 20-cell field map, a 2-cell field map and a 1-cell field map. They are simple test functions in the shape of 10 or 1 or 1/2 sine, respectively, as visualized in the picture. One cell is 0.05 m, hence 2 cells are 0.1 m and 20 cells are 1 m.
I used 10000 discrete points at each time, so the step size changes in the sdds files. The phase I have to adjust to accelerate on-crest depends on the number of cells (or the cavity length):
20-cell cavity: PHASE = 180°
2-cell cavity: PHASE = 0°
1-cell cavity: PHASE = 270°
(I converted the phases to rad in the lattice file).
Why is there a dependency on the number of cells (or on the cavity length) and what is the functional relationship?
I attached my files.
Thanks in advance,
Felix
I want to work with the element RFTMEZ0 in order to investigate the phase slippage and to find the perfect acceleration process.
I noticed the following, what I do not understand: the on-crest phase seems to be dependent on the number of used cells (or cavity length). We use 20-cell Tesla-like cavities that are operated in pi-mode. To understand the element RFTMEZ0, I imported a 20-cell field map, a 2-cell field map and a 1-cell field map. They are simple test functions in the shape of 10 or 1 or 1/2 sine, respectively, as visualized in the picture. One cell is 0.05 m, hence 2 cells are 0.1 m and 20 cells are 1 m.
I used 10000 discrete points at each time, so the step size changes in the sdds files. The phase I have to adjust to accelerate on-crest depends on the number of cells (or the cavity length):
20-cell cavity: PHASE = 180°
2-cell cavity: PHASE = 0°
1-cell cavity: PHASE = 270°
(I converted the phases to rad in the lattice file).
Why is there a dependency on the number of cells (or on the cavity length) and what is the functional relationship?
I attached my files.
Thanks in advance,
Felix