IBSCATTER with ILMATRIX gives wrong Horizontal Emittance
Posted: 12 Apr 2021, 10:20
Hi,
I am trying to model a ramping booster using an ILMATRIX + SREFFECT element with IBS effects included via the IBSCATTER element.
In all cases I have tried, the horizontal emittance seems to scale, if at all, inversely proportional to the bunch charge. If I track using element-by-element tracking I get the expected scaling.
Strangely, the vertical and longitudinal emittance scale correctly. This is also true if I include COUPLING in the SREFFECTS element.
I have included an example of the ILMATRIX based tracking, and a few pictures, comparing the ILMATRIX (dashed lines) vs. element-by-element (solid lines) tracking, to show the scaling going wrong only for the horizontal plane. I tried moving around the order of the elements, but nothing seems to change the results.
Cheers,
James
I am trying to model a ramping booster using an ILMATRIX + SREFFECT element with IBS effects included via the IBSCATTER element.
In all cases I have tried, the horizontal emittance seems to scale, if at all, inversely proportional to the bunch charge. If I track using element-by-element tracking I get the expected scaling.
Strangely, the vertical and longitudinal emittance scale correctly. This is also true if I include COUPLING in the SREFFECTS element.
I have included an example of the ILMATRIX based tracking, and a few pictures, comparing the ILMATRIX (dashed lines) vs. element-by-element (solid lines) tracking, to show the scaling going wrong only for the horizontal plane. I tried moving around the order of the elements, but nothing seems to change the results.
Cheers,
James