Elegant users forum

Dear Michael，

I got the answer of my previous post.
Change KQUAD element to Quad and limit transfer matrix order to 1. The emittance growth in linac is gone.

Thanks a lot.
yours Chao

Dear Michael, Thanks a lot for your reply, and I need your help of one more thing, which related to the emittance growth in the linac. As discussed in the previous post, I am now cutting the cavity into sub-parts and inserting quadrupoles in between to model the overlapping between cavity and quadru...

Dear Michael Thanks for a nice discussion. I think I got it. There is one more question I need you help. It relates to the subject we discussed. At this moment, I am prepare to simulate a linac. Unfortunately, on top of the cavities, there are some quads, which mean there existing element overlappin...

Chao, The kick algorithm is drift-kick-drift, which is a higher-order integration than kick-drift (O(h^2) vs O(h)). If N_KICKS=0, an analytically-derived transfer matrix is used. That matrix assumes ultra-relativistic motion, which gives constant phase. --Michael I see, which means if n_kicks=50, t...

Dear Michael, Thanks for your replying. However, I have to ask one more round to confirm my understanding. "The RFCA element is a special case of the RFCW element, using the same code for simulation of the accelerating fields." and "The N_KICKS parameter, if non-zero, for RFCA/RFCW controls the numb...

Hi Michael, I am trying to simulate a linac with the elegant. The travel cavity is modeled by the element RFCW. There are several questions hopefully you can help me. 1, Assume I have a 50 cells in total, in the RFCW, which parameter in this RFCW element give the information of number ofcells in tot...

Dear Michael, Great thanks, I do have a better understanding the cavity feedback model in elegant. I have one other question about the impedance beam can sample when the feedback comes into the system, because of that both the transient beam loading effect and the longitudinal both instability are r...

Dear Michael Great thanks. It gives me really a better feeling about the modelling of the cavity feedbacks. There is another thing about the cavity feedback. I found that in the filter file AmpFeedbakcFilters.sdds It includes two pages and each page representing one digital filter. As written in the...

Dear Michael In the past days, I spent some time to go back to the papers on the low level rf control and cavity state-space theory. Now I think I get a better understanding on your IPAC15 paper about rf-feedback in rfmode element. Still, I would like to discuss a little bit to make sure my understa...

Dear Michael Thanks for your nice discussion and suggestion. I did not know valgrind before. And I looked into it during the past days. It is a very nice tool. I also look into my code again. All of a sudden, I realize my average process to get the average voltage vector in polar coordinate system i...