Search found 33 matches

by gwei
16 Mar 2021, 02:42
Forum: Momentum Aperture
Topic: Momentum aperture in a two energy storage ring
Replies: 6
Views: 15510

Re: Momentum aperture in a two energy storage ring

Hi Michael, I am having trouble to calculate the momentum aperture and Touschek's lifetime in a two-energy storage ring. We have two rings connected through SRF cavities. Low energy ring (150 MeV) and High energy ring (1000 MeV) are connected by SRF cavities which first accelerates the beam and the...
by gwei
15 Mar 2018, 16:16
Forum: Ring Tracking
Topic: Tune difference between MADX and ELEGANT when we have decouping section?
Replies: 13
Views: 6053

Re: Tune difference between MADX and ELEGANT when we have decouping section?

Hi Michael, Thank you so much. And I think Dynamic aperture is OK with coupling section for a ring lattice because &find_aperture(as follow) is based on track. Is it right? Thank you again. guohui &find_aperture output = "%s-check.aper", mode = n-lines, n_lines = 41, xmin = -0.0015, xmax = 0.0015, y...
by gwei
15 Mar 2018, 15:56
Forum: Ring Tracking
Topic: Tune difference between MADX and ELEGANT when we have decouping section?
Replies: 13
Views: 6053

Re: Tune difference between MADX and ELEGANT when we have decouping section?

Thank you, Michael,

But even with emittances_from_twiss_command = 0, there is no output also.

Guohui
michael_borland wrote:
15 Mar 2018, 15:49
Guohui,

Sorry, my mistake. Add

Code: Select all

emittances_from_twiss_command = 0
to the &coupled_twiss_output command.

--Michael
by gwei
15 Mar 2018, 15:47
Forum: Ring Tracking
Topic: Tune difference between MADX and ELEGANT when we have decouping section?
Replies: 13
Views: 6053

Re: Tune difference between MADX and ELEGANT when we have decouping section?

Hi Michael, I add the your suggested lines of &coupled_twiss_output to the .ele file as attached. But when I run it, it gives a error information as follow. emittances_from_twiss_command was set but twiss calculations not seen Thanks. Guohui Guohui, &twiss_output assumes that the lattice is uncoupl...
by gwei
15 Mar 2018, 15:46
Forum: Ring Tracking
Topic: Tune difference between MADX and ELEGANT when we have decouping section?
Replies: 13
Views: 6053

Re: Tune difference between MADX and ELEGANT when we have decouping section?

Hi Michael, I add the your suggested lines of &coupled_twiss_output to the .ele file as attached. But when I run it, it gives a emittances_from_twiss_command was set but twiss calculations not seen Thanks. Guohui Guohui, &twiss_output assumes that the lattice is uncoupled. The beta functions etc. ar...
by gwei
15 Mar 2018, 15:34
Forum: Ring Tracking
Topic: Tune difference between MADX and ELEGANT when we have decouping section?
Replies: 13
Views: 6053

Re: Tune difference between MADX and ELEGANT when we have decouping section?

Thank you very much, Michael. Guohui, &twiss_output assumes that the lattice is uncoupled. The beta functions etc. are computed from the 2x2 submatrices for the x and y planes. So stritly speaking they are not correct anywhere in the presence of coupling. You can compute the coupled twiss parameters...
by gwei
15 Mar 2018, 13:19
Forum: Ring Tracking
Topic: Tune difference between MADX and ELEGANT when we have decouping section?
Replies: 13
Views: 6053

Re: Tune difference between MADX and ELEGANT when we have decouping section?

Hi Michael, Thank you very much. By the way, how did you calculate tune in $twiss_output? And are beta_x, alfa_x right in the output of $twiss_output? Or in the output of $twiss_outputare, are beta_x, alfa_x right in decoupling section in the lattice, but wrong in the coupling section? As you know, ...
by gwei
15 Mar 2018, 09:00
Forum: Ring Tracking
Topic: Tune difference between MADX and ELEGANT when we have decouping section?
Replies: 13
Views: 6053

Re: Tune difference between MADX and ELEGANT when we have decouping section?

Michael,

I have email them to you.
Thank you.

Guohui
michael_borland wrote:
14 Mar 2018, 16:25
Guohui,

I would need to see the lattice file to comment. Can you upload it?

--Michael
by gwei
14 Mar 2018, 16:00
Forum: Ring Tracking
Topic: Tune difference between MADX and ELEGANT when we have decouping section?
Replies: 13
Views: 6053

Tune difference between MADX and ELEGANT when we have decouping section?

Hi Micheal,

I find a tune difference in a collider ring lattice between MADX and ELEGANT.
The collider ring has two decoupling section. This cause a different tune output from the two CODE.
It is right?

Thank you.

Guohui
by gwei
22 Nov 2017, 14:24
Forum: Dynamic Aperture
Topic: An interesting problem in a tune footprint of FMA
Replies: 7
Views: 13696

Re: An interesting problem in a tune footprint of FMA

Guohui, Thanks for sending the lattice. One problem is too few kicks for the quadrupoles. Some of your quadrupoles are quite long and not weak, so the lattice functions can change considerably inside them. This means you need more kicks to get a good model. I got tunes of 0.219 and 0.160 by increas...