emittance and CSR optimization
Posted: 09 Feb 2012, 16:27
Dear elegant folks,
I have 3 deflecting cavities in a line (CAVON1CAVON,CAVON2). These three cavities are between two dogleg section. I want to use elegant for optimizing the phase and strength of these cavities such that it satisfies two conditions (i) difference between the outgoing emit x and incoming emit z is minimized (ideally should be zero) and (ii) difference between the outgoing emit z and incoming emit x is minimized (again, ideally difference should be zero) as this is an emittance exchanger. And both of this with CSR turned on.
The problem starts to become difficult if I turn on the CSR at the dipoles (four of them). So two questions:
(i) What is the optimization term that I use to do the above?
(What I am currently doing is in the attached but I do not know how to extract incoming emittance from a FITPOINT (MATCH1). Doing
MATCH1#1.enx el 3E11 pCentral * / - sqr gives me an error??? MATCH1 is a point just before the emittance exchanger and MATCH2 is a point after the exchanger. So I have hard coded it in for now. I am sure there is a "guru-like" solution.
(ii) More importantly, how do i speed up the optimization with CSR on? Any suggestions (other than reducing the BINS SIZE )? It takes me hours to run and program just hangs. I am bit suspicious that i may be doing something wrong. For instance, if I optimize the program with a single particle with CSR off and then use those values to run with CSR and say 10K particles, then the emittance numbers go crazy. Is there a smarter way of doing this? Thank you..
Since the CSR emittance growth is overestimated in elegant, I want to use elegant to get confidence on the upper limit.
regards,
Charles
I have 3 deflecting cavities in a line (CAVON1CAVON,CAVON2). These three cavities are between two dogleg section. I want to use elegant for optimizing the phase and strength of these cavities such that it satisfies two conditions (i) difference between the outgoing emit x and incoming emit z is minimized (ideally should be zero) and (ii) difference between the outgoing emit z and incoming emit x is minimized (again, ideally difference should be zero) as this is an emittance exchanger. And both of this with CSR turned on.
The problem starts to become difficult if I turn on the CSR at the dipoles (four of them). So two questions:
(i) What is the optimization term that I use to do the above?
(What I am currently doing is in the attached but I do not know how to extract incoming emittance from a FITPOINT (MATCH1). Doing
MATCH1#1.enx el 3E11 pCentral * / - sqr gives me an error??? MATCH1 is a point just before the emittance exchanger and MATCH2 is a point after the exchanger. So I have hard coded it in for now. I am sure there is a "guru-like" solution.
(ii) More importantly, how do i speed up the optimization with CSR on? Any suggestions (other than reducing the BINS SIZE )? It takes me hours to run and program just hangs. I am bit suspicious that i may be doing something wrong. For instance, if I optimize the program with a single particle with CSR off and then use those values to run with CSR and say 10K particles, then the emittance numbers go crazy. Is there a smarter way of doing this? Thank you..
Since the CSR emittance growth is overestimated in elegant, I want to use elegant to get confidence on the upper limit.
regards,
Charles