Sextupoles chromatic correction

Moderators: cyao, michael_borland

Post Reply
Jafarinia
Posts: 23
Joined: 02 Nov 2017, 12:25

Sextupoles chromatic correction

Post by Jafarinia » 01 Apr 2020, 09:18

Hi Michael,

I am trying to use sextupoles for reducing emittance growth in the beam line after the dipole. Since there is dispersion (in x), I expect that sextupoles just affect the emittance growth in x. But both emittances decrease using these sextupoles while there is dispersion just in x not in y plane. In y plane without dispersion these sextupoles should work like quadupole that makes emittance growth.

I have attached the lattice and tracking files.

Thank you in advance,
Farzad
Attachments
ECN.png
ECN.png (7.43 KiB) Viewed 7810 times
Tracking.zip
(1.15 KiB) Downloaded 271 times

michael_borland
Posts: 1927
Joined: 19 May 2008, 09:33
Location: Argonne National Laboratory
Contact:

Re: Sextupoles chromatic correction

Post by michael_borland » 05 May 2020, 16:18

Farzad,

Theoretically, even for a thin-lens sextupole, there is a small change in the vertical divergence in going through a sextupole if there is horizontal dispersion and energy spread. So the emittance change you see is correct.

You can try it with a KSEXT element (which is a completely different implementation) and you'll get the same result.

--Michael

Post Reply