madx adaptor appears to make all quadrupoles have positive strength
When a madx lattice is read in and converted into a chef beamline, the strength of all the quadrupoles is positive, at least as shown by synergia.lattice.chef_beamline_as_string(). This isn't the full story though. The beamline behaves as if the negative strength quadrupoles are present since it is stable and has sensible tunes.
#1 Updated by Eric Stern about 6 years ago
- Status changed from New to Resolved
What was happening was that to accommodate k1s components in the madx adaptor, all quadrupoles were being implmented as potentially rotated positive strength quadrupoles. Commit e413a016d638879bc73107c08fb710603c32a993 changes it so that if k1s==0.0 the original k1 strength is retained and there is no rotation, so the CHEF element will indeed have a negative strength.