Tracking with dipole field map

[comunian]

Dear Didier,

we try to simulate a tracewin line from 2021, which contains two dipole fieldmaps which perfectly worked in the past Tracewin version. However we noticed that, with the new versions, we had some losses inside the dipoles, apparently because all positive energy particles are canceled from computation, in the field map.

In order to investigate the issue, we simplified the project (downlodable at the link), and, inputting a kind of zero-emittance macro-particle, we noticed a very strange trajectory in the fieldmaps, precisely at the end of the two dipoles, a kind of kick which was not present before. We are using the same magnetic factor we were using since 2021. The beamlet does not anymore follow the synchronous particle, for some reasons.

We checked with different project and it happened the same phenomena (losses with higher emittance, steering when using the beamlet). Could please you help us?
Best Regards,
Michele Comunian