CEA Codes forum

Dear Didier,

I found issues related to beam phase when doing a single error run. In short, it seems that

- set_beam_phase_error command seems nor working in recent versions.
- There is something strange in the synchronous phase plot for a single error run. (Only for the partran result. Plot for the envelop looks fine.)

Please fine that the attached zip contains two projects (for a DTL with 3 tanks). In the reference project, the phase of the 1st gap is shifted by +15 deg by hand (the rest of the gaps are in the phase-mode 3) and the synchronous phase oscillate as seen in sync-phs_ref.png. In the other project, the same effect was introduced by an error command. The error is applied only to the 1st tank and the beam phase error is canceled for 2nd and 3rd tanks. As seen in sync-phs-err_envlp.png, the phase errors seem not canceled at the entrance of the 2nd and 3rd tanks. sync-phs_err_partran.png shows the result of partran for the same project. We can see that the results between envelop and partran are very different. (Thought looking at the phase centroid oscillation in the density file, the transport calculation seems done correctly.) Finally, sync-phs_err_envlp_old-ver.png shows the result from the same project, when running with a very old version (2.18.6.1). We can see that the result is identical to the reference case.

Hope this is clear enough. Thanks for your help in advance.

/Ryoichi

Dear Ryoichi,

Both problems have been solved.

Regards,

Didier

Dear Didier,

Thanks a lot for the prompt fix as usual. Although one minor thing is remaining. SET_BEAM_PHASE_ERROR command used to act on the location of the command, but now it seems acting at the exit of the following element. Is this the intended behaviour?

In the attached very simple example, I'm introducing an error to the first 3 gaps and then canceling the error for gaps #4-#6.
- Running the lattice "lat_without-zero-drift.dat", I get "test-set-beam-phs-error_without-zero-drift.png" as the sync phase and the sync phase at the 4th gap (around 0.3 m) still has an error.
- On the contrary, running the lattice "lat_with-zero-drift.dat", which has a zero drift before the 4th gap and after the SET_BEAM_PHASE_ERROR, I get "test-set-beam-phs-error_with-zero-drift.png". For this one, the sync phase at the 4th gap has no error.

Please kindly let me know if you want to keep the old way or this is how the commend is meant to work from now on.

Best regards,

/Ryoichi

Dear Ryoichi,

it's fixed.

Regards,

Didier