CEA Codes forum

Dear Didier,

For some reason, the phase advance charts for my linac do not seem to plot past z=57 m correctly. It might have something to with a ~short transport section that starts around there, but I'm not sure. What do you think is going on?

I have attached the phase advance plots below. I will send you my TraceWin project files separately.

Thanks,

Josh Y.

Dear Josh,

Using your file I got following plots, that seems correct !

Regards,

Didier

Hi Didier,

I'm not sure how you got those charts. When I try to plot the deg/m phase advances (abscissa=meter, ordinate=meter, phase advance = structure or beam), I get the following plots. I've also attached the associated ascii files. Did you modify the files in some way to get them to plot correctly?

Thanks,

Josh

Dear Josh,

No I change nothing, please try to reload the code, perhaps I made some corrections without changing the version number and lets me know

Regards,

Didier

Dear Didier,

I tried deleting and redownloading the Tracewin.exe file...I guess it got corrupted somehow. I get the correct plots now.

Thanks!

Josh

Hi Didier,

One other thing: I was wondering why at certain points along the linac, most notably around z=4.62 m and z=16.4 m, the k0 phase advance is calculated as 0? These seem to roughly coincide with the last elements in sections 1 and 2 in my linac.

Thanks,

Josh

Dear Josh,

The calculation of k0x is based on an arcos function, which must obviously be less than 1; however, for period #8, given that your solenoid has a very weak magnetic field, this value is greater than 1, preventing the phase advance from being calculated (see below for phase advance definition used in TraceWin).
I suppose it’s the same issue for the other period where the phase advance is set to 0

https://dacm-codes.fr/Softwares/TraceWi ... definition

Regards,

Didier