Programme stuck in superposed field maps

[shliu]

Dear Didier,

TraceWin got stuck in superposed field maps. I have attached the project file.

tst4field.rar

(114.99 MiB) Downloaded 8 times

I tried to run separate fields and it works, so I'm wondering if it's the problem of the input beam distribution.

Could you please help me to check it?

OS: Win11
Version: 2.33.4.2

Kinds,
shliu

[Didier]

Dear Shilu,

For the moment, I haven't found out why the code got stuck, but clearly it's linked to your initial distribution. Energy dispersion is the cause of the problem. Some particles can't get through the simulation planes because their energy is probably too close to 0.
I'm still looking and I'll let you know if I find anything.

Regards,

Didier

[shliu]

Dear Didier,

Thanks for the reply!

It works well if there's only one field map in the lattice:

DRIFT 0 250 0 0 0
FIELD_MAP 70 1600 0 250 325.509 0 0 0 Solb 0

or

DRIFT 0 250 0 0 0
FIELD_MAP 70 2635 0 250 -0.255442 0 0 0 Dipb 0

In the superposed field maps, the second field begins from 450 mm, but it stucks at 269 mm, which means that it doesn't reach the edge of the second field map.

I also tried beam initial distribution with narrow energy spread(εz/10 and βz*10) and it works.

I'm sure it is the problem with the low-energy particles in the input distribution, but the reason why it just stucks before the second field map is still unknown.

BTW, the "low-energy" particles are still at about 0.9 MeV, which is not so "low", when compared with the beam coming out from the iron source.

Kinds,
shliu