|Message: Re: Ion beam disappears entering in quadrupole field||Not Logged In (login)|
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> > > This is only true if you positioned the quadrupole (logical) volume > without rotation or you rotate only around z. In all cases where you > rotate around x and/or y the two don't coincide. > Yes, the quadrupole is set without rotation, then I suppose that the z-local-axis coincide with the z-global one, Being z the beam axis. > If you rotate around Z, all you are doing is rotate the quadrupole > around its length axis. Is this what you want? Yes, in order to simulate a quadrupole triplet, I need three quadrupole fields. The quadrupole in the middle of the triplet is rotated 90 degrees in z-axis relative to the other two. The three quadrupoles are different instances of the same class, differing just in that angular argument when constructed. > Well, shouldn't 'Rot' not be 'trip_rot'? > I'm sorry, in order to save space in the latter post I have edited the code then I pasted wrong. Let's say: Rot = trip_rot > > Why anti-intuitive? If you want the axis of the quadropole away from the > global z-axis but still in the horizontal plane, how do you have to > rotate a lengthy box (in real live)? ... around y! I suppose that the G4QuadrupoleMagField class was made by Geant4 in order > to focus/rearrange beams in accelerator experimental beamlines, and if > true, the z-axis should be the default axis of the beam to focus, (because > is clear that the three main-axes of the quadrupole are not equivalent)... > Then, seems to me a little anti-natural to needing to rotate the quadrupole > in the other axes (X and Y)... But if I'm wrong, maybe X (or Y) the default > axis (or even an non orthogonal one) for the beam. > > [ MIME part of type text/html without a name stripped ]
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