floor coordinates with vertical deflection

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Liu_Weihang
Posts: 4
Joined: 28 Jun 2017, 07:12

floor coordinates with vertical deflection

Post by Liu_Weihang » 01 Apr 2022, 09:00

Hi everyone, I found in the calculation of the floor coordinates of the lattice that when there is a vertical deflection at the beginning, even if I supplement the deflection (i.e. Y=0, dY/dZ =0 ), Y will still change if there is a horizontal deflection after that. I don't understand why this is the case, I don't think the horizontal deflection will cause the Y to change. Can anyone explain this behavior?
Z-Y_end_in_horizontal bend.png
Z-Y_end_in_drift.png
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michael_borland
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Joined: 19 May 2008, 09:33
Location: Argonne National Laboratory
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Re: floor coordinates with vertical deflection

Post by michael_borland » 01 Apr 2022, 15:50

The reason is apparently that you introduce horizontal bending while the line is on a vertical slope. This introduces an effective roll of subsequent magnets.

To understand this, imagine that you have a vertical 90-degree bend followed by a normal 90-degree bend. In the second bend is defined in the vertically-oriented frame, so it results in the beam propagating horizontally again, but to the side. At the same time, the local coordinate system is rotated 90 degrees.

Looking at the theta (yaw), phi (pitch), and psi (roll) angles in the floor coordinate output files is helpful.

--Michael

Liu_Weihang
Posts: 4
Joined: 28 Jun 2017, 07:12

Re: floor coordinates with vertical deflection

Post by Liu_Weihang » 01 Apr 2022, 21:47

Dear Michael,
Thanks for the clean explanation.

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