Round dipole

[SchroederSa]

Hi,

A question:

Is there a way to simulate a round pole dipole?

Best
Sarah

[sergey-tomin]

Hi, I didn’t know that such magnets exist. What are they used for? do you have a reference?
Just looking at the geometry, I would assume it has an edge quadrupole and sextuple components. Isn’t that the case?
If we’re talking about linear optics, I assume you can calculate the position of the ideal beam and find the beta angles (as shown in the picture you attached), which would give you the linear matrix. To track the beam through the magnet, we’d need to implement the R and T matrices if you have them, or alternatively, you can use the RK integrator embedded in Ocelot.

[st-walker]

Can something similar and relatively simple be achieved with sbend and h_pole1/h_pole2 perhaps?

[sergey-tomin]

You’re right. I forgot that it’s already included. Although I have never used it.
It is in docstring in ocelot.
h_pole1 - the curvature (1/r) of the entrance face
h_pole2 - the curvature (1/r) of the exit face

[SchroederSa]

Thanks for your quick help.

We use such a dipole as an electron spectrometer. References would be:

https://escholarship.org/uc/item/98h5r889

If I understand it correctly, such a design minimises edge focusing. The beam enters and exits the pole at the exact same angle.

[st-walker]

I only very briefly looked at the paper, fig 3 shows this "wedge" magnet, I guess this is same as using h_pole1/hpole_2 in ocelot. So I suppose it's different to a truly round magnet.

Instead, can you just take the matrix in Equation 5 and use ocelot.cpbd.element.Matrix?

[SchroederSa]

The paper discusses two dipoles, a round one and a wedged (Pacman) dipole.

Thanks for your help and ideas, I will give it a try and report. I have never used the Matrix element, I will take a look - thanks!

Sarah