Magnetic lens

QuickField simulation example

Magnetic lens is used for electron beams focusing.

Engineering question
How to find magnetic lens electron beam focusing field?

Engineering answer
Set up an axisymmetric QuickField DC Magnetics problem for a magnetic lens and evaluate electron beam focusing field from computed field results.

Typical applications
magnetic electron lenses, beam focusing magnets, vacuum beamline optics

• Download simulation files (files may be viewed using any QuickField Edition).

Problem Type
Axisymmetric problem of DC magnetics.

Geometry

Given
Relative permittivity of vacuum ε = 1;
Coil current I = 10 A.
Relative permeability of the core μ = 1000;
Charge (electron) q = -1.602e-19 C
Mass (electron) m = 9.109e-31 kg
Initial velocity v_y = 300 km/s, v_z = 1000 km/s.

Task
Calculate the charged particle trajectory.

Solution
Particle trajectory may be calculated using the free tool TrajectoryTracer.

Results
Final velocity v_y = 2.2 km/s, v_z = 1000 km/s.

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