This example describes a beam deflection element. It builds on a previous example, illustrating generation of a uniform transverse electric field in a long cylindrical pipe. There are three extensions:
- Treatment of a finite-length pipe with a 3D field distribution.
- Calculation of charged particle trajectories to determine the deflection uniformity.
- Input definitions for macroparticles, with much higher mass and charge than electrons or ions.
The electrode array, shown in the upper figure, consists of 12 0.4 cm diameter rods of length 3.0 cm uniformly arrayed on a circle of radius 1.1 cm. The applied voltages follow a cosine variation with angle.
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Results
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The central figure of equipotential lines in the plane z = 0.0 cm illustrates that the electric is approximately uniform in the central region and directed along the x axis. The lower figure shows trajectories of macroparticles projected to the plane y = 0.0 cm for a peak applied voltage of 750.0 V. The incident beam of radius 0.7 cm consists of particles with the following parameters: M = 3.35E-11 kg, Q = 1.0E-12 C and velocity V = 40.0 m/s. The deflection angle averaged over 560 model particles was 0.05435 +- 0.001 radians.
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Comments
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This tutorial gives a complete description of the theory and results: Modeling an electrostatic macroparticle beam deflector.
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