To control a particle beam inside a particle accelerator, accurate information about the beam position is of prime importance. A so-called particle beam position monitor can be used to obtain this information. The particles that move in the accelerator generate an electric field that is measured by four electrodes. This measurement, combined with further calculations, leads to the detection of the beam position with high accuracy.
This beam position monitor consists mainly of a cylindrical device. Four coaxial structures guide electromagnetic waves to voltage monitors. Each two of these structures are on opposite sides of the cylinder. The ports absorb the electric and magnetic fields. A particle beam with a total charge of 1e-9 C and with a velocity of the speed of light is defined on the axis of the cylinder.
The solver setup is simple. In the wakefield solver dialog box, the "Simulated Wakelength" should be set to 500. Then, one can start the solver.
To calculate the absolute value and the argument of the transfer function, several result templates are defined. The template results are located in the folder "Tables" of the navigation tree. In the folder "1D Results", the port signals and the monitors' voltage signals are available. The wakefield results can be seen in "1D Results\Particle Beams".