Simulations of a Spherical Section Electrostatic Analyser spaceweb@oulu.fi - last update: 20 August 2001 (JV)

The response function of a hemispherical electrostatic analyzer equipped with a curved aperture plate (to collimate the stray electric field at the entrance apertures) has been simulated. A cylindrical three-dimensional simultaneous overrelaxation algorithm has been introduced to solve for the stray field. The influence of the non-symmetric deformed hemisphere on the transmission properties of the hemispherical electrostatic analyzer was considered in order to explain the unexpected calibration results. It has been shown that using a specially selected deformation of the shape of the inner hemisphere yields a particle distribution which closely resembles the results of the calibrations. Thus, it can be concluded that the results of the simulations and the results of the calibrations are in good agreement with each other.