Computer methods for electrostatic-field determination and ray tracing in image intensifiers (Q1803698)

The paper, published for the first time in 1969, gives a historical review of the methods used in that times for determining the trace of rays in electronic tubes in order to estimate the performance of image intensifiers. The digital approach of solution consists of two steps. The Poisson equation is approximated by finite difference equations, produced automatically from the data of the boundary contour, that are solved by the method of overrelaxation. From the approximately known potential the electron trajectories are calculated by means of a third order Runge- Kutta method with automatic step size control. The methods outlined have been used to aid the design of electron optic systems on an Elliot 503 computer. The limitations of that computer and the attained accuracy are discussed.