From Development of Improved Electron Optics For the 16 Inch Multiplier Phototube: "In order to derive a more efficient electrostatic optical system to be used in conjunction with a large area, 16 inch diameter multiplier phototube the following analysis has been made. This analysis is based on a similar optical system which is to be used in the design of a 16 inch diameter image convertor. At the end on the minifier, we reached the conclusion that the relaxation method constituted the best approach to the solution of the boundary value potential problem inside an axisymmetrical image convertor."