A modified mass reflectron

The paper offers a new electron-optical circuit for a three-component mass reflectron. It consists of two drift spaces separated by a double electric layer and a single parallel-plate electrostatic mirror-condenser. The double layer in the actual construction is replaced with two closely-spaced small grids formed by a set of parallel metal wires. This scheme provides the third order energy focusing at low 4th order aberrations. A consistent analytical theory of such a modified reflectron is developed, and it is shown that the proposed version is optimal as compared to a general triple-mirror reflectron.