A secondary electron energy analyzer employs a pair of spaced coaxial cylinders with entrance and exit slots in the inner cylinder, the distance between the slots and the potential between the cylinders being such that secondary electrons emitted from a specimen located at a point on the axis of the cylinders enter the space between the cylinders at the entrance slot and are focused at the exit slot. An electron multiplier is located within the inner cylinder to receive the focused electrons. The outer cylinder may be split into two portions, each with its individual slots and operated at slightly different potentials, so that electrons of different energies are focused at the two exit slots, measurement of the difference in the outputs from the two portions yielding the derivative of the energy distribution curve of secondary electrons.