English: The top of the Cockcroft-Walton generator that provides the initial acceleration for particles in the Zero Gradient Synchrotron at the US Argonne National Laboratory in Chicago, Illinois, examined by Albert Crewe (right), Argonne director from 1961 to 1967. The Cockcroft-Walton is a circuit consisting of capacitors and diodes that multiplies a lower AC voltage to produce a high DC voltage at the top shown which is used to accelerate the particles. The shape of the high voltage terminals must be smooth with large diameter curves to prevent corona discharge, an ionization of the air that can cause the charge to leak off.