Noise reduction in crossed-field guns by cathode tilt

In this letter, noise studies of a short Kino gun with and without cathode tilts are described. It is found that for B/Bc≈ 1 there is a sharp increase in noise without any cathode tilt in a short Kino gun. For tilted cathodes noise appears only for B/Bc> 1. Two tilts have been investigated in order to study the relative effect. A tilt produces an extra component of magnetic field at the cathode surface in addition to the magnetic field in the conventional direction. With tilted cathodes the noise output is reduced by two orders of magnitude from that obtained from an untilted cathode in a short Kino gun.