A CRT that stores 400 MHz transients

This paper describes the design of the high speed storage CRT used in the Tektronix 7834 oscilloscope. This CRT is capable of storing single events at 400 MHz and utilizes an electron gun which employs quadrupole lenses to achieve scan expansion and focus of the beam. An improved collimation system is used which achieves a more uniform display of the stored signals. The design of a large collimation lens is described in terms of a separation of variables solution of the potential distribution in cylindrical coordinates. Design equations are given for quadrupole electrostatic lenses and aberrations of such lenses are discussed. A technique was found for correcting the dominant aberration terms by the use of octapole lens fields. A comparison with the previous state-of-the-art is given.