The Oblique Image Converter

Publisher Summary This chapter describes the various aspects of the oblique image converter. The oblique electromagnetic lens (OEL) consists of plane parallel object and image surfaces immersed in homogeneous and steady-state electric and magnetic fields that are perpendicular and oblique to the object and image surfaces respectively. The principle of operation of the oblique electron lens is that electrons which leave the object plane are accelerated by the electric field, and deflected and focused onto the image plane by the oblique magnetic field. The displacement of the electron optical image results from the electron acceleration in the direction of the magnetic field and the constant cross field drift, velocity. The photoelectrons are deflected and focused by the OEL onto an electron target at a distance from the input optical axis. The radius of the input window will generally be larger than the output window radius to accommodate the light bundle. An experimental ultraviolet sensitive oblique image converter is being developed, which employs a magnesium fluoride input window, an opaque caesium iodide photocathode, a P-20 phosphor screen, and a fiber optic output faceplate. It is found that veiling glare and signal induced background effects can probably be held to very low values because of the offset nature of the oblique electron lens.