title: Modulation transfer function of image tube lenses.
abstract: The modulation transfer function (MTF) of the proximity focusing biplanar lens and the sharp focusing electrostatic and electromagnetic lenses is derived and presented. It is shown that for a Maxwellian emission energy distribution, the MTF of the biplanar lens is MTF = exp(-4pi(2)epsilon/V(s)L(2)F(2)), where L is the screen to cathode separation in mm, f is the spatial frequency in lp/mm, V(s), is the screen voltage, and epsilon is the voltage equivalent of the most probable emission energy. For a cosine distribution, the MTF of the biplanar lens is MTF = exp(-7 piepsilon/V(s)L(2)f(2)). The MTF of sharp focusing image tube lenses is MTF = exp(-0.06pi(2)epsilon(2)M(2)f(2)/E(c)(2)), where E(c), is the cathode field strength in volts per mm and M is the magnification. In general, the MTF of image tube lenses is MTF = exp[-(pirhof)(2)], where rho is the focusing error coefficient of a particular lens.
authors.forename: I P
authors.initials: IP
authors.lastname: Csorba