Effects of Elastic Distortion of Rotating Mirrors on Time Resolution in Smear Cameras*

Abstract

The basic relations for the rotating mirror smear camera are reviewed and expressions are obtained for the maximum time resolution obtainable in systems uncorrected for the elastic distortion of the mirror surface. Instrumentation for the measurement of the surface distortion at high speed is described and data are reported for rotating rectangular parallelepipeds as a function of size and width-to-thickness ratio. The central sections of the mirrors deform cylindrically, the power varying nearly with the square of the peripheral speed. The distortion effects can be almost completely compensated by the introduction of negative astigmatism into the system. An auxiliary optical system is described which aids in the adjustment of the corrector lens to obtain optimum resolution. A corrected system in current use has a time resolution of 10-8 sec with relative aperture ƒ6.