Properties of Periodic Gas Lenses

Gas lenses are being considered as focusing elements of beam-waveguides. Since very many lenses are needed to form a long waveguide, it is reasonable to consider periodic arrangements of gas lenses. Such periodic structures might operate with a gas stream which flows through all of the lenses in succession. A periodic temperature distribution in the gas results which is different from that of single gas lenses considered in two earlier papers.3,4This paper analyses the ray optics properties, such as focal length and principal surfaces of the gas lenses, of two types of alternating gradient focusing systems. One system consists simply of a succession of hot and cold tubes. The other system results from the first by insertion of heat insulating tubes of equal length between the hot and cold tubes.