Abstract
An approach is made to the theoretical design of multichannel focusing collimators baed on the expression of Rotenberg and Johns for the minimum path length through the septa. Precise formulae for the number of holes and the efficiency of collimators with circular holes arranged in concentric rings are derived. A comparison is made with the results of the modified Beck theory. Calculations are extended to the case of multichannel collimators with holes of a segmented shape. Five such collimators have been fabricated, and their efficiency, calculated from their dimensions, agrees fairly well with experimental results. The relationship between the radius of the field of view and the experimentally-determined point source resolution is discussed.