Quasi-Uniform Irradiation of Plane Surfaces Using Multiple Radiation Sources

The question of the optimum location of multiple radiation sources for quasi-uniform irradiation of plane surfaces is addressed, and the problem is studied numerically for the case of a square plane target surface and plane arrays of equal spherically symmetric (4π) radiation sources. The technique presented is also applicable to non-planar source arrays and non-planar targets as well as to the case of sources whose radiation pattern is not spherically symmetric. The square target problem is solved numerically for the case where the desired target surface flux uniformity is 80%. The optimum source location coordinates and the resulting target flux patterns are presented for a number of source arrays. The scaling with the number of sources used and the distance between the source and target planes is also given. The results show that a significant reduction in the total source strength required to produce a given quasi-uniform target fluence can be achieved by using multiple sources. For example, for an 80% uniformity constraint, four properly placed sources, So, are found to give ~19 times the average flux from a single source of strength So. This represents a gain factor of ~4.76 due to better utilization of the available source strength. Calculations show that gains in excess of an order of magnitude can be achieved in this manner by using a large number of properly placed sources.