Patent Number: 
Section: claims

1. A collimation apparatus comprising: a first collimation section made up of a plurality of first plate sets, each of said plates sets comprising plates of a radiation absorbing material and disposed in a fixed spatial relationship with respect to one another so as to define a respective passage between plates in a plate set, each of said passages defining a respective plate set longitudinal plane positioned equidistantly from the two plates in said respective plate set, said respective longitudinal planes of said plurality of respective first plate set passages intersecting at a line disposed a predetermined distance away from a front edge of said first collimation section; and  a second collimation section disposed adjacent said first collimation section, said second collimation section comprising a plurality of second plate sets comprising respective plates of a radiation absorbing material and disposed in a fixed spatial relationship with respect to one another so as to define a respective passage between plates in a respective plate set, each of said passages defining a respective plate set longitudinal plane positioned equidistantly from the two plates in said respective plate set, said respective longitudinal planes of said plurality of passages intersecting at a line disposed at said predetermined distance away from said front edge of said first collimation section,  said second collimation section being oriented orthogonal to said first collimator section in a fixed spatial relationship such that said line of intersection of said longitudinal planes of said passages of said first collimation section and said line of intersection of said longitudinal planes of said passages of said second collimation section intersect at a point at said predetermined distance, and such that radiation from a radiation point source located at said point is collimated in two orthogonal planes. 2. A collimation apparatus as recited in  claim 1  wherein said plates of said first collimation section and said plates of said second collimation section are retained in position by a plurality of brackets to secure said plates in position. claim 1 3. A collimation apparatus as recited in  claim 1  wherein said plates of said first and said second collimation sections comprises material selected from the group consisting of tungsten, lead, and natural uranium. claim 1