Analytical calculation of the solid angle defined by a cylindrical detector and a point cosine source with parallel axes

Abstract

We derive analytical expressions for the solid angle subtended by a right finite circular cylinder at a point source with cosine angular distribution in the case where the source direction is parallel to the cylinder axis. As a subsidiary result, an expression for the solid angle subtended by a disc detector at a spread disc source is also provided, in the case where the two discs have a common symmetry axis which is also coincident with the source direction.

14 pages, 7 figures, Latex. Changes in version 2, which was accepted for publication: references added, two new sections (2.3 and 2.4) included. A discussion on the interplay between numerical and analytical methods was added to the introduction. No errors were found in the prior version