SKYNEUT evaluates the neutron and neutron-induced secondary gamma-ray skyshine doses from an isotropic, point, neutron source collimated by three simple geometries: an open silo, a vertical black (perfectly absorbing) wall, and a rectangular building. The source may emit monoenergetic neutrons or neutrons with an arbitrary spectrum of energies. The calculation of the skyshine doses uses the integral line-beam method which is based on a newly developed three-parameter approximation of the neutron line-beam response functions.

Source neutron energies must be between 0.01 and 14 MeV. For energies above 1 MeV, source-to-detector distances can be as great as 2500 m. For source energies below 1 MeV, the maximum source-to-detector distance is somewhat less.

The skyshine doses are expressed in units of dose equivalents (Sv) per source neutron based on one of the following three response functions: (1) the effective dose equivalent for AP irradiation of an anthropomorphic phantom, (2) the dose equivalent at 10 mm into the ICRU sphere for isotropic (ISO) irradiation, and (3) the dose equivalent on the principal axis at 10 mm depth for irradiation of the ICRU sphere by a plane parallel beam (PAR).

A users manual is provided in the publication: J.K. Shultis, R.E. Faw, and F.A. Khan, SKYNEUT: A Code for Neutron Skyshine Calculations Using the Integral Line-Beam Method, 19 pp., Report 9503, Institute for Computational Research in Engineering and Science, Kansas State University, Manhattan, KS, June 1995. This report, in Postscript and Adobe PDF formats, is also included in the distribution pakage provided here. P

Current version is 1.1, released January 5, 1998.