Calculations were performed to determine energy and angle distributions of the fission-product gamma ray, air-ground secondary gamma ray, and neutron fluence incident on structures resulting from the detonation of a representative intermediate-yield thermonuclear weapon 100 m above the ground. These energy and angle distributions were used as input data to the ANISN discrete ordinates code to calculate the penetration of the radiation through various thicknesses of type O-HW1 concrete. The production and transport of concrete capture gamma rays were calculated in tandem with the neutron transport. The penetration results were used to calculate the various radiation components at the center of a simple concrete blockhouse. The inside lengths and widths of the structure varied from 10 to 50 ft and the inside height was fixed at 10 ft. Wall and roof thicknesses varied from 6 to 60 in. The results of the calculations were expressed as structure protection coefficients (dose at the receiver per unit free-field dose). The neutron dose was found to contribute the highest fraction of the total dose for wall and roof thicknesses up to 12 in. For thicknesses of 18 in. and more, the airground secondary gamma rays and concrete capture gamma rays were found to dominate, becoming increasingly more important with increasing thickness. The relative magnitude of each component did not vary significantly with structure size; however, all components were found to decrease with an increase in structure size for a given wall and roof thickness.
