ZYLIND, Gamma Penetration for Cylindrical Source and Shield Geometry

1 - Description of program or function: ZYLIND is a point kernel program to calculate gamma-ray penetration for source/shield configurations with cylindrical symmetry. Dose rates are calculated for axial or radial detector positions behind layered shields of user - specified composition. Input data consist of source dimensions, compositions and thicknesses of shield layers, gamma-ray energies and source strengths. The code includes a data library of mass attenuation coefficients, buildup and dose conversion data. 2 - Method of solution: The three-dimensional point kernel volume integral for a cylindrical homogeneous source is calculated by Gauss integration. From the line-of-sight distance between point of integration and detector, mass attenuation and dose buildup are calculated, depending on the shielding materials characteristics. For each shield layer mass attenuation is determined from the actual elemental composition for the elements included in the built-in data library. Dose buildup factors are calculated recursively for subsequent layers according to Broder's formula. The coefficients for Broder's formula are interpolated in atomic number and energy for values not included in the library (Goldstein's data). The collided transmitted particle flux is multiplied by flux-to-dose conversion factors (interpolated in energy), taken from ESIS-Newsletter 34, July 1980, p.9. 3 - Restrictions on the complexity of the problem: A maximum of 20 energies 0.15 MeV...10 MeV and 8 shield layers can be processed. Mass attenuation coefficients for the following 24 elements and 3 materials are included: H, Be, C, N, O, Na, Mg, Al, Si, P, S, A, K, Ca, Fe, Cu, Mo, Sn, I, W, Pt, Tl, Pb, U, air, water, concrete. A maximum of 5 compositions of up to 10 of these elements may be specified. The number of integration points is fixed to 8 in each dimension and may not be adequate for extreme configurations. The distance from radial detector to source surface must exceed 25% of the source radius