EG0700535 Energy and Spatial Angular Distributions of 252 Cf Gamma-rays Transmitted Through Iron, Graphite and Polyethylene Shields.

The transmitted angular and energy distributions of gamma rays resulting from exposure of slab material of iron, graphite and polyethylene to a collimated beam of Californium-252 neutron source have been measured. Gamma-ray spectra were measured by a neutron/gamma spectrometer with a stilbene scintillator and a pulse shape discrimination technique based on the zero cross over method. The obtained data are represented in the form of displayed gamma-ray fluxes and energy distributions at different angles behind samples of different thickness. The gamma flux decreases as the angle increases, and also decreases with the increasing of the material thickness for angles 0o and 15o, but slightly decrease for angles 30o and 45o. Secondary gamma rays produced from the investigated materials can be ignored compared with primary gamma rays, directly emitted from the irradiation cell. An empirical formula has been derived which relates the integral gamma flux with the sample thickness at different angles. Good agreement between measured and calculated integral gamma fluxes was obtained. The linear attenuation coefficients for gamma rays were derived both for the whole energy range and at different energies.