Gamma Ray Penetration Experiments For A Light Aircraft Carrier Using Distant Sources And Sources Simulating Contamination Of The Hull

Gamma-ray Penetration Experiments for a Light Aircraft Carrier Using Distant Sources and Sources Simulating Contamination of the Hull

The penetration of gamma rays into compartments of an aircraft carrier from two different radioisotopes was measured in two different experiments. In one experiment, cobalt-60 and cesium-137 point isotropic sources were exposed near the hull of the ship to simulate hull contamination. Measurements of dose were made in the forward part of the ship at four different deck levels. Dose distribution data are presented for the two sources used and for the different source points considered. In the second experiment, nominal 500-curie collimated cobalt-60 source was exposed at a distance of roughly 100 feet from designated points to irradiate two general regions of the ship. Dose distributions are presented for each of 18 different source positions used. Five decks were in instrumented in each of the two general regions considered. Diagrams indicating source positions, and hull-plating thicknesses are also presented.

The Effect of Source Distance on Buildup Factor for Gamma Rays Penetrating Into a Compartmented Structure

In order to correlate some basic measurements of radiation attenuation made on an aircraft carrier to other situations and geometries, experiments were carried out to study the effects of source distance on the dose distribution inside a model-sized compartmented structure intended to simulate the carrier. Data are presented in the form of buildup factors (B[r) as functions of source-to-detector distance for two configurations of the compartmented structure. Buildup factors are also presented as functions of the slant path through the interposing steel plates for the case where the source is considered far from the structure. Comparisons of B[r within our complex structure with single-slab values are also included. In every case, the buildup factor for the compartmented structure was found to be consistently and significantly lower than the single-slab data. The greatest difference in buildup (B[r-1) amounted to 30 percent.

U.S. Government Research Reports