A PRELIMINARY INVESTIGATION OF 'IN-AND-DOWN' AND 'IN-AND-UP' RADIATION COMPONENTS
CONESCO WATERTOWN MA
Pagination or Media Count:
An experiment was designed to measure the attenuation afforded by horizontal barriers both above and below ground to radiation that originated from sources lying on the ground surrounding a structure. Measured attenuation factors in the downward direction in-and-down agreed fairly well with calculated factors for the two barrier-mass thicknesses 486. and 97.2 psf investigated. The observed dose rates in the basement of the ceilingless structure agreed fairly well with the existing theory, while large discrepancies between theory and experiment were found in the experiment dealing with the structure basement which had a ceiling. This discrepancy increased with decreasing solid-angle fraction with the theory underestimating the dose rate in the basement by as much as a factor of 3. The experimental results were consistent with past experiments conducted in basement structures in their comparison with theory. A modification to the theory in which a new barrier factor was calculated as a function of the barrier thickness and average solid- angle fraction subtended at the detector by the first-floor external wall agrees quite well with this experiment and past experimental results. The calculated attenuation factors in the upward direction in-and-up radiation component underestimated the experimental results for large or infinite fields of contamination, and over-estimated the attenuation afforded by the floor from contamination within 50 feet of the structure walls.
- Structural Engineering and Building Technology
- Radioactivity, Radioactive Wastes and Fission Products