Abstract
This chapter forms the heart of this book. After deriving the properties of neutron travel through materials, a detailed analysis is presented of how the critical mass of a fissile material, in both “bare” and “tampered” configurations, can be calculated. The calculations are applied to both uranium-235 and plutonium-239. Analytic expressions are developed for estimating bomb energy yield and efficiency. A numerical simulation is developed to analyze conditions of pressure, fission rate, expansion, and energy yield within a fissioning bomb core, and is applied to the Hiroshima Little Boy bomb. Spreadsheets for performing the calculations are made available to interested users through a supporting website.
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All Excel sheets are available at http://www.manhattanphysics.com
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© 2011 Springer-Verlag Berlin Heidelberg
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Reed, B.C. (2011). Critical Mass and Efficiency. In: The Physics of the Manhattan Project. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-14709-8_2
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DOI: https://doi.org/10.1007/978-3-642-14709-8_2
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