Bethe–Feynman formula
The Bethe–Feynman efficiency formula, a simple method for calculating the yield of a fission bomb, was first derived in 1943 after development in 1942. Aspects of the formula are speculated to be secret restricted data.
Related formula
- a = internal energy per gram
- b = growth rate
- c = sphere radius
where γ is the thermodynamic exponent of a photon gas, is the prompt energy density of the fuel, α is V / λ, R is the critical radius and ? is the excess supercritical radius.