Physics:Bethe–Feynman formula
The Bethe–Feynman efficiency formula, a simple method for calculating the yield of a fission bomb,[1] was first derived in 1943 after development in 1942. Aspects of the formula are speculated to be secret restricted data.[2]
Related formula
- a = internal energy per gram
- b = growth rate
- c = sphere radius
[math]\displaystyle{ a \approx (bc)^2 f }[/math]
A numerical coefficient would then be included to create the Bethe–Feynman formula—increasing accuracy by more than an order of magnitude.[3]
[math]\displaystyle{ E_ff = \left( \frac{1}{\gamma-1} \cdot E_2 \right) \cdot \alpha_{max}^2 \cdot R_{crit}^2 \frac{\delta*(1 + 3*\delta/2)}{(1-\delta)} }[/math]
where γ is the thermodynamic exponent of a photon gas, E2 is the prompt energy density of the fuel, α is V_n (neutron velocity) / λ_mfp_tot (Total reaction mean free path), R_crit is the critical radius and 𝛿 is the excess supercritical radius (Rcore - Rcrit) / Rcrit.
See also
References
- ↑ "4.1 Elements of Fission Weapon Design". http://nuclearweaponarchive.org/Nwfaq/Nfaq4-1.html.
- ↑ Meeting and working with Richard Feynman at Los Alamos, Web of Stories, story by Hans Bethe recorded in December 1996, last accessed 2015/04/20.
- ↑ Hans Volland (1995). Handbook of atmospheric electrodynamics, Volume 2. CRC Press. ISBN 0-8493-2520-X.
 |  |
