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

$a\approx (bc)^{2}f$

A numerical coefficient would then be included to create the Bethe–Feynman formula—increasing accuracy by more than an order of magnitude.^[3]

$E_{f}f=\left({\frac {E_{2}}{\gamma -1}}\right)\cdot \alpha _{max}^{2}\cdot R_{crit}^{2}\cdot \left({\frac {\delta }{1-\delta }}\right)\cdot \left({\frac {2+3\delta }{2}}\right)$

where γ is the thermodynamic exponent of a photon gas, $E 2$ 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 $(R core - R crit) / R crit$ .

References

^ "4.1 Elements of Fission Weapon Design".
^ 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.

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[1] "4.1 Elements of Fission Weapon Design".

[2] 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.

[Atmospheric_electrodynamics-3] Hans Volland (1995). Handbook of atmospheric electrodynamics, Volume 2. CRC Press. ISBN 0-8493-2520-X.

[1]

[2]

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v t e Richard Feynman
Career	Feynman diagram Feynman–Kac formula Wheeler–Feynman absorber theory Bethe–Feynman formula Hellmann–Feynman theorem Feynman slash notation Feynman parametrization Path integral formulation Parton model Sticky bead argument One-electron universe Quantum cellular automaton Rogers Commission Report Feynman checkerboard Feynman sprinkler
Works	"There's Plenty of Room at the Bottom" (1959) The Feynman Lectures on Physics (1964) The Character of Physical Law (1965) QED: The Strange Theory of Light and Matter (1985) Surely You're Joking, Mr. Feynman! (1985) What Do You Care What Other People Think? (1988) Feynman's Lost Lecture: The Motion of Planets Around the Sun (1997) The Meaning of It All (1999) The Pleasure of Finding Things Out (1999) Perfectly Reasonable Deviations from the Beaten Track (2005)
Family	Joan Feynman (sister) Charles Hirshberg (nephew)
Related	Namesakes Cargo cult science Quantum Man: Richard Feynman's Life in Science Tuva or Bust! Feynman Prize in Nanotechnology Infinity (1996 film) QED (2001 play) The Challenger Disaster (2013 film)

Related formula

See also

References