Photofission and Photoneutron Emission in Uranium

Duffield, R.B.; Huizenga, J.R.

doi:10.1103/physrev.89.1042

Cited by 30 publications

(6 citation statements)

References 17 publications

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“…Fission in IP 38 The observed photofission yield curves (Fig. 2) may be interpreted as the superposition of two components, a low-energy asymmetric (double-humped) curve and a high-energy single-humped curve, produced by the absorption of high-energy photons.…”

Section: B Quantitative Interpretation Of X-raymentioning

confidence: 99%

“…These data are given in column 2 of Table V where the energy intervals are given in column 1. The measured cross section 38 for the resonance absorption can be used to calculate the average cross section for high-energy fission for the various energy intervals. These values are given in column 3 of Table V, where it is seen that the cross section is roughly constant for photon energies above 16 Mev, with a value of about 7 millibarns.…”

Section: Average Cross Section For Symmetric Fission For Various Xmentioning

confidence: 99%

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Uranium Photofission Yields

Schmitt

Sugarman

1954

Phys. Rev.

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The photofission yield-mass curve of natural uranium for 48-Mev x-rays was determined radiochemically. Isolation of selected peak and trough fission products at various maximum x-ray energies, 7 Mev, 10 Mev, 16 Mev, 21 Mev, 48 Mev, 100 Mev, and 300 Mev showed that the peak-to-trough ratio decreased from 300 to 4 as the maximum x-ray energy increased from 7 Mev to 300 Mev. The observed photofission yield curves may be quantitatively interpreted as the superposition of two components, a low-energy asymmetric (doublehumped) curve and a high-energy single-humped curve. The average cross section for symmetric fission for photons in the energy range 16 Mev to 300 Mev is about 7 millibarns. I. INTRODUCTIONM ANY investigations of high-energy fission, induced by particles and x-rays, have been reported. 1-12 One striking feature of these studies is the decrease in the peak-to-trough yield ratio of the yieldmass curve as the energy of the bombarding particle increases, resulting in the one hump yield-mass curve as the energy of the particle enters the hundred-Mev range. A systematic investigation of the photofission of a heavy nuclide at various energies has not been reported.The purpose of this work was essentially threefold; (1) to determine the yield-mass curve of natural uranium for 48-Mev maximum x-rays by the comparison method; 4,13,14 (2) to study the changes in the photoyield curve of uranium as a function of increasing maximum x-ray energy from 7 Mev to 300 Mev; and (3) to study the change in the neutron-to-proton ratio of primary fission fragments with increasing x-ray energy. On the assumption that the observed fission-yield curves are composites of two idealized curves, 14 one *

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Section: B Quantitative Interpretation Of X-raymentioning

confidence: 99%

Section: Average Cross Section For Symmetric Fission For Various Xmentioning

confidence: 99%

Uranium Photofission Yields

Schmitt

Sugarman

1954

Phys. Rev.

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“…Corrections of 20 percent are made for multiple neutron emission for Ta, 16 Pb (assumed the same as Ta); and corrections of 35 percent for fission and emission of two neutrons by U. 17 Corrections for multiple particle emission are believed small in this energy region for the other nuclei.…”

Section: Bremsstrahlung-weighted Cross Sectionmentioning

confidence: 99%

“…3, and given in Eqs. (16), (17), (18) for a calculation with simple harmonic oscillator (SHO) independent-particle model for He 4 , O 16 , and Ca 40 respectively. The LB calculation (reference 2) for a Fermi gas model is given in Eq.…”

Section: Exchange Force Contribution To Integrated Cross Sectionmentioning

confidence: 99%

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Independent-Particle Model and the Nuclear Photoeffect. II

Levinger

1955

Phys. Rev.

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A simple harmonic oscillator independent-particle model is used for sum-rule calculation of electric dipole transitions in the nuclear photoeffect. First we find the level spacing hco = 4:2A~i Mev for nuclear radius parameter ro=1.2. Combining this result with the integrated cross section, we find the bremsstrahlungweighted cross section cb~f( is not inconsistent with a preliminary analysis of experimental measurements for He, Be, C, Al, Cu, Mo, Ag, Ta, Pb, and U. We also use the simple harmonic oscillator independent-particle model to calculate the increase in the integrated cross section due to neutron-proton exchange forces. We find that the relative increase is not far from the Levinger-Bethe value of 0.8x (where x is the fraction of exchange force) for the closed-shell nuclei He 4 , O 16 , and Ca 40 , for both Gaussian and Yukawa neutron-proton potentials, and for two values of the radius parameter ro: 1.2 or 1.5.

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Sonstige Verwendung

Taumann¹

1980

U Uran

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Photofission and Photoneutron Emission in Uranium

Cited by 30 publications

References 17 publications

Uranium Photofission Yields

Uranium Photofission Yields

Independent-Particle Model and the Nuclear Photoeffect. II

Sonstige Verwendung

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