Donald J. Hughes

Neutron cross sections

Most recent reliable data on several neutron cross sections for a variety of isotopes were collected in tabular and graphic form. The collection is intended as a revised version of BNL-170, and in addition to cross section information, contains tables of resonance parameters. (D.E.B.)

Direct measurement of the energy variation of η for U233, U235, and PU239☆

Abstract A technique is described that measures directly the energy variation of η the number of fission neutrons produced per neutron absorbed. When combined with total cross-sections, the method is capable of giving fission cross-sections as well. Results are presented in the energy region near thermal, of importance to reactor design, for U233, U211, and Pu29. Comparison with η computed from total and fission cross-sections shows good agreement for U233 and U235 but a disagreement outside experimental error for Pu239 An auxiliary experiment demonstrates that v, the number of neutrons per fission, is constant with energy in the region of interest for Pu239 hence that the discrepancy cannot be ascribed to a v variation.

Physics in Poland and Russia

This past summer I spent a very busy month in a manner I hardly would have predicted a few years ago—visiting Polish and Soviet scientists, accompanied by my wife, as a guest of their governments. The trip was unusual in that I was not attending a conference, as has been true for most visits of US physicists, but was lecturing and consulting on an individual basis. The resulting informality meant that I was able to learn about a wide variety of physics research and to talk at length to many individuals. As the Russian visit was preceded by two weeks in Poland, I had a chance to learn much about the Soviet work from within, so to speak. Actually, the freedom of discussion in Poland helped to prepare me, in a valuable way, for uncovering details of developments after I reached Russia.

Nuclear information obtainable from low energy neutron spectroscopy

AbstractThe results of measurements of thermal-neutron cross sections, level distributions in the resonance region,

Direct measurement of the energy variation of ? for U233, U235, and Pu239

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FAST NEUTRON CROSS SECTIONS AND NUCLEAR LEVEL DENSITY

ratios, and determinations of the effective nuclear radius from potential:.scattering of slow neutrons are considered.A discrepancy in the results of measurements of the thermal-neutron fission cross secticn in U235 is noted. The distribution of levels exhibits a deficiency in small spacings as compared with a random distribution, i. e., there seems to be a “repulsion” of levels. The dependence of

MEASUREMENT OF LATTICE VIBRATIONS IN VANADIUM BY NEUTRON SCATTERING

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