No description available.

No description available.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1971. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

The associated particle technique was employed to produce a collimated beam of 4.3 MeV neutrons from the reaction D(d,n)3He. A rotating target assembly permitted the use of thin deuterated polyethylene deuterium targets. The use of a position sensitive detector in the associated particle technique was demonstrated. Data was accumulated by an on-line computer system. The differential scattering cross section for 4.3 MeV neutrons was measured for scattering samples of uranium, bismuth, and lead over the angular range of 5° to 15°. The data were corrected for the effects of finite angular resolution, neutron multiple scattering, air scattering, and neutron inelortic scattering. The experimental scattering cross sections were in agreement with those calculated on the basis of a nuclear optical model interaction plus an electromagnetic Schwinger interaction. No evidence was found to substantiate anamalous cross sections at small angles. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

No description available.

No description available.

Measurements of the angular distribution and total reaction rate in neutron-proton scattering are described. The emphasis of this work has been to obtain an accurate normalization of the distribution, which is difficult to achieve with neutral beams. Nearly monoenergetic neutrons from the d(p,n)pp reaction were scattered from a liquid hydrogen target. The neutron beam energy was determined from the time of flight with respect to the radio frequency signal of the TRIUMF cyclotron. The differential cross section was measured at 319 and 493 MeV from 10 to 180 degrees in the centre of mass (CM.). Calibrated neutron beam monitors upstream of the scattering target provided an absolute normalization over the whole angular range. Between 10 and 100 degrees CM. a neutron detector consisting of a charged particle veto, a carbon convertor and two trigger scintillators sandwiching 7 multiwire proportional chambers was used to select elastic neutrons by time of flight techniques. The neutron angular distribution was measured with an average precision of 5% and an uncertainty on the normalization of 1.3%. An associated particle experiment (neutrons and recoil protons detected in coincidence) determined the efficiency of the neutron detector and the monitors were calibrated by measuring the incident neutron flux with the neutron detector in the beam, i.e. at zero degrees. The recoil protons were detected in the angular range between 60 and 180 degrees CM. with a precision of 1% to 2% and an error on the normalization of 2.8% at 319 MeV and 3.7% at 493 MeV. Elastic events were selected by time of flight and by either a measurement of magnetic rigidity (momentum) or total energy. The absolute normalization of the two experimental techniques is verified by the overlap of the two measurements and by comparing the integrated differential cross section with the measured total cross section. The neutron-proton total cross section was measured at six energies between 200 and 500 MeV by a transmission type experiment to a precision of 1% to 3%. The systematic corrections were small, of the order of 1%, and the statistical errors were increased to include monitor and beam instabilities. The measurements show a smooth quadratic energy dependence. The data was included in a phase shift analysis and a dispersion relation analysis along with the previous world data. Agreement between the real part of the forward scattering amplitude predicted by the phase shift analysis and by the dispersion relation analysis is improved. The errors on the 1=0 (isoscalar) phase shifts are decreased and to a lesser extent on the 1=1 phase shifts. There is a marked improvement in the smooth variation with energy of the 1=0 phase shifts and a better agreement of the higher partial waves with the theoretical predictions of the Paris potential. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Thesis. 1977. Ph.D.--Massachusetts Institute of Technology. Dept. of Nuclear Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Bibliography : leaves 226-229. / Ph.D.

<p> A new technique has be~n developed for the measurement of fast neutron total cross-sections in the range 0.8 -> 3.0 MeV using the fast neutrons from a reactor. The method was used to obtain the cross-section of six elements in the 2s-1d shell. Various analytical techniques have been applied to measure the behavior of the average cross-sections and delineate the properties of the observed resonances. From these results the resonances are confirmed as examples of "doorway" states, and conclusions are drawn about the distributions of the parameters of these states. The average properties are related to nuclear models of the origin and characteristics of states of high excitation in the target nuclides.</p> / Thesis / Doctor of Philosophy (PhD)