• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 371
  • 345
  • 50
  • 46
  • 46
  • 46
  • 46
  • 46
  • 46
  • 17
  • 2
  • 1
  • Tagged with
  • 996
  • 996
  • 359
  • 345
  • 178
  • 140
  • 137
  • 120
  • 110
  • 80
  • 80
  • 79
  • 74
  • 60
  • 54
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

An investigation of the level structure of nitrogen-14 by the bombardment of carbon-13 with protons

Belote, Thomas A. January 1962 (has links)
States in N14 in the region of excitation energy between 10.6 and 12.2 Mev have been studied by means of the C 13(p,n)N13, C13(p,d)C12, and C13(p,p1)C13* reactions. The C13(p,n)N13 total cross section has been measured from threshold, Eplab = 3.236, to 5.2 Mev in 30-kev steps by measuring the activation of the N13(half life = 10.1 min). The differential cross sections for the C13(p,d)C 12 and C13(p,p1)C13* reactions have been taken at center of mass angles near thetacm = 90° and 160°. This data along with that of Kashy et al., of the elastically scattered protons from C13 have been analyzed. Reaction-particle widths for the 11.05 (1+), 11.240 (3 -), 11.30 (2-), 11.39 (1+), and 11.503 (3+) states assigned from the elastic scattering data have been determined. Resonances at Eplab = 4.50 Mev (Gamma = 140 kev) 4.58 (Gamma = 60), 4.76 (Gamma = 320) and 5.04 (Gamma = 320) corresponding to levels at 11.72, 11.80, 11.96 and 12.22 Mev with assignments of 1-, 2+, 2 -, and 3- have also been investigated. Reaction particle-widths for these states have also been determined.
172

Pair spectrograph measurements of the radiations from the deuteron bombardment of boron-10, carbon-12, and fluorine-19 and the proton bombardment of boron-11 and fluorine-19

Bent, Robert D. January 1954 (has links)
The importance of studying the radiations emitted by nuclei can be understood by considering the kind of information that can be obtained from such a study. Much information can be obtained with a pair spectrograph. The pair process is particularly suited for studying high energy (>3 Mev) transitions since pair production is increasingly probable at higher energies, and since this method makes possible the resolution of complicated spectra. The magnetic lens spectrometer is suited for pair measurements because of its large efficiency for transmitting pairs relative to most other types of spectrometers. Previous measurements have been made with magnetic lens pair spectrometers by Bame and Baggett (Ba 51a) and by D. E. Alburger (Al 52). The purpose of this work was to use a magnetic lens pair spectrograph of improved design to study the pair spectra from some light nuclear reactions. This paper describes a number of experiments which were performed to investigate the pair spectra resulting from the deuteron bombardment of B 10, C12, and F19, and the proton bombardment of B11 and F19. The apparatus and experimental techniques are described, and the results of the experiments are presented.
173

The magnetic moment of free electrons

Besdin, David Jacob January 1950 (has links)
It is generally believed that many of the properties of solid bodies could be determined theoretically to very good approximation if it were possible to solve completely the Schrodinger wave equation for the motion of an electron in a solid. It is presupposed that the forces in solids are known, and that the effect of the lattice and other electrons on the motion of a single electron can be included in some periodic potential function having the periodicity of the lattice. Usually, this potential function is unknown, but the fact that it has the periodicity of the lattice is sufficient to determine many of the characteristic properties of the solid. We know that the wave function for the motion of an electron through the lattice is that of an infinite plane wave with a function having the lattice periodicity as amplitude, and that the corresponding energies are distributed in bands or zones, the structure of which is determined for each lattice by its particular periodicity.
174

Two nucleon stripping reactions and the role of the tensor force

Bilhorn, David E. January 1962 (has links)
In recent years an increasing number of nuclear reactions have been studied experimentally in which more then one nucleon is transferred from the bombarding particle to the target nucleus. The reactions studied are primarily those in which two nucleons are transferred from an incident three or four nucleon complex, for example (He3,p), (alpha,d), etc. The structure of the angular distributions seem to indicate that at high enough energies "direct" reaction mechanisms may be the predominant reaction process. In section I and II we formulate a plane wave Born Approximation direct reaction treatment of the general stripping reaction based on the work of W. Tobocman. Section III is devoted to reviewing the deuteron induced reactions using this formalism to make clear why tensor force and finite range effects are small in these reactions. The formalism is applied to the two nucleon stripping reaction, specifically the (He3,p) reaction in Chapter IV. To investigate the importance of tensor forces we need to know the properties of the 3-nucleon ground state wave function and of the residual nucleus wave function. A discussion of the 3-nucleon ground state is given in Chapter V and Appendix I. A simple L-S coupling shell model for the residual nucleus is used to give explicit expressions for the cross section in Chapter VI. Finally a discussion of the importance of the tensor force and the ramifications of our formalism are given in Chapter VII, for the reaction He4(He 3,p)Li6.
175

Collisions of neutrons with atomic nuclei

Bonner, Tom Wilkerson January 1934 (has links)
The velocity variation of the target areas of nuclei for neutrons has been investigated for neutrons obtained by bombardment of Be, B, and F with Po-alpha-particles. The target area of hydrogen was found to increase rapidly with a decrease in the velocity of the neutrons. The target area of carbon and nitrogen also increased with a decrease in the velocity of the neutrons, but not so rapidly as did that of hydrogen. The absorption of neutrons by lead was found to increase with the velocity. This anomalous absorption of lead can be explained by assuming that faster neutrons make relatively more inelastic collisions with the nuclei. Cosmic-ray bursts can be explained on the basis of this assumption. The neutrons from fluorine were found to be slower than those from boron, and the average range of the recoil protons produced by them was estimated to be about 2 cm in air. These slower neutrons were found to be more penetrating in lead than those from either beryllium or boron.
176

Neutron evaporation spectra from (p,n) reactions

Bramblett, Richard Lee January 1960 (has links)
Abstract Not Available.
177

The interaction of nuclear spins with crystalline lattice vibrations

Briscoe, Charles Victor January 1958 (has links)
Abstract Not Available.
178

A study of the nuclear reactions: c45(p,n)Ti45, Cu63(p,n)Zn63, Cu65(p,n)Zn65, Zn(p,n)Ga, and N14(d,n)O15

Brugger, Robert M. January 1955 (has links)
Abstract Not Available.
179

I. Excitation curves and angular distributions of neutrons from the deuteron bombardment of the boron isotopes. II. Angular correlation of the protons and gamma rays form the deuteron bombardment of lithium six

Burke, William Henry January 1951 (has links)
Abstract Not Available.
180

Neutron thresholds from the reactions T3(pn)He3, Li7(pn)Be7, Be9(dn)B10*, and O16(dn)F17

Butler, James Wilford January 1951 (has links)
Abstract Not Available.

Page generated in 0.0277 seconds