Physical Sciences and Mathematics Commons^™

An Analysis Of The Parity Violating Asymmetry Of Polarized Neutron Capture In Hydrogen From The Npdgamma Experiment, Elise Tang

Theses and Dissertations--Physics and Astronomy

The NPDGamma Experiment is used to study the n + p to d + g reaction for the purpose of examining the hadronic weak interaction. The nucleon-nucleon interaction is overwhelmingly mediated by the strong force, however, the weak part can be extracted by a study of its parity violating manifestations. When neutrons are incident on protons, deuterons and 2.2 MeV gamma rays are produced. If the incoming neutrons are polarized, the parity violating weak interaction gives rise to a measured spatial asymmetry, A_g, in the outgoing gamma rays, as s_n · k_g is parity odd.

At …

The N-P Scattering Cross Section From 90 Kev To 1.8 Mev, Hongwei Yang

Theses and Dissertations--Physics and Astronomy

There have been very few measurements of the total cross section for n-p scattering below 500 keV. In order to differentiate among NN potential models, improved cross section data between 20 and 600 keV are required. We measured the n-p and n-C total cross sections in this energy region by transmission; a collimated neutron beam was passed through CH₂ and C samples and transmitted neutrons were detected by a BC-501A deuterated liquid scintillator. Cross sections were obtained by taking the ratios of normalized neutron yields with the samples in the beam and with no sample in the beam. Both …

A Measurement Of The Prompt Fission Neutron Energy Spectrum For 235U(N,F) And The Neutron-Induced Fission Cross Section For 238U(N,F), Zachariah W. Miller

Theses and Dissertations--Physics and Astronomy

Two measurements have been made, addressing gaps in knowledge for ²³⁵U(n,f) and ²³⁸U(n,f). The energy distribution for prompt fission neutrons is not well-understood below 1 MeV in ²³⁵U(n,f). To measure the ²³⁵U(n,f) prompt fission neutron distribution, a pulsed neutron beam at the WNR facility in Los Alamos National Laboratory was directed onto a ²³⁵U target with neutron detectors placed 1 m from the target. These neutron detectors were designed specifically for this experiment and employed a unique geometry of scintillating plastic material that was designed to reject backgrounds. Fission fragments were detected using an avalanche …

Measurement Of The Dμd Quartet-To-Doublet Molecular Formation Rate Ratio (Λq : Λd) And The Μd Hyperfine Rate (Λqd) Using The Fusion Neutrons From Μ− Stops In D2 Gas, Nandita Raha

Theses and Dissertations--Physics and Astronomy

The MuSun experiment will determine the μd capture rate (μ−+d ->n+n+ν_e) from the doublet hyperfine state Λ_d, of the muonic deuterium atom in the 1S ground state to a precision of 1.5%. Modern effective field theories (EFT) predict that an accurate measurement of Λ_d would determine the two-nucleon weak axial current. This will help in understanding all weak nuclear interactions such as the stellar thermonuclear proton-proton fusion reactions, the neutrino reaction ν+d (which explores the solar neutrino oscillation problem). It will also help us understand weak …

Search For A Permanent Electric Dipole Moment Of 225Ra, Mukut R. Kalita

Theses and Dissertations--Physics and Astronomy

The observation of a permanent electric dipole moment (EDM) in a non-degenerate system would indicate the violation of discrete symmetries of Time reversal (T) or combined application of Charge (C) and Parity (P) symmetry violation through the CPT theorem. The diamagnetic ²²⁵Ra atom with nuclear spin I=1/2 is a favorable candidate for an EDM search. Experimental sensitivity to its EDM is enhanced due to its high atomic mass and the increased Schiff moment of its octupole deformed nucleus. An experimental setup is developed where laser cooled neutral radium atoms are collected in a …