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dc.contributor.advisor Baxter, David V. en Lavelle, Christopher M. en 2010-06-01T22:01:45Z en 2027-02-01T23:01:45Z en 2010-06-11T14:07:59Z 2010-06-01T22:01:45Z en 2007 en
dc.identifier.uri en
dc.description Thesis (PhD) - Indiana University, Physics, 2007 en
dc.description.abstract Neutron scattering research is performed primarily at large-scale facilities. However, history has shown that smaller scale neutron scattering facilities can play a useful role in education and innovation while performing valuable materials research. This dissertation details the design and experimental validation of the LENS TMR as an example for a small scale accelerator driven neutron source. LENS achieves competitive long wavelength neutron intensities by employing a novel long pulse mode of operation, where the neutron production target is irradiated on a time scale comparable to the emission time of neutrons from the system. Monte Carlo methods have been employed to develop a design for optimal production of long wavelength neutrons from the 9Be(p,n) reaction at proton energies ranging from 7 to 13 MeV proton energy. The neutron spectrum was experimentally measured using time of flight, where it is found that the impact of the long pulse mode on energy resolution can be eliminated at sub-eV neutron energies if the emission time distribution of neutron from the system is known. The emission time distribution from the TMR system is measured using a time focussed crystal analyzer. Emission time of the fundamental cold neutron mode is found to be consistent with Monte Carlo results. The measured thermal neutron spectrum from the water reflector is found to be in agreement with Monte Carlo predictions if the scattering kernels employed are well established. It was found that the scattering kernels currently employed for cryogenic methane are inadequate for accurate prediction of the cold neutron intensity from the system. The TMR and neutronic modeling have been well characterized and the source design is flexible, such that it is possible for LENS to serve as an effective test bed for future work in neutronic development. Suggestions for improvements to the design that would allow increased neutron flux into the instruments are provided. en
dc.language.iso EN en
dc.publisher [Bloomington, Ind.] : Indiana University en
dc.subject Cold Neutron Moderator en
dc.subject MCNP en
dc.subject Cold Neutron en
dc.subject Neutronics en
dc.subject Neutron Source en
dc.subject Neutron Production en
dc.subject.classification Physics, Radiation en
dc.subject.classification Physics, Condensed Matter en
dc.subject.classification Physics, Nuclear en
dc.title The Neutronic Design and Performance of the Indiana University Cyclotron Facility (IUCF) Low Energy Neutron Source (LENS) en
dc.type Doctoral Dissertation en

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