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dc.contributor.advisor Liu, Chen-Yu en Salvat, Daniel Joseph en 2015-04-19T07:23:08Z 2015-04-19T07:23:08Z 2015-04 en 2015 en
dc.description Thesis (Ph.D.) - Indiana University, Physics, 2015 en
dc.description.abstract Neutron decay is the simplest example of nuclear beta-decay. The mean decay lifetime is a key input for predicting the abundance of light elements in the early universe. A precise measurement of the neutron lifetime, when combined with other neutron decay observables, can test for physics beyond the standard model in a way that is complimentary to, and potentially competitive with, results from high energy collider experiments. Many previous measurements of the neutron lifetime used ultracold neutrons (UCN) confined in material bottles. In a material bottle experiment, UCN are loaded into the apparatus, stored for varying times, and the surviving UCN are emptied and counted. These measurements are in poor agreement with experiments that use neutron beams, and new experiments are needed to resolve the discrepancy and precisely determine the lifetime. Here we present an experiment that uses a bowl-shaped array of NdFeB magnets to confine neutrons without material wall interactions. The trap shape is designed to rapidly remove higher energy UCN that might slowly leak from the top of the trap, and can facilitate new techniques to count surviving UCN within the trap. We review the scientific motivation for a precise measurement of the neutron lifetime, and present the commissioning of the trap. Data are presented using a vanadium activation technique to count UCN within the trap, providing an alternative method to emptying neutrons from the trap and into a counter. Potential systematic effects in the experiment are then discussed and estimated using analytical and numerical techniques. We also investigate solid nitrogen-15 as a source of UCN using neutron time-of-flight spectroscopy. We conclude with a discussion of forthcoming research and development for UCN detection and UCN sources. en
dc.language.iso en en
dc.publisher [Bloomington, Ind.] : Indiana University en
dc.subject magnetic trap en
dc.subject neutron lifetime en
dc.subject neutron scattering en
dc.subject solid nitrogen en
dc.subject ultracold neutrons en
dc.subject vanadium en
dc.subject.classification Physics en
dc.subject.classification Particle physics en
dc.subject.classification Nuclear physics en
dc.title A Magneto-Gravitational Neutron Trap for the Measurement of the Neutron Lifetime en
dc.type Doctoral Dissertation en

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