Physics Commons^™

Search For The Decays Of 113ba, Yongchi Xiao

Doctoral Dissertations

The search for new alpha-emitters in the region above tin-100 was carried out in Japan Atomic Energy Agency (JAEA) tandem accelerator in Tokai, Japan. This work aimed to discover barium-113 produced via the fusion-evaporation reaction nickel-58(nickel-58,3n)barium-113 and observation through its alpha-decay chain from barium-113 to xenon-109 to tellurium-105 and tin-101. In the proof of principle experiment in March 2014, the alpha-decay chain of xenon-109 was observed with Double-sided Silicon Strip Detector (DSSD) and digital electronics at JAEA Recoil Mass Separator (RMS). The first discovery-oriented barium-113 experiment was carried out in December 2014 searching for its alpha-decay, ground-state to ground-state beta-decay …

Total Absorption Spectroscopy Of Neutron Rich Nuclei Across The N=50 Neutron Shell Closure, Kathleen Conner Goetz

Doctoral Dissertations

Decay spectroscopy of neutron rich nuclei near doubly magic 78^Ni [78-Nickel] is relevant to nuclear structure and astrophysics as well as reactor and neutrino physics. β-decay [beta-decay] calorimetry studies are essential to reconstruct the decay strength function and is used to overcome the problems arising from the high density of states leading to nuclear Pandemonium. The Modular Total Absorption Spectrometer, currently located in HRIBF at the Oak Ridge National Laboratory, collected data on 25 fission products of ²³⁸U [238-Uranium] during a run in March 2015. Analysis of the ^84,85,86Br [84, 85 and 86-Bromine] data from the …

Measurement Of Heavy Flavor Yield And Azimuthal Anisotropy At Forward Angles In Cu + Au Collisions At A Center-Of-Mass Collision Energy Per Nucleon Of 200 Gev, Brandon Kyle Schmoll

Doctoral Dissertations

Heavy flavor quarks are produced early in heavy ion collisions and will experience the full evolution of the Quark Gluon Plasma (QGP). Measurements at forward rapidity may be influenced as much, or more, by the cold nuclear matter effects as by the hot nuclear matter effects associated with a QGP. As the medium evolves, the initial spatial anisotropy of participants is converted to an azimuthal anisotropy in the momentum space of outgoing particles. Therefore, the momentum spectra modification and anisotropy parameters provide useful information about the heavy quark interaction with the bulk medium.

Asymmetric heavy ion collisions, such as Cu+Au, …

Remote Neutron Spectroscopy On Mars, Christopher Gayle Tate

Doctoral Dissertations

Remote neutron spectroscopy is an important technique in planetary science that allows for classification of the amount of light elements in a planetary regolith. It is especially suited for studying hydrogen abundances and elements with high thermal neutron absorption cross sections in the top ~1 meter of regolith. The Mars Science Laboratory rover Curiosity carries the first rover based neutron spectrometer Dynamic Albedo of Neutrons (DAN) in Gale crater, Mars. As the DAN instrument operates in passive mode, it is sensitive to neutrons produced through Galactic Cosmic Ray interactions and neutrons generated by the rover's Multi-Mission Radioisotope Thermoelectric Generator. In …

Jet-Hadron Correlations Relative To The Event Plane Pb--Pb Collisions At The Lhc In Alice, Joel Anthony Mazer

Doctoral Dissertations

In relativistic heavy ion collisions at the Large Hadron Collider (LHC), a hot, dense and strongly interacting medium known as the Quark Gluon Plasma (QGP) is produced. Quarks and gluons from incoming nuclei collide to produce partons at high momenta early in the collisions. By fragmenting into collimated sprays of hadrons, these partons form 'jets'. Within the framework of perturbative Quantum Chromodynamics (pQCD), jet production is well understood in pp collisions. We can use jets measured in pp interactions as a baseline reference for comparing to heavy ion collision systems to detect and study jet quenching. The jet quenching mechanism …

Production Of Electrons From Heavy Flavor Decays In Proton-Lead Collisions Measured With Alice At The Lhc, Rebecca Michelle Scott

Doctoral Dissertations

This dissertation presents a measurement of the yield and cross section of electrons from heavy flavor decays at central rapidity in proton-lead collisions measured by the ALICE (A Large Ion Collider Experiment) detector at the Large Hadron Collider. This analysis extends the transverse momentum reach of an earlier measurement in ALICE and the comparison is shown. The cross section of single electrons in proton-lead collisions is compared to the value expected in the absence of nuclear modification from proton-proton collisions. The cross section is well described by the perturbative Quantum Chromodynamics and no statistically significant alteration due to hot nuclear …

Improving Predictive Capabilities Of Classical Cascade Theory For Nonproliferation Analysis, David Allen Vermillion

Doctoral Dissertations

Uranium enrichment finds a direct and indispensable function in both peaceful and nonpeaceful nuclear applications. Today, over 99% of enriched uranium is produced by gas centrifuge technology. With the international dissemination of the Zippe archetypal design in 1960 followed by the widespread illicit centrifuge trafficking efforts of the A.Q. Khan network, traditional barriers to enrichment technologies are no longer as effective as they once were. Consequently, gas centrifuge technology is now regarded as a high-priority nuclear proliferation threat, and the international nonproliferation community seeks new avenues to effectively and efficiently respond to this emergent threat.

Effective response first requires an …

A Search For Double Beta Decay Of Xenon To Excited States Of Barium With Exo-200, Sereres Johnston

Doctoral Dissertations

This thesis presents searches for several modes of double beta decays of 136Xe to two low-lying excited levels of 136Ba. For each final level, both 2ν and 0ν double beta decay processes are considered. The data and general techniques developed by the EXO-200 collaboration are used, including a Machine Learning process to improve sensitivity in multivariate space. EXO-200 is an experimental program searching for 0νββ decay in a time projection chamber filled with 175 kg of liquid Xenon enriched to 80% 136Xe, functioning as both source and detector. Experimental searches of double beta decay with 136Xe and other isotopes are …