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Browsing by Author "Mooney, Michael, committee member"

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    Development of a liquid argon purity monitoring system
    (Colorado State University. Libraries, 2023) Fogarty, Samuel J., author; Harton, John, advisor; Mooney, Michael, committee member; Menoni, Carmen, committee member
    Liquid argon time-projection chambers (LArTPCs) are used to detect charged particles and measure their properties. Charged particles that pass through the liquid argon (LAr) in a LArTPC ionize and excite argon atoms, producing ionization electrons and prompt scintillation light. The ionization electrons drift through the LAr volume in a uniform electric field and produce a signal at the anode. The scintillation light is used to determine the drift coordinate of an event, which allows for 3D reconstruction of tracks and interactions. Electro-negative impurities lead to the reduction of the ionization electrons and scintillation light. They worsen a detector's ability to perform event reconstruction by reducing the signal-to-noise ratios. A purity monitor is a device that is often used alongside LArTPCs to monitor the LAr purity. It extracts electrons from a photo-cathode via the photoelectric effect and drifts them through LAr to an anode using an electric field. When traversing the purity monitor, some of the electrons will be lost due to impurities along the way. As a result, the drift-electron lifetime, which is related to the LAr impurity concentration, can be determined by measuring the difference in charge between the cathode and anode. This method allows for continuous purity monitoring of the LAr used in a LArTPC. This thesis describes the development and testing of a purity monitoring system that is used in conjunction with a LArTPC at Colorado State University.
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    ICARUS cosmic ray tagger efficiency
    (Colorado State University. Libraries, 2024) Boone, Tyler N., author; Wilson, Robert, advisor; Fairbank, William, committee member; Mooney, Michael, committee member; Brandl, Alexander, committee member
    The ICARUS Cosmic Ray Tagger (CRT) was constructed with the goal to tag cosmogenic muons passing through the ICARUS Time Projection Chamber (TPC). Construction and commissioning of the detector began in Fall 2019 with the Side CRT North wall and continued for several years through the installation of the Top CRT. In this thesis I will summarize my contributions to the CRT system and describe a measurement of the installed CRT detection efficiency using the TPC.
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    Measurement of the differential charged current single pion cross section using muon momentum and muon angle in the pi zero detector of the T2K experiment
    (Colorado State University. Libraries, 2018) Schwehr, Jaclyn, author; Wilson, Robert J., advisor; Berger, Bruce, committee member; Toki, Walter, committee member; Mooney, Michael, committee member; Brandl, Alexander, committee member
    A measurement of the charged current single pion differential cross section in the pi-zero detector of the T2K experiment is presented as a function of reconstructed muon momentum and muon angle. This measurement is done with particular care taken to minimize model dependence throughout the analysis, specifically with careful signal definition and efficiency corrections. New methods for improving the reconstruction of low energy pions are included, as is a method for fitting background events induced by signal physics without introducing model dependence to the fit. Run 4 water-in data is used to make this measurement, which corresponds to an exposure of 1.63×1020 protons on target. The differential cross section measurement is made per nucleon for all targets in the fiducial volume of the pi-zero detector over muon angles of 0◦ to 90◦ with respect to the incident neutrino beam direction, and muon momenta from 150 MeV to 5 GeV. The measured cross sections are lower than those predicted by the default Rein Sehgal resonance and coherent models, favoring the Minoo resonance and Berger Sehgal coherent models.
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    Modeling strontium-90 transport and potential remediation from a contaminated aquifer
    (Colorado State University. Libraries, 2019) Phillips, Preston, author; Borak, Thomas, advisor; Mooney, Michael, committee member; Brandl, Alexander, committee member
    Radioactive waste injected into depleted oil reservoirs runs the risk of contaminating local aquifers if the bore casing of the injection hole were to fail. The currently proposed method of remediation involves multiple iterations of flushing to remove all contaminants. This is inefficient as the radionuclides adsorb into the aquifer rock and desorb back into the water table after a period of time. The adsorption/desorption kinetics for the activity concentration in the injection solution have been transformed into first order rate equations to model the interactions over time. The adsorption of Sr-90 has been modeled as a competitive process between two categories of rock. In parallel, almond hulls have been proposed as potential biosorbents for Sr-90. The kinetics have also been modeled into first order equations. This study quantifies how the addition of the almond hull kinetics will affect the activity concentration in the injection solution and within the two rock types. It simulates how the addition of an almond hull biosorbent into the injection solution would immobilize the radionuclides reducing the activity in the surrounding rock. With the biosorbent added to the system, the activity concentration in the injection solution is 39% of the activity concentration without by the 10th day. It was found that there was an 62% reduction in the total activity concentration in Rock Type 1 and Rock Type 2 after 10 days compared to adsorption using no biosorbent.
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    Precision measurement and symmetry properties of metastable hydrogen
    (Colorado State University. Libraries, 2022) Rasor, Cory M., author; Yost, Dylan, advisor; Roberts, Jacob, committee member; Mooney, Michael, committee member; Bartels, Randy, committee member
    Hydrogen has been an indispensable system to study during the development of quantum mechanics due to the simplicity of its atomic structure. Hydrogen maintains its utility today as an important tool for determining fundamental values such as the Rydberg and fine structure constants, as well as the proton charge radius. The work described in this thesis aims to use hydrogen for determining the proton Zemach radius, to search for anomalous spin-dependent forces, and to provide means for measuring the degree of parity violation within this simple system. An overview of a 2S1/2 hyperfine interval measurement is described, followed by a description of the apparatus used and finally a discussion of the systematic effects to be characterized. A proposed parity violation experiment is also described.
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    Quantification of the directional detection capability of the DRIFT-IIe dark matter search detector via the range of nuclear recoil tracks in two dimensions
    (Colorado State University. Libraries, 2021) Schuckman, Frederick G., II, author; Harton, John, advisor; Toki, Walter, committee member; Mooney, Michael, committee member; Marconi, Mario, committee member
    Evidence suggests that 83% of the matter content of the universe is dark matter. Despite its ubiquity, the identity of this matter is unknown. It is thought that a halo of dark matter surrounds and is distributed throughout our galaxy. The Weakly Interacting Massive Particle (WIMP) has been a popular dark matter candidate. As we move through this halo it should appear as a wind of WIMPs incident upon us. A properly-placed detector could have this wind blow through its top face at one time in the day, and through a side face 12 sidereal hours later. DRIFT-IIe is a low-pressure gas negative-ion time projection chamber designed for direct and directional detection of WIMPs elastically scattering from gas nuclei. Partial directional information of a WIMP recoil could be extracted by measuring the range of the track of ionization that it produces in two dimensions. To study this signature, the detector was exposed to a source of neutrons in a series of runs. In one run the source was placed above the detector and in a second run the source was placed to the side of the detector. Neutron recoils mimic those expected from WIMPs, and the source placement mimics a specific WIMP wind direction. For the two runs, the range information was compared with a Monte Carlo resampling test. It was found on average 302 +/- 4 neutron recoils, sampled with WIMP-like energy spectra, are required along each of these axes to discern the two populations with a significance of 3σ.