Browsing by Author "Wilson, Robert, committee member"
Now showing 1 - 10 of 10
Results Per Page
Sort Options
Item Open Access A study of simulated neutrons in the NOνA near detector(Colorado State University. Libraries, 2020) Jarosz, Jessica, author; Buchanan, Norm, advisor; Wilson, Robert, committee member; Eilertson, Kirsten, committee memberThis thesis explores how neutron interactions can be studied in the NOνA near detector, and the potential use of a deuterium-tritium neutron source. Understanding neutron kinematics within the near detector could aid in constraining antineutrino properties in charged-current quasi-elastic interactions. Refining our knowledge of such an interaction decreases systematic uncertainties, which is crucial for precise neutrino oscillation measurements. Monte-Carlo simulations of mono- energetic neutrons were performed to examine energy deposition, scattering, and neutron energy loss mechanisms.Item Open Access Barium extraction from liquid xenon on a cryoprobe for the nEXO experiment and a nucleon decay search using EXO-200 data(Colorado State University. Libraries, 2019) Craycraft, Adam B., author; Fairbank, William M., Jr., advisor; Roberts, Jacob, committee member; Wilson, Robert, committee member; Johnson, Thomas E., committee memberNeutrinoless double beta decay (0νββ) is a theorized decay that is beyond the standard model of particle physics. Observation of this decay would establish the Majorana nature of neutrinos and show violation of lepton number. Nucleon decay is another theorized decay that is beyond the standard model of particle physics that would violate baryon number. Observation of baryon number violation has been pursued for sometime in a wide variety of experiments. EXO-200 is an experiment that utilized a time projection chamber (TPC) filled with liquid xenon (LXe) enriched in the isotope xenon-136 to search for 0νββ. In this thesis, an analysis of EXO-200 data in search of evidence for triple-nucleon decays in ¹³⁶Xe is presented. Decay of ¹³⁶Xe to ¹³³Sb and decay to ¹³³Te were the particular decays searched for in this analysis. No evidence for either decay was found. Limits on the lifetimes of these decays were set that exceed all prior limits. The proposed nEXO experiment will be next generation LXe TPC search for 0νββ. In order to eliminate background events that are not associated with two neutrino double beta decay, a technique to tag the barium-136 decay daughter is under development. In this thesis, continued development is presented of a scheme to freeze the barium daughter in a solid xenon sample on the end of a cryoprobe dipped into LXe and subsequently tag it using its fluorescence in the solid matrix.Item Open Access Imaging single barium atoms in solid xenon for barium tagging in the nEXO neutrinoless double beta decay experiment(Colorado State University. Libraries, 2016) Walton, Timothy, author; Fairbank, William M., advisor; Berger, Bruce, committee member; Van Orden, Alan, committee member; Wilson, Robert, committee memberThe nEXO experiment will search for neutrinoless double beta decay of the isotope 136Xe in a ton-scale liquid xenon time projection chamber, in order to probe the Majorana nature of neutrinos. Detecting the daughter 136Ba of double beta decay events, called barium tagging, is a technique under investigation which would provide a veto for a background-free measurement. This would involve detecting a single barium ion from within a macroscopic volume of liquid xenon. One proposed barium tagging method is to trap the barium ion in solid xenon at the end of a cold probe, and then detect it by its fluorescence in the solid xenon. In this thesis, new studies on the spectroscopy of deposits of Ba and Ba+ in solid xenon are presented. Imaging of barium atoms in solid xenon is demonstrated with sensitivity down to the single atom level. Achievement of this level of sensitivity is a major step toward barium tagging by this method.Item Open Access Independent measurement of the T2K near detector constraint using the off-axis pi-zero detector(Colorado State University. Libraries, 2019) Hogan, Matthew Gregory, author; Toki, Walter, advisor; Wilson, Robert, committee member; Buchanan, Norman, committee member; Zhou, Wen, committee memberThe Tokai to Kamioka (T2K) experiment is a long-baseline neutrino oscillation experiment hosted in Japan searching for electron neutrino appearance in a high purity muon neutrino beam. In order to constrain the systematic uncertainties in the oscillation analysis, a dedicated near detector (ND) complex called ND280 is located 280 meters from the neutrino production source in line of the beam. To date, the Fine Grain Detector (FGD) in ND280 has provided the ND constraint using a binned maximum likelihood estimate fit. This thesis describes the effort to validate the ND constraint using the same framework, but with an independent data set from the ND280 pi-zero detector (PØD). Expanding on previously developed PØD selections, new selections have been developed to select neutrino and antineutrino events in one and multiple track topologies on water and carbon. These selections are shown to have similar sensitivity to the T2K flux and cross section systematic uncertainties. Using the same parameterization as the official ND constraint result, a hypothesis test was conducted between the PØD-only and FGD-only data fit results. A p-value of 0.2865 was obtained indicating the two data sets are likely describing the same population of neutrinos and their interactions in T2K.Item Open Access Macroscopic manifestations(Colorado State University. Libraries, 2015) Isaiah, Benjamin Hamilton, author; Bates, Haley, advisor; Voss, Gary, committee member; DiCesare, Catherine, committee member; Wilson, Robert, committee memberFrom the latter half of the twentieth century through the present, scientific experimentation, investigation, and observations allow our species to attain a level of unprecedented understanding of the physical world. Our tools are capable of perceptions more advanced than ever before in human history. Technological advancements make visible that which we have never before been able to witness or comprehend, from the smallest transformation of scale and the subatomic particles composing all things in our physical environment, to the greatest galactic super-clusters that we inhabit. Forms in our Universe are determined by natural physical laws and reactions set into motion far into the past, proceeding from the Big Bang. Events occurring at scales humans perceive to be hyper-microscopic ultimately determine the outcome of realities at our existence as seen through the human observational reference frame. In turn, events occurring at scales exponentially larger than the human scale also govern the realities existing at scales beyond our familiar frame of reference, realms that the Euclidian mind can only perceive as the abyss. Macroscopic Manifestations captures moments and events occurring at transformations of scale both massive and miniscule, frozen in time. This sculptural work forms associations between objects occurring at unfamiliar scales of existence and objects occurring at the familiar human scale of existence. Demonstrating the resemblance innate to objects at every scale of existence, much of the work contained herein is representative of microcosmic and macrocosmic phenomena, and emulates structures apparent in terrestrial marvels, the flora and fauna of Earth.Item Open Access Matter effects on neutrino oscillations(Colorado State University. Libraries, 2013) Gordon, Michael, author; Toki, Walter, advisor; Wilson, Robert, committee member; Estep, Donald, committee memberAn introduction to neutrino oscillations in vacuum is presented, followed by a survey of various techniques for obtaining either exact or approximate expressions for νμ→ νe oscillations in matter. The method developed by Arafune, Koike, and Sato uses a perturbative analysis to find an approximation for the evolution operator. The method used by Freund yields an approximate oscillation probability by diagonalizing the Hamiltonian, finding the eigenvalues and eigenvectors, and then using those to find modified mixing angles with the matter effect taken into account. The method devised by Mann, Kafka, Schneps, and Altinok produces an exact expression for the oscillation by determining explicitly the evolution operator. These methods are compared to each other using the T2K, MINOS, NOνA, and LBNE parameters.Item Open Access Measurement of the total flux averaged neutrino induced neutral current elastic scattering cross section with the T2K Pi-Zero detector(Colorado State University. Libraries, 2014) Ruterbories, Daniel, author; Berger, Bruce E., advisor; Buchanan, Norman, committee member; Lear, Kevin, committee member; Wilson, Robert, committee memberTokai-to-Kamioka (T2K) is a second generation accelerator neutrino oscillation experiment. T2K uses a high intensity proton beam produced at the Japan Proton Accelerator Research Complex (J-PARC) incident on a carbon target and focused with three magnetic horns to produce a high intensity and nearly pure muon neutrino beam with a peak energy of 600 MeV at a 2.5º axis angle. The muon neutrino beam travels 295 km across Japan to the Super Kamiokande (SK) water Cherenkov detector in the Kamioka mine. The neutrino beam is also sampled by a complex of near detectors 280 m downstream of the carbon target located both on and off the beam axis. These detectors measure the neutrino beam before neutrino oscillations occur to provide input constraints to oscillation searches using SK. The off-axis near detector, ND280, is a composite detector made up of a tracker section and a Pi-Zero detector (PØD), all surrounded by an electromagnetic calorimeter. The entire detector is enclosed in a dipole magnet with a field of 0.2 T. The primary purpose of the tracker section is to measure neutrino induced charged current events characterized by the production of muons. The PØD is primarily designed to detect electromagnetic showers and to measure interactions on water through the use of a removable water target. In addition to these measurements, the ND280 detector is also used to study the cross sections of neutrino interactions on the various materials in the detectors. Limited knowledge of the cross sections in this neutrino energy regime are an important source of systematic error in neutrino oscillation measurements. This thesis presents a measurement of one neutrino interaction channel in the PØD, neutral current elastic scattering (NCE). In this process a neutrino elastically scatters off a proton or neutron in the target nucleus producing a proton or neutron with higher energy. The signature of this process is a single proton track. A particle identification algorithm (PID) was developed to suppress the dominant muon background. Using this algorithm in conjunction with a Michel electron veto the flux averaged absolute cross section is measured to be <σ>flux =2.24×10-39 cm2,nucleon ±0.07(stat.) +0.53,-0.63 (sys.).Item Open Access Measurement of νμ induced charged current inclusive cross section on water using the near detector of the T2K experiment(Colorado State University. Libraries, 2016) Das, Rajarshi, author; Toki, Walter, advisor; Wilson, Robert, committee member; Berger, Bruce, committee member; Menoni, Carmen, committee memberThe Tokai to Kamioka (T2K) Experiment is a long-baseline neutrino oscillation experiment located in Japan with the primary goal to measure precisely multiple neutrino flavor oscillation parameters. An off-axis muon neutrino beam peaking at 600 MeV is generated at the JPARC facility and directed towards the 50 kiloton Super-Kamiokande (SK) water Cherenkov detector located 295 km away. Measurements from a Near Detector that is 280m downstream of the neutrino beam target are used to constrain uncertainties in the beam flux prediction and neutrino interaction rates. We present a selection of inclusive charged current neutrino interactions on water. We used several sub-detectors in the ND280 complex, including a Pi-Zero detector (P0D) that has alternating planes of plastic scintillator and water bag layers, a time projection chamber (TPC) and fine-grained detector (FGD) to detect and reconstruct muons from neutrino charged current events. We use a statistical subtraction method with the water-in and water-out inclusive selection to extract a flux-averaged, νμ induced, charged current inclusive cross section. We also outline the evaluation of systematic uncertainties. We find an absolute cross section of ⟨σ⟩Φ = (6.37 ± 0.157(stat.) (−1.060/+0.910(sys.)) × 10−39 (cm2/H2O nucleon). This is the first νμ charged current inclusive cross section measurement on water.Item Open Access Neutron/muon correlation functions to improve neutron detection capabilities outside nuclear facilities(Colorado State University. Libraries, 2016) Ordinario, Donald Thomas, author; Brandl, Alexander, advisor; Johnson, Thomas, committee member; Wilson, Robert, committee memberThe natural neutron background rate is largely due to cosmic ray interactions in the atmosphere and the subsequent neutron emission from the interaction products. The neutron background is part of a larger cosmic radiation shower that also includes electrons, gamma rays, and muons. Since neutrons interact much differently than muons in building materials, the muon and neutron fluence rates in the natural background can be compared to the measured muon and neutron fluence rate when shielded by common building materials. The simultaneous measurement of muon and neutron fluence rates might allow for an earlier identification of man-made neutron sources, such as hidden nuclear materials. This study compares natural background neutron rates to computer simulated neutron rates shielded by common structural and building materials. The characteristic differences between neutrons and muons resulted in different attenuation properties under the same shielded conditions. Correlation functions between cosmic ray generated neutrons and muons are then used to predict neutron fluence rates in different urban environments.Item Unknown Qualification of silicon photomultipliers and readout boards for use in protoDUNE photon detectors(Colorado State University. Libraries, 2018) Johnson, Connor, author; Buchanan, Norm, advisor; Wilson, Robert, committee member; Brandl, Alexander, committee memberThe study of neutrinos is a major component of modern High Energy Physics research. Neutrinos have been shown to have properties not predicted by the Standard Model, such as having non-zero mass. The Deep Underground Neutrino Experiment (DUNE) is a project in development which seeks to better understand neutrino physics. Part of the project includes designing a prototype detector for testing at CERN, which has been dubbed protoDUNE. Both DUNE and protoDUNE will consist of liquid argon time projection chambers, and a photon detection system. The photosensors used in the photon detection system will need to be submerged in cryogenic liquid, and will have to undergo thermal cycling as many as 5 times through their lifetime. The design installed in protoDUNE will use SensL C-Series SiPMs as photosensors, which have not been rated to operate below −40°C. This project sought to determine how these devices operate under repeated thermal cycles. Mounting boards were designed to measure the SiPM operation, and a cold test system was built which allows for repeated thermal cycling of these boards and their SiPMs. The data were closely examined to search for any issues arising, in particular searching for any problems consistent with damage to the SiPMs.