Physics Commons^™

Applications Of Independent And Identically Distributed (Iid) Random Processes In Polarimetry And Climatology, Dan Kestner

Dissertations, Master's Theses and Master's Reports

The unifying theme of this thesis is the characterization of “perfect randomness,” i.e., independent and identically distributed (IID) stochastic processes as these are applied in physical science. Two specific and mathematically distinct applications are chosen: (i) Radar and optical polarimetry; (ii) Analysis of time series in meteorology. In (i), IID process of a special kind, namely, with a distribution defined by symmetry, is used to link its multivariate Gaussian density to uniformity on the Poincaré sphere. This “statistical ellipsometry” approach is then used to relate polarimetric mismatches or imbalances to ellipsometric variables and suitably chosen cross-correlation measures. In (ii), recently …

Extending The Lifetime Of Optically Stimulated Dosimeters For Use In Output Checks At Iroc- Houston, Hayden Scott

Dissertations & Theses (Open Access)

Purpose: Optically Stimulated Luminescent Dosimeters (OSLDs) are a prominent form of in-vivo dosimeter used both in clinics as well as for the audits of radiological
equipment at the Imaging and Radiation Oncology Core (IROC)-Houston. These
dosimeters have a recommended dose limit of 10 Gy due to a change in signal response with dose. To assist with the OSLD operation at IROC-Houston, evaluating the signal response of these dosimeters with IROC’s methodologies offers the potential to extend the dose limit past 10 Gy, improve the efficiency of handling OSLDs, and reduce the cost and time spent on commissioning OSLDs.
Methods: The …

Gamma Calibration Of Scintillators For The Muon Scattering Experiment, Anne Gloria Flannery

Theses and Dissertations

The MUon Scattering Experiment (MUSE) at the Paul Scherrer Institute seeks to measure the muon-proton and electron-proton elastic cross-sections in the same experiment by measuring the scattering angle of particles from a 115-160 MeV beam onto a liquid hydrogen target. The timing detectors, as well as several of other detectors in the experiment, are plastic scintillators. This document discusses a method for the energy calibration, using ²⁰⁸Tl, ²²Na, and 88Y sources, signal attenuation, and hit-position reconstructions of various timing detectors, as well as their function in the experiment as a whole. This method involves first attaining the pulse-height …

Calibration Of The Lux-Zeplin Dual-Phase Xenon Time Projection Chamber With Internally Injected Radioisotopes, Christopher D. Nedlik

Doctoral Dissertations

Self-shielding in ton-scale liquid xenon (LXe) detectors presents a unique challenge for calibrating detector response to interactions in the detector's innermost volume. Calibration radioisotopes must be injected directly into the LXe to reach the central volume, where they must either decay away with a short half life or be purified out. We present an overview of, and results from, the prototype source injection system (SIS) developed at the University of Massachusetts Amherst for the LUX-ZEPLIN experiment (LZ). The SIS is designed to refine techniques for the injection and removal of precise activities of various calibration radioisotopes that are useful in …

Location And Calibration Of Lightning Pulses From Lofar Radiation Measurements, Nicholas R. Demers

Honors Theses and Capstones

Lightning has the power to shock and awe as an incredible force of nature, yet so many phenomena surrounding lightning are still not well-understood. In fact, the very physics regarding what actually sparks a lightning strike remain poorly defined. In an effort to understand how lightning initiation is achieved, data collected from the Low Frequency Array in the Netherlands were calibrated and interferometry performed to map the flash in 4D space. The calibration process itself is explored, from choosing lightning sources to calibrate, to the various stages of calibration leading to a fully calibrated flash ready for interferometric analysis. Using …

Reduced Calibration Uncertainties For The Global Network Of Gravitational-Wave Observatories And The Impact On Sky Localization Of Burst-Like Sources, Dripta Bhattacharjee

Doctoral Dissertations

The Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) is a science facility in the United States devoted to the observation of gravitational waves (GWs). It comprises two kilometer-scale laser interferometers. It is a part of a global ground-based GW detector network that also includes Virgo in Italy and KAGRA in Japan. Calibration of the LIGO detectors is achieved using displacement fiducials generated by radiation pressure based systems called Photon Calibrators (Pcals). The first part of this research described here details the developments implemented during the third LIGO-Virgo-KAGRA (LVK) observation run, O3, in the propagation of laser power calibration via transfer standards …

Calibration Transients In Ligo Detectors, Thomas Daniel Abbott

LSU Doctoral Dissertations

This dissertation describes a novel method of analyzing fluctuations in the time-dependent calibration models of the LIGO interferometers to estimate their effect on strain reconstruction for gravitational-wave detections. The time-dependence of the calibration model of each detector is tracked with a set of parameters which are continuously measured while the interferometers are operating. These parameters track slow variations in the sensing function of the detectors as well as the actuators that hold the detectors in an operational state. The time-dependent parameter data during the second observation run (O2 [November 30, 2016 16:00 UTC to August 25, 2017 22:00:00 UTC]) and …

Optimizing Advanced Ligo's Scientific Output With Fast, Accurate, Clean Calibration, Aaron Daniel Viets

Theses and Dissertations

Since 2015, the direct observation of gravitational waves has opened a new window to observe the universe and made strong-field tests of Einstein's general theory of relativity possible for the first time. During the first two observing runs of the Advanced gravitational-wave detector network, the Laser Interferometer Gravitational-wave Observatory (LIGO) and the Virgo detector have made 10 detections of binary black hole mergers and one detection of a binary neutron star merger with a coincident gamma-ray burst. This dissertation discusses methods used in low and high latency to produce Advanced LIGO's calibrated strain data, highlighting improvements to accuracy, latency, and …

Determination Of Conversion Factors For Various Calibration Geometries Using Barium-133 In A Silver Zeolite Cartridge, Amin Hamideh

LSU Master's Theses

Iodine-131 (I-131) is a major fission product among other radionuclides released during a nuclear incident. This radioiodine has a half-life of 8.02 days and the primary organ of uptake through ingestion or inhalation is the thyroid gland. For these reasons, nuclear power plants must routinely monitor I-131 through air sampling. Currently, there are two adsorbing media to collect I-131: activated charcoal and silver zeolite cartridges. Silver zeolite cartridges are generally used during a post nuclear incident due to its affinity for iodine while not adsorbing noble gases such as krypton-85 and xenon-135. After an air sample is taken from a …

The Search For Dark Matter In Xenon: Innovative Calibration Strategies And Novel Search Channels, Shayne Edward Reichard

Open Access Dissertations

The direct detection dark matter experiment XENON1T became operational in early 2016, heralding the era of tonne-scale dark matter detectors. Direct detection experiments typically search for elastic scatters of dark matter particles off target nuclei. XENON1T's larger xenon target provides the advantage of stronger dark matter signals and lower background rates compared to its predecessors, XENON10 and XENON100; but, at the same time, calibration of the detector's response to backgrounds with traditional external sources becomes exceedingly more difficult.

A 220Rn source is deployed on the XENON100 dark matter detector in order to address the challenges in calibration of tonne-scale liquid …

Experimental Analysis Of Energy-Based Acoustic Arrays For Measurement Of Rocket Noise Fields, Jarom Henry Giraud

Theses and Dissertations

Microphone arrays are useful for measuring acoustic energy quantities (e.g. acoustic intensity) in the near-field of a full-scale solid rocket motor. Proper characterization of a rocket plume as a noise source will allow for more accurate predictions in engineering models that design for protection of structures, payloads and personnel near the rockets. Acoustic intensity and energy density quantities were measured in three rocket noise fields and have shown that the apparent source region of the rocket becomes smaller and moves upstream as frequency increases. Theoretical results accounting for some scattering and finite-difference errors arising in these types of energy-based measurements …

Algorithm Development Of The Aglite-Lidar Instrument, Christian Marchant

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Particulate emissions from agricultural operations are increasingly receiving attention from regulatory bodies as a potential source of air pollution. The Space Dynamics Laboratory (SDL) has developed the Aglite system, a suite of instruments including a lidar that is capable of measuring particulate emission levels from agricultural facilities. This system provides a novel method of measuring particulate mass (PM) pollution, allowing measurements to be taken of diverse types of facilities with high temporal and spatial resolution. This high resolution allows for the measurement of emission levels generated by specific activities, fostering the development and determination of best management practices.

The Aglite …