Plasma Diagnostics For Anode Cathode Plasmas And High Energy Density Physics On A Linear Transformer Driver,
2024
University of New Mexico - Main Campus
Plasma Diagnostics For Anode Cathode Plasmas And High Energy Density Physics On A Linear Transformer Driver, Robert Beattie-Rossberg
Electrical and Computer Engineering ETDs
A twelve-brick air insulated linear transformer driver (LTD) was characterized by charging to voltages ranging from 30 to 70 kV and delivering energy to two separate resistive loads. Various plasma diagnostics were built and fielded with an emphasis on the design, implementation and analysis of a Mach Zehnder interferometer, a moiré deflectometer and a spectroscopy system providing information on the temporal evolution of plasma electron density and atomic composition. Rogowski coils, XRD radiation detectors, framing camera images and time integrated DSLR images are used to further understand load conditions where current data, x ray radiation data, velocity data and instability …
Implementation Of Python Based High Voltage Tests For Gem Detectors,
2024
Florida Institute of Technology
Implementation Of Python Based High Voltage Tests For Gem Detectors, John Paul Hernandez
Aerospace, Physics, and Space Science Student Publications
The Compact Muon Solenoid, CMS, and other detectors at LHC are in the process of being upgraded for the HL-LHC (High-Luminosity Large Hadron Collider) which will produce more than 5 times the particle interactions than of the current LHC. One upgrade to CMS is the introduction of new GEM detectors (Gaseous Electron Multiplier), GE2/1 and ME0 shown at right are new detectors to CMS and therefore must be tested thoroughly prior to being installed.
Float Like A Butterfly, Sting Like A Bee!,
2024
Fort Hays State
Float Like A Butterfly, Sting Like A Bee!, Kobe D. Rome
SACAD: Scholarly Activities
By injecting an electron into the empty pie* molecular orbital (LUMO) of Amino Acids in gas phase, we measure the Vertical Attachment Energies (VAEs) for the formation of short-lived anion states of these species using electron transmission spectroscopy (ETS). Our ETS study, a first of its kind to measure the VAE for the simplest of proteins, Glycine-Glycine (Gly-Gly), is currently in progress. Based on our previous measurements for several Amino Acids including Glycine, we expect a common range of attachment energy (1.50 – 2.00 eV) for Gly-Gly.
All-Optical Probes Of Particle-Like Charge Migration Dynamics,
2024
Louisiana State University and Agricultural and Mechanical College
All-Optical Probes Of Particle-Like Charge Migration Dynamics, Kyle A. Hamer
LSU Doctoral Dissertations
Particle-like charge migration (CM) is the coherent, back-and-forth motion of a positively-charged electron hole along the backbone of a molecule following a sudden ionization. CM in small molecules generally occurs on an Angstrom (10-10 m) spatial scale and an attosecond (10-18 s) timescale. I use time-dependent density-functional theory (TDDFT) to simulate CM modes in organic molecules, and to explore all-optical probes of this attosecond electron dynamics using high-harmonic spectroscopy (HHS). By leveraging my results from previous studies of two-center interferences in carbon dichalcogens, in which I separated the harmonic signal into contributions from individual Kohn-Sham orbitals, I first …
Nowcasting Solar Euv Irradiance With Photospheric Magnetic Fields And The Mg Ii Index,
2024
Air Force Instittue of Technology
Nowcasting Solar Euv Irradiance With Photospheric Magnetic Fields And The Mg Ii Index, Kara L. Kniezewski, Samuel J. Schonfeld, Carl J. Henney
Student Publications
A new method to nowcast spectral irradiance in extreme ultraviolet (EUV) and far ultraviolet (FUV) bands is presented here, utilizing only solar photospheric magnetograms and the Mg II index (i.e., the core-to-wing ratio). The EUV and FUV modeling outlined here is a direct extension of the SIFT (Solar Indices Forecasting Tool) model, based on Henney et al. (2015, https://doi.org/10.1002/2014sw001118). SIFT estimates solar activity indices using the earth-side solar photospheric magnetic field sums from global magnetic maps generated by the ADAPT (Air Force Data Assimilative Photospheric Flux Transport) model. Utilizing strong and weak magnetic field sums from ADAPT maps, Henney …
Group Iv Topological Quantum Alloy And The Role Of Short-Range Order: The Case Of Ge-Rich Ge1–XPbX,
2024
Rensselaer Polytechnic Institute
Group Iv Topological Quantum Alloy And The Role Of Short-Range Order: The Case Of Ge-Rich Ge1–XPbX, Yunfan Liang, Shunda Chen, Xiaochen Jin, Damien West, Shui-Qing Yu, Tianshu Li, Shengbai Zhang
Electrical Engineering and Computer Science Faculty Publications and Presentations
Despite the explosion of interest in topological materials over the last decades, their applications remain limited due to challenges in growth and incorporation with today’s microelectronics. As a potential bridge to close this gap, we investigate the group-IV alloy Ge1–xPbx, in the Ge-rich condition using density functional theory and show that relatively low concentrations of Pb (~9.4%) can lead to a topological phase transition. Furthermore, the calculation of the Z2 invariant for both the random alloy and the alloy with short-range order (SRO) indicate that the topological phase of the material can be directly modified …
Modeling And Numerical Analysis Of The Cholesteric Landau-De Gennes Model,
2024
Louisiana State University and Agricultural and Mechanical College
Modeling And Numerical Analysis Of The Cholesteric Landau-De Gennes Model, Andrew L. Hicks
LSU Doctoral Dissertations
This thesis gives an analysis of modeling and numerical issues in the Landau-de Gennes (LdG) model of nematic liquid crystals (LCs) with cholesteric effects. We derive various time-step restrictions for a (weighted) $L^2$ gradient flow scheme to be energy decreasing. Furthermore, we prove a mesh size restriction, for finite element discretizations, that is critical to avoid spurious numerical artifacts in discrete minimizers that is not well-known in the LC literature, particularly when simulating cholesteric LCs that exhibit ``twist''. Furthermore, we perform a computational exploration of the model and present several numerical simulations in 3-D, on both slab geometries and spherical …
Advancements In Characterization Of Ancient Potteries From Southeast Asia: A Review Of Analytical Techniques,
2024
Division of Physics, School of Science, Walailak University, Nakhon Si Thammarat 80160, Thailand
Advancements In Characterization Of Ancient Potteries From Southeast Asia: A Review Of Analytical Techniques, Chitnarong Sirisathitkul
Makara Journal of Science
Ancient potteries offer valuable information regarding technological advancements, life dynamics, cultural diversity, and trade routes in the past. Earthenware, stoneware, and porcelain from Southeast Asia have been characterized using several analytical techniques, as reviewed in this article. Fluorescent and diffracted X-rays give rise to elemental and phase compositions, respectively. Examination of molecular bonds requires vibrational spectroscopy, which is useful for the identification of organic materials in ancient potteries. With the advent of portable X-ray fluorescence and Raman spectrometry, on-site analysis of archeological ceramics is now possible. For in-depth analysis, synchrotron light sources can provide new insights into artifacts through X-ray …
Size Limits And Fission Channels Of Doubly Charged Noble Gas Clusters,
2024
University of Innsbruck
Size Limits And Fission Channels Of Doubly Charged Noble Gas Clusters, Ianessa Stromberg, Stefan Bergmeister, Lisa Ganner, Fabio Zappa, Paul Scheier, Olof Echt, Elisabeth Gruber
Faculty Publications
Small, highly charged liquid droplets are unstable with respect to spontaneous charge separation when their size drops below the Rayleigh limit or, in other words, their fissility parameter X exceeds the value 1. The absence of small doubly charged atomic cluster ions in mass spectra below an element-specific appearance size na has sometimes been attributed to the onset of barrierless fission at X = 1. However, more realistic models suggest that na marks the size below which the rate of fission surpasses that of competing dissociative channels, and the Rayleigh limit of doubly charged van der Waals clusters …
Spectroscopic End Point Detection With An Electron Beam Evaporator,
2024
Portland State University
Spectroscopic End Point Detection With An Electron Beam Evaporator, Ryan Mcgraw
University Honors Theses
Spectroscopic end point detection is a common tool used for measuring slope changes in wavelength intensity. Using algorithms able to apply this concept, coatings will be able to be dynamically measured in real time and stopped at the appropriate level to ensure process uniformity. It is currently applied to reductive processes such as etching, where the surface will start to be eaten away, creating a plasma. When the entire amount of a material on a substrate has been eaten away, the plasma will change color as it is beginning to etch a different material. Using a spectrometer, this point where …
Doubly Charged Dimers And Trimers Of Heavy Noble Gases,
2024
University of Innsbruck
Doubly Charged Dimers And Trimers Of Heavy Noble Gases, Gabriel Schöpfer, Stefan Bergmeister, Milan Ončák, Ianessa Stromberg, Masoomeh Mahmoodi-Darian, Paul Scheier, Olof Echt, Elisabeth Gruber
Faculty Publications
Many doubly charged heteronuclear dimers are metastable or even thermodynamically stable with respect to charge separation. Homonuclear dicationic dimers, however, are more difficult to form. He22+ was the first noble gas dimer predicted to be metastable and, decades later, observed. Ne22+ is the only other dicationic noble gas dimer that has been detected so far. Here, we present a novel approach to form fragile dicationic species, by post-ionization of singly charged ions that are embedded in helium nanodroplets (HNDs). Bare ions are then extracted by colliding the HNDs with helium gas. We detect homonuclear doubly charged …
Stoner Instability-Mediated Large Magnetoelectric Effects In 2d Stacking Electrides,
2024
Southern University of Science & Technology, Shenzhen, Guangdong, China
Stoner Instability-Mediated Large Magnetoelectric Effects In 2d Stacking Electrides, Zhigang Gui, Haiyan Zhu, Zhe Wang, M. Umar Farooq, Laurent Bellaiche, Li Huang
Physics Faculty Publications and Presentations
Strong magnetoelectric effects in single-phase two-dimensional (2D) materials are extremely rare in nature. Here by first-principles calculations, we find a strong magnetoelectric coupling in polar stacking bilayer Hf2S that allows the reversal of net magnetic moments with the reversal of electric dipoles. Further analysis shows that such strong magnetoelectric effects benefit from the Stoner instability of surface Hf atoms triggered by polar stacking. Moreover, an unexpectedly large out-of-plane electric polarization (which is at least two times larger than that of bilayer BN) survives in the material, despite its metallicity. The large electric polarization is ascribed to the delocalized …
Global Empirical Model Of Sporadic-E Occurrence Rates,
2024
Air Force Institute of Technology
Global Empirical Model Of Sporadic-E Occurrence Rates, Eli V. Parsch
Theses and Dissertations
Encompassing the Earth, the ionosphere presents unique challenges to modern communication, navigation, and surveillance technologies. Intense ionization enhancements known as sporadic-E (Es), can degrade and disrupt signals in unpredictable ways. Much work has been done to understand this phenomenon and more recent efforts have attempted to model its behavior and impacts. However, there have been limited efforts at modeling global Es occurrence rates (OR) at high time resolutions. This study develops a global empirical model of blanketing sporadic-E (fbEs) occurrence rates using a Karhunen-Lo´eve Expansion (KLE) of global fbEs OR climatologies built with Global Positioning System radio occultations (GPS-RO) and …
Neutron Spectrum Unfolding From Activation Foils Irradiated In Gamble Ii Using Deuterated Polyethylene Anodes,
2024
Air Force Institute of Technology
Neutron Spectrum Unfolding From Activation Foils Irradiated In Gamble Ii Using Deuterated Polyethylene Anodes, Christopher J. Smith
Theses and Dissertations
Neutrons can cause irreparable harm to electronics, and experiments are needed to understand their effects fully. This work explores using pulsed power, which is low-cost compared to other sources, to create a useful neutron-rich environment. Deuterated polyethylene was used as anode and catcher material to generate the neutrons from the Deuterium-Deuterium (DD) fusion reaction. A simple, effective, and repeatable method was employed to directly cast deuterated polyethylene onto polyethylene sheets to fabricate the anode and catcher. The DD reactions were made by an ion beam-driven pulsed power generator, Gamble II, with the catcher located in the cathode. Zinc, copper, aluminum, …
Analyzing The Effects Of Atmospheric Turbulence On Polarization-Entangled Photon Pairs Using Quantum State Tomography,
2024
Air Force Institute of Technology
Analyzing The Effects Of Atmospheric Turbulence On Polarization-Entangled Photon Pairs Using Quantum State Tomography, Noah S. Everett
Theses and Dissertations
To help in building a quantum-based communication link, we experimentally designed a system to simulate atmospheric turbulence and characterize its effects on a polarization-entangled photon-pair source. The simulated turbulence is constructed using two afocal optical systems with a phase plate inserted in each to mimic both weak and strong atmospheric turbulence respectively. After propagation, quantum state tomography (QST) is performed on each pair to reconstruct the density matrix of the pair’s overall polarization state. In characterization of the simulated turbulence, we were able to reach strengths up to a D/r0 of 18.2, which begins to approach the strong turbulent regime. …
Developing A Remote Gamma-Ray Spectra Collection System (Rgscs) By Coupling A High Purity Germanium (Hpge) Detector With A Cosmicguard Background Reduction Device,
2024
University of Nevada, Las Vegas
Developing A Remote Gamma-Ray Spectra Collection System (Rgscs) By Coupling A High Purity Germanium (Hpge) Detector With A Cosmicguard Background Reduction Device, Zaijing Sun, Krishnakumar Divakar Nangeelil, Haven Searcy
Health Physics and Diagnostic Sciences Faculty Research
Despite being widely used for high-resolution spectral analysis and quantifying low activity in natural samples, the operations and data analysis of High Purity Germanium (HPGe) gamma-ray detectors are seldom fully automated due to the excessive costs associated with commercially available automatic sample changing systems. This paper introduces the design and implementation of a cost-effective, customized remote gamma-ray spectra collection system centered around the HPGe detector coupled to a cosmic-ray veto background reduction device. The HPGe detector system, equipped with a Lynx DSA, is seamlessly integrated with an economically viable automatic sample changer. This sample vial changer is controlled by a …
On The Exact Helium Wave Function Expansion, Ii, An Exponential Modulated Form,
2024
University of Connecticut
On The Exact Helium Wave Function Expansion, Ii, An Exponential Modulated Form, Carl W. David
Chemistry Education Materials
A 11S wave function’s expansion for 2 electron atoms and ions is proposed employing an appropriate exponential factor and Fock’s logarithmic terms. The leading coefficient’s are presented.
Some Remarks On Possible Superconductivity Of Composition Pb9Cup6O25,
2024
CIEMAT, Madrid
Some Remarks On Possible Superconductivity Of Composition Pb9Cup6O25, Pablo Abramian-Barco, A. Kuzanyan, Vahan Nikoghosyan, Serafim Teknowijoyo, Armen Gulian
Mathematics, Physics, and Computer Science Faculty Articles and Research
A material called LK-99, a modified-lead apatite crystal structure with the composition Pb10 – xCux(PO4)6O (0.9 < x < 1.1) has been reported to be an above-room-temperature superconductor at ambient pressure. It is hard to expect that it will be straightforward for other groups to reproduce the original results. We provide here some remarks which may be helpful for a success.
Phase-Slip Centers As Cooling Engines,
2024
Chapman University
Phase-Slip Centers As Cooling Engines, Iris Mowgood, Serafim Teknowijoyo, Sara Chahid, Armen Gulian
Mathematics, Physics, and Computer Science Faculty Articles and Research
Based on time-dependent Ginzburg-Landau system of equations, Éliashberg’s kinetic equations and finite element modeling, we analyze phonon emission by the phase-slip centers in superconducting filaments. Our results show that in the dissipative regime with these centers, thin superconducting filaments can be effective in originating not only positive but also negative thermal fluxes, i.e., they both generate and absorb phonons. In a stationary oscillatory regime, at a given moment of time, this generation and absorption of phonons reveals itself as positive and negative spectrum of phonons at different spectral ranges. Moreover, at a given spectral range, the emission reverses its sign …
Superconducting Polycrystalline Rhenium Films Deposited At Room Temperature,
2024
Chapman University
Superconducting Polycrystalline Rhenium Films Deposited At Room Temperature, Serafim Teknowijoyo, Armen Gulian
Mathematics, Physics, and Computer Science Faculty Articles and Research
We report on magnetron deposition of thin superconducting rhenium films on sapphire substrates. During the deposition, substrates were held at ambient temperature. Critical temperature of the films is Tc ~ 3.6 K. Films have polycrystalline structure, and grazing incidence X-ray diffractometry indicates that crystalline lattice parameters are somewhat larger compared to the bulk ones. Magnetoresistive and AC/DC susceptibilities allowed us to determine Hc1 and Hc2 of these films, as well as estimate coherence length ξ(0) and magnetic penetration depth λL(0). We also provide information on surface morphology of these films.
