Analyses Of 476 Mhz And 952 Mhz Crab Cavities For Jlab Electron Ion Collider,
2016
Old Dominion University
Analyses Of 476 Mhz And 952 Mhz Crab Cavities For Jlab Electron Ion Collider, Hyekyoung Park, A. Castilla, J. R. Delayen, S. U. De Silva, V. Morozov
Physics Faculty Publications
Center for Accelerator Science at ODU has designed, fabricated and successfully tested a crab cavity for MEIC at Jefferson Lab*. This proof of principle cavity was based on the earlier MEIC design which used 748.5 MHz RF system. The updated MEIC design** utilizes the components from PEP-II. It results in the change on the bunch repetition rate of stored beam to 476.3 MHz. The ion ring collider will eventually require 952.6 MHz crab cavity. This paper will present the analyses of crab cavities of both 476 MHz and 952 MHz options. It compares advantages and disadvantages of the options which …
Simulation Of Nuclear Fusion Using A One Dimensional Particle In Cell Method,
2016
Humboldt State University
Simulation Of Nuclear Fusion Using A One Dimensional Particle In Cell Method, Steven T. Margell
Cal Poly Humboldt theses and projects
In this thesis several novel techniques are developed to simulate fusion events in an isotropic, electrostatic three-dimensional Deuterium-Tritium plasma. These techniques allow us to accurately predict three-dimensional collision events with a one-dimensional model while simultaneously reducing compute time via a nearest neighbor algorithm. Furthermore, a fusion model based on first principles is developed that yields an average fusion reactivity which correlates well with empirical results.
Theoretical Estimates Of Spherical And Chromatic Aberration In Photoemission Electron Microscopy,
2016
Portland State University
Theoretical Estimates Of Spherical And Chromatic Aberration In Photoemission Electron Microscopy, Joseph P. S. Fitzgerald, Robert Campbell Word, Rolf Kӧnenkamp
Physics Faculty Publications and Presentations
We present theoretical estimates of the mean coefficients of spherical and chromatic aberration for low energy photoemission electron microscopy (PEEM). Using simple analytic models, we find that the aberration coefficients depend primarily on the difference between the photon energy and the photoemission threshold, as expected. However, the shape of the photoelectron spectral distribution impacts the coefficients by up to 30%. These estimates should allow more precise correction of aberration in PEEM in experimental situations where the aberration coefficients and precise electron energy distribution cannot be readily measured.
20 Years Of Microplasma Research: A Status Report,
2016
Old Dominion University
20 Years Of Microplasma Research: A Status Report, Karl H. Schoenbach, Kurt Becker
Bioelectrics Publications
The field of microplasmas gained recognition as a well-defined area of research and application within the larger field of plasma science and technology about 20 years ago. Since then, the activity in microplasma research and applications has continuously increased. A survey of peer reviewed papers on microplasmas published annually shows a steady increase from fewer than 20 papers in 1995 to about 75 in 2005 and more than 150 in 2014. This count excludes papers that deal exclusively with technological applications where the microplasma is used solely as a tool. This topical review aims to provide a snap shot of …
Multicharged Carbon Ion Generation From Laser Plasma,
2016
Old Dominion University
Multicharged Carbon Ion Generation From Laser Plasma, Oguzhan Balki, Hani E. Elsayed-Ali
Electrical & Computer Engineering Faculty Publications
Carbon ions generated by ablation of a carbon target using an Nd:YAG laser pulse (wavelength λ = 1064 nm, pulse width τ = 7 ns, and laser fluence of 10-110 J cm-2) are characterized. Time-of-flight analyzer, a three-mesh retarding field analyzer, and an electrostatic ion energy analyzer are used to study the charge and energy of carbon ions generated by laser ablation. The dependencies of the ion signal on the laser fluence, laser focal point position relative to target surface, and the acceleration voltage are described. Up to C4+ ions are observed. When no acceleration voltage is applied between the …
Distributions Of Long-Lived Radioactive Nuclei Provided By Star-Forming Environments,
2015
Xavier University - Cincinnati
Distributions Of Long-Lived Radioactive Nuclei Provided By Star-Forming Environments, Marco Fatuzzo, Fred Adams
Faculty Scholarship
Radioactive nuclei play an important role in planetary evolution by providing an internal heat source, which affects planetary structure and helps facilitate plate tectonics. A minimum level of nuclear activity is thought to be necessary—but not sufficient—for planets to be habitable. Extending previous work that focused on short-lived nuclei, this paper considers the delivery of long-lived radioactive nuclei to circumstellar disks in star forming regions. Although the long-lived nuclear species are always present, their abundances can be enhanced through multiple mechanisms. Most stars form in embedded cluster environments, so that disks can be enriched directly by intercepting ejecta from supernovae …
Combining Diffusive Shock Acceleration And Stochastic Particle Energization By Multiple Plasmoids,
2015
University of Alabama in Huntsville
Combining Diffusive Shock Acceleration And Stochastic Particle Energization By Multiple Plasmoids, Parisa Mostafavi
Von Braun Symposium Student Posters
No abstract provided.
Electron Vortices In Photoionization By Circularly Polarized Attosecond Pulses,
2015
University of Nebraska-Lincoln
Electron Vortices In Photoionization By Circularly Polarized Attosecond Pulses, Jean Marcel Ngoko Djiokap, S. X. Hu, L. B. Madsen, N. L. Manakov, A. V. Meremianin, Anthony F. Starace
Anthony F. Starace Publications
Single ionization of He by two oppositely circularly polarized, time-delayed attosecond pulses is shown to produce photoelectron momentum distributions in the polarization plane having helical vortex structures sensitive to the time delay between the pulses, their relative phase, and their handedness. Results are obtained by both ab initio numerical solution of the two-electron time-dependent Schrödinger equation and by a lowest-order perturbation theory analysis. The energy, bandwidth, and temporal duration of attosecond pulses are ideal for observing these vortex patterns.
Simulations Of Hl-Lhc Crab Cavity Noise Using Headtail,
2015
California Polytechnic State University - San Luis Obispo
Simulations Of Hl-Lhc Crab Cavity Noise Using Headtail, Stanley Steeper
Physics
The High Luminosity Large Hadron Collider (Hi-Lumi LHC) upgrade -- scheduled to be completed by 2025 -- will improve the existing LHC in many ways. One such upgrade is the addition of Crab Cavities (CCs). The CCs are resonant structures that provide strong transverse kicks to the circulating clouds of particles around each interaction region. As such, the CCs result in a head-on collision of the clouds and a large increase in event rate, leading to reduced statistical uncertainty and potentially faster discoveries. However, the CC field will be modulated by phase and amplitude noise which can have detrimental effects …
Kinetic Modeling Of Roll To Roll Rfcvd Plasma,
2015
Purdue University
Kinetic Modeling Of Roll To Roll Rfcvd Plasma, Kudzo S. Ahegbebu, Siva Sashank Tholeti, Alina A. Alexeenko
The Summer Undergraduate Research Fellowship (SURF) Symposium
Roll-to-roll radio frequency plasma enhanced chemical vapor deposition (R2R RFCVD) is a technique for large-scale synthesis of high quality graphitic nanopetals. Graphitic nanopetals are petal-like graphene structures with remarkable electrical and mechanical properties with major industrial applications such as microsupercapacitors. RFCVD uses a non-equilibrium plasma with high energy electrons to catalyze chemical reactions, induce the creation of free radicals, and promote otherwise high temperature chemistry in a low temperature environment. Understanding how bulk plasma characteristics (particularly, power and number densities) vary with changing reactor parameters is an important step towards optimizing synthesis techniques. In our present work we use the …
Optical Emission Spectroscopy Diagnostics Of Cold Plasmas For Food Sterilization,
2015
Purdue University
Optical Emission Spectroscopy Diagnostics Of Cold Plasmas For Food Sterilization, Abhijit Jassem, Michael Lauria, Russell Brayfield Ii, Kevin M. Keener, Allen L. Garner
The Summer Undergraduate Research Fellowship (SURF) Symposium
There is a growing need for economical, effective, and safe methods of sterilizing fresh produce. The most common method is a chlorine wash, which is expensive and may introduce carcinogens. High voltage cold atmospheric pressure plasmas are a promising solution that has demonstrated a germicidal effect; however, the responsible chemical mechanisms and reaction pathways are not fully understood. To elucidate this chemistry, we used optical emission spectroscopy to measure the species produced in the plasma generated by a 60 Hz pulsed dielectric barrier discharge in a plastic box containing various fill gases (He, N2, CO2, dry …
Scaling Laws For High-Order-Harmonic Generation With Midinfrared Laser Pulses,
2015
Voronezh State University, Russia
Scaling Laws For High-Order-Harmonic Generation With Midinfrared Laser Pulses, M. V. Frolov, N. L. Manakov, Wei-Hao Xiong, Liang-You Peng, J. Burgdörfer, Anthony F. Starace
Anthony F. Starace Publications
We derive an analytic expression for thewavelength scaling of the high-order-harmonic generation (HHG) yield induced by midinfrared driving laser fields. It is based on a quasiclassical description of the returning electron wave packet, which is shown to be largely independent of atomic properties. The accuracy of this analytic expression is confirmed by comparison with results of numerical solutions of the time-dependent Schr¨odinger equation for wavelengths in the range of 1.4 μm ≤ λ ≤ 4 μm. We verify the wavelength scaling of the HHG yield found numerically for midinfrared laser fields in a recent paper by Le et al. [
Favorable Target Positions For Intense Laser Acceleration Of Electrons In Hydrogen-Like, Highly-Charged Ions,
2015
University of Nebraska-Lincoln
Favorable Target Positions For Intense Laser Acceleration Of Electrons In Hydrogen-Like, Highly-Charged Ions, Liang-Wen Pi, S. X. Hu, Anthony F. Starace
Anthony F. Starace Publications
Classical relativistic Monte Carlo simulations of petawatt laser acceleration of electrons bound initially in hydrogen-like, highly-charged ions show that both the angles and energies of the laser-accelerated electrons depend on the initial ion positions with respect to the laser focus. Electrons bound in ions located after the laser focus generally acquire higher (≈GeV) energies and are ejected at smaller angles with respect to the laser beam. Our simulations assume a tightly-focused linearly-polarized laser pulse with intensity approaching 1022W/cm2. Up to fifth order corrections to the paraxial approximation of the laser field in the focal region are …
Photodetachment Of A Model Molecular System By An Elliptically Polarized Field,
2015
Voronezh State University, Russia
Photodetachment Of A Model Molecular System By An Elliptically Polarized Field, M. V. Frolov, N. L. Manakov, S. S. Marmo, Anthony F. Starace
Anthony F. Starace Publications
The differential cross section for one-photon molecular detachment by an elliptically polarized field is analyzed for a one-electron molecular model comprised of an electron in the field of two (generally nonequivalent) attractive zero-range potentials (ZRPs) separated by the distance R. A phenomenological parametrization of the photodetachment cross section for a fixed-in-space molecular system in terms of two scalar dynamical parameters is presented and circular dichroism effects are discussed. Analytic results for the dynamical molecular parameters within the ZRP molecular model are used to analyze interference phenomena (including two-center interference) and dichroic effects in the detached electron angular distributions and …
Auto-Concealment Of Supersymmetry In Extra Dimensions,
2015
Stanford University
Auto-Concealment Of Supersymmetry In Extra Dimensions, Savas Dimopoulos, Kiel Howe, John March-Russell, James A. Scoville
Faculty Publications
In supersymmetric (SUSY) theories with extra dimensions the visible energy in sparticle decays can be significantly reduced and its energy distribution broadened, thus significantly weakening the present collider limits on SUSY. The mechanism applies when the lightest supersymmetric particle (LSP) is a bulk state — e.g. a bulk modulino, axino, or gravitino — the size of the extra dimensions ≳ 10−14 cm, and for a broad variety of visible sparticle spectra. In such cases the lightest ordinary supersymmetric particle (LOSP), necessarily a brane-localised state, decays to the Kaluza-Klein (KK) discretuum of the LSP. This dynamically realises the compression mechanism …
Electron Transmission Through Micrometer Sized Funnelshaped Tapered Glass Capillaries And Electron Micro-Beam Production,
2015
Western Michigan University
Electron Transmission Through Micrometer Sized Funnelshaped Tapered Glass Capillaries And Electron Micro-Beam Production, Samanthi Jayamini Wickramarachchi
Dissertations
The prime motivation of this work is to understand the fundamental transmission process of an electron beam through a funnel-shaped capillary taking into account its shape together with the energy, angular and time dependence of the transmitted electrons produce a microsized electron beam. The utilized capillaries had inlet/outlet diameters of 800/16 μm, 800/100 μm and lengths of 35 mm. Considerable transmission of 800 and 1000 eV electrons for tilt angles up to 1.5o and only small transmission for 500 eV electrons was observed for the capillary with the smaller outlet diameter of 16 μm. Incident electrons with energies of …
Power-Recycled Weak-Value-Based Metrology,
2015
University of Rochester
Power-Recycled Weak-Value-Based Metrology, Kevin Lyons, Justin Dressel, Andrew N. Jordan, John C. Howell, Paul G. Kwiat
Mathematics, Physics, and Computer Science Faculty Articles and Research
We improve the precision of the interferometric weak-value-based beam deflection measurement by introducing a power recycling mirror, creating a resonant cavity. This results in all the light exiting to the detector with a large deflection, thus eliminating the inefficiency of the rare postselection. The signal-to-noise ratio of the deflection is itself magnified by the weak value. We discuss ways to realize this proposal, using a transverse beam filter and different cavity designs.
Rescattering Effects In Laser-Assisted Electron-Atom
Bremsstrahlung,
2015
Voronezh State University, Russia
Rescattering Effects In Laser-Assisted Electron-Atom Bremsstrahlung, A. N. Zheltukhin, A. V. Flegel, M. V. Frolov, N. L. Manakov, Anthony F. Starace
Anthony F. Starace Publications
Rescattering effects in non-resonant spontaneous laser-assisted electron–atom bremsstrahlung (LABrS) are analyzed within the framework of time-dependent effective-range (TDER) theory. It is shown that high energy LABrS spectra exhibit rescattering plateau structures that are similar to those that are well-known in strong field laser-induced processes as well as those that have been predicted theoretically in laser-assisted collision processes. In the limit of a low-frequency laser field, an analytic description of LABrS is obtained from a rigorous quantum analysis of the exact TDER results for the LABrS amplitude. This amplitude is represented as a sum of factorized terms involving three factors, each …
Dual-Spacecraft Reconstruction Of A Three-Dimensional Magnetic Flux Rope At The Earth's Magnetopause,
2015
Japan Aerospace Exploration Agency
Dual-Spacecraft Reconstruction Of A Three-Dimensional Magnetic Flux Rope At The Earth's Magnetopause, H. Hasegawa, B. U. Ö. Sonnerup, S. Eriksson, T. K. M. Nakamura
Dartmouth Scholarship
We present the first results of a data analysis method, developed by Sonnerup and Hasegawa (2011), for reconstructing three-dimensional (3-D), magnetohydrostatic structures from data taken as two closely spaced satellites traverse the structures. The method is applied to a magnetic flux transfer event (FTE), which was encountered on 27 June 2007 by at least three (TH-C, TH-D, and TH-E) of the five THEMIS probes near the subsolar magnetopause. The FTE was sandwiched between two oppositely directed reconnection jets under a southward interplanetary magnetic field condition, consistent with its generation by multiple X-line reconnection. The recovered 3-D field indicates that a …
Evaluation Of Magnesium As A Hall Thruster Propellant,
2015
Michigan Technological University
Evaluation Of Magnesium As A Hall Thruster Propellant, Mark A. Hopkins
Dissertations, Master's Theses and Master's Reports - Open
In this study, the use of magnesium as a Hall thruster propellant was evaluated. A xenon Hall thruster was modified such that magnesium propellant could be loaded into the anode and use waste heat from the thruster discharge to drive the propellant vaporization. A control scheme was developed, which allowed for precise control of the mass flow rate while still using plasma heating as the main mechanism for evaporation. The thruster anode, which also served as the propellant reservoir, was designed such that the open area was too low for sufficient vapor flow at normal operating temperatures (i.e. plasma heating …
