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Confinement of antiprotons in the electrostatic space charge of positrons in a model of the ALPHA antihydrogen trap
This article details the equilibrium of a positron plasma in a model of the ALPHA apparatus that is computed using a finite-difference method. The positron plasma in the model extends to axial magnetic mirrors in absence of an octupole field. Formation of a three-dimensional electrostatic potential well is found to occur self-consistently. Well depths under various conditions are evaluated. Also, the equilibrium with an antiproton plasma confined in the potential well is computed.
Date:
March 17, 2016
Creator:
Lane, Ryan A. & Ordonez, Carlos A.
Object Type:
Article
System:
The UNT Digital Library
Artificially Structured Boundary for a high purity ion trap or ion source
This article proposes a plasma enclosed by an Artificially Structured Boundary (ASB) as an alternative to existing ion source assemblies. In accelerator applications, many ion sources can have a limited lifetime or frequent service intervals due to sputtering and eventual degradation of the ion source assembly. Ions are accelerated towards the exit canal of positive ion sources, whereas, due to the biasing scheme, electrons or negative ions are accelerated towards the back of the ion source assembly.
Date:
March 27, 2014
Creator:
Pacheco, J. L.; Ordonez, Carlos A. & Weathers, Duncan L.
Object Type:
Article
System:
The UNT Digital Library
Simulation Of An Antihydrogen Gravity Experiment Utilizing Multiple Apertures
The article presents an analytical model and a Monte Carlo simulation of an antihydrogen gravity experiment that would employ multiple apertures. The model was developed with the primary goal of reducing the experimental run time necessary to determine the direction of free fall acceleration for antimatter in the gravitational field of the Earth. The experiment would confine cryogenic antihydrogen plasma for producing antihydrogen (e.g., by three-body recombination).
Date:
April 19, 2013
Creator:
Hedlof, R. M. & Ordonez, Carlos A.
Object Type:
Article
System:
The UNT Digital Library
Electrostatic storage ring with focusing provided by the space charge of an electron plasma
Article describes an electronic storage ring that employs the space charge of an electron plasma for focusing. An advantage of the present concept is that slow ions, or even a stationary ion plasma, can be confined. The concept employs an artificially structured boundary, which is defined at present as one that produces a spatially periodic static field such that the spatial period and range of the field are much smaller than the dimensions of a plasma or charged-particle beam that is confined by the field.
Date:
April 19, 2013
Creator:
Pacheco, J. L.; Ordonez, Carlos A. & Weathers, Duncan L.
Object Type:
Article
System:
The UNT Digital Library
Accelerator-based fusion with a low temperature target
This article reports a study of a cold target with a high Fermi energy in light of recent research that points to a new phase of hydrogen, which is hypothesized to be related to metallic hydrogen. It has been shown that if the energy transfer between injected ions and target electrons is sufficiently small, net energy gain can be achieved. As such, the target is considered to be composed of nuclei and delocalized electrons.
Date:
April 19, 2013
Creator:
Phillips, R. E. & Ordonez, Carlos A.
Object Type:
Article
System:
The UNT Digital Library
Classical trajectory Monte Carlo code for simulating ion beam focusing or defocusing with magnetic elements modeled as current loops or current lines
Article describes a computational tool that can be used for designing magnetic focusing or defocusing systems. A fully three-dimensional classical trajectory Monte Carlo simulation has been developed.
Date:
April 19, 2013
Creator:
Lane, Ryan A. & Ordonez, Carlos A.
Object Type:
Article
System:
The UNT Digital Library
Dual levitated coils for antihydrogen production
Article on theoretical and experimental efforts to use dual levitated coils to confine relatively large, cold, dense non-drifting recombining antihydrogen plasmas. The theoretical effort includes the development of a classical trajectory Monte Carlo simulation of confinement. The experimental effort includes levitation of a NdFeB permanent ring magnet, which produces a magnetic field that is qualitatively similar to the field that would be produced by the two coaxial superconducting magnetic coils.
Date:
April 19, 2013
Creator:
Wofford, Joshua D. & Ordonez, Carlos A.
Object Type:
Article
System:
The UNT Digital Library
Antihydrogen Synthesis Via Magnetobound States of Protonium Within Proton-Positron-Antiproton Plasmas
Article studies the possibility that antihydrogen can be synthesized via three body recombination involving magnetobound protonium through classical trajectory simulation. It has been previously reported that proton antiproton collisions can result in a correlated drift of the particles perpendicular to a magnetic field. While the two particles are in their correlated drift, they are referred to as a magnetobound protonium system. Possible three body recombination resulting in bound state antihydrogen is studied when a magnetobound protonium system encounters a positron.
Date:
July 2016
Creator:
Hermosillo, M. & Ordonez, Carlos A.
Object Type:
Article
System:
The UNT Digital Library
Effect of a finite antiproton mass on antihydrogen synthesis via magnetobound positronium within electron-positron-antiproton plasmas
This article describes a study that was conducted to determine what would happen if a magnetobound positronium system encountered a finite-mass antiproton. The simulation incorporates a strong magnetic field (1 T) similar to that found within Penning traps. The simulation shows that with a finite-mass antiproton, the electron will be ejected from the system, and the positron is captured into a bound state with an antiproton thereby synthesizing antihydrogen.
Date:
July 2016
Creator:
Thornton, E. A. & Ordonez, Carlos A.
Object Type:
Article
System:
The UNT Digital Library
Magnetobound positronium and protonium
This article investigates the formation of magnetobound positronium and protonium via classical trajectory simulations of binary point charge interactions in an external magnetic field. The results of computer simulations of the fully three-dimensional trajectories of classical and non-relativistic point charges with the same mass, equal charge magnitude, and opposite sign are reported. The simulations show the formation of magnetobound positronium and protonium. The results yield formation cross sections, which are compared to analytical expressions. Additionally, the results reveal that magnetobound states drift across magnetic field lines.
Date:
August 27, 2014
Creator:
Correa, J. R. & Ordonez, Carlos A.
Object Type:
Article
System:
The UNT Digital Library
Phase space of positron trajectories exiting a charged particle source through a magnetic field point cusp
This article presents a configuration of magnetic fields using properties of cylindrically symmetric permanent magnets as a candidate to produce a high purity charged particle source or trap. Cylindrically symmetric hollow permanent magnets produce magnetic field point cusps on the axis of symmetry. A magnetic field point cusp reflects all particles that lie outside a narrow region of phase space, a region dependent on particle kinetic energies and on the magnetic field intensity.
Date:
December 30, 2013
Creator:
Kiester, A. S.; Pacheco, J. L.; Ordonez, Carlos A. & Weathers, Duncan L.
Object Type:
Article
System:
The UNT Digital Library
Giant cross-magnetic-field steps due to binary collisions between pair particles
Article explores giant cross-magnetic-field steps which occur as a result of positron-electron collisions. Within a constant magnetic field (e.g., 1 T), a collision between a positron and an electron can result in a correlated drift across the magnetic field for a continuous range of impact parameters. Within this range, drift distances orders of magnitude larger than that associated with like-charge collisions were observed by computer simulation.
Date:
March 5, 2015
Creator:
Aguirre, F. F. & Ordonez, Carlos A.
Object Type:
Article
System:
The UNT Digital Library
Measurements and Theoretical Predictions of Charge Exchange Cross Sections and Emission Spectra for O6+ with H2O, CO, CO2, CH4, N2, NO, N2O and Ar
Article reports absolute CE cross sections for up to three exchanges of the O6+ ion with electrons from the comet/planetary gases H2O, CO, CO2, CH4, N2, NO, N2O and Ar.
Date:
2015
Creator:
Machacek, J. R.; Mahapatra, Durga P.; Schultz, David R.; Ralchenko, Yu; Moradmand, A.; El Ghazaly, M. O. A. et al.
Object Type:
Article
System:
The UNT Digital Library
A New Way to Understand and Address Women’s Health in the Context of Complex Systems: Self-organizing Criticality
Article proposes applying concepts from nonlinear science developed and employed by physicists, economists, and meteorologists to women's health issues.
Date:
January 1, 2016
Creator:
Mancuso, Peggy; Liu, Fuqin; Restrepo, Elizabeth; Hamilton, Patricia; Grigolini, Paolo & Zou, Lin
Object Type:
Article
System:
The UNT Digital Library
Space-charge-based electrostatic plasma confinement involving relaxed plasma species
In this article, a numerical study is reported on the equilibrium properties of a surface-emitted or edge-confined non-drifting plasma. A self-consistent finite-differences evaluation of the electrostatic potential is carried out for a non-neutral plasma that follows a Boltzmann density distribution.
Date:
October 23, 2012
Creator:
Pacheco, J. L.; Ordonez, Carlos A. & Weathers, Duncan L.
Object Type:
Article
System:
The UNT Digital Library
Electrical Properties of Tin Selenide Under High-Pressure
The article investigates the pressure-induced phase transitions in tin selenide (SnSe). using the first-principles density functional calculations. The experimental results in the nanostructured SnSe revealed a phase transition at 4 GPa whereas that in the well-crystallized samples showed at 10 GPa.
Date:
November 3, 2016
Creator:
Ghosh, Angsula; Gusmão, M. S.; Chaudhuri, Puspitapallab; de Souza, S. Michielon; Mota, Cicero; Trichês, D. M. et al.
Object Type:
Article
System:
The UNT Digital Library
Pulsed cooperative backward emissions from non-degenerate atomic transitions in sodium
Article describes study which examines backward cooperative emissions from a dense sodium atomic vapor.
Date:
October 9, 2014
Creator:
Thompson, Jonathan V.; Ballmann, Charles W.; Cai, Han; Yi, Zhenhuan; Rostovtsev, Yuri V.; Sokolov, Alexei V. et al.
Object Type:
Article
System:
The UNT Digital Library
Spatially Periodic Electromagnetic Force Field For Plasma Confinement and Control
In this article, a theoretical understanding is developed of the single-particle reflection properties of a force field, considering the incident charged particles to have a non-drifting, isotropic velocity distribution. Classical trajectory Monte Carlo simulations and analytical modeling are employed. The initiation of an experimental effort to study force fields is described.
Date:
April 17, 2012
Creator:
Ordonez, Carlos A.; Pacheco, J. L. & Weathers, Duncan L.
Object Type:
Article
System:
The UNT Digital Library
Ionised outflows in z ~ 2.4 quasar host galaxies
This article presents a kinematical analysis of the [OIII]λ5007 emission line observed in six high-luminosity quasars at z ~ 2.4.
Date:
August 1, 2015
Creator:
Carniani, Stefano; Marconi, Alessandro; Maiolino, Roberto; Balmaverde, Barbara; Brusa, Marcella; Cano-Díaz, Mariana et al.
Object Type:
Article
System:
The UNT Digital Library
Electrical properties of SnSe under high-pressure
This article investigates the pressure-induced phase transitions in SnSe using the first-principles density functional calculations.
Date:
November 3, 2016
Creator:
Ghosh, Angsula; Gusmão, M. S.; Chaudhuri, Puspitapallab; de Souza, S. Michielon; Mota, Cicero; Trichês, D. M. et al.
Object Type:
Article
System:
The UNT Digital Library
Efficient multiband and broadband cross polarization converters based on slotted Lshaped nanoantennas
This article presents highly efficient reflective cross polarization converters based on metamaterials operating in the infrared regime.
Date:
November 14, 2014
Creator:
Ding, Jun; Arigong, Bayaner; Ren, Han; Zhou, Mi; Shao, Jin; Lin, Yuankun et al.
Object Type:
Article
System:
The UNT Digital Library
Direct Measurement of Group Delay Dispersion in Metamagnetics for Ultrafast Pulse Shaping
This article explores the use of magnetic resonant metamaterials, so called metamagnetics, as dispersive elements for optical pulse shaping.
Date:
September 24, 2012
Creator:
Brown, Dean P.; Walker, Mark A.; Urbas, Augustine M.; Kildishev, Alexander V.; Xiao, Shumin & Drachev, Vladimir P.
Object Type:
Article
System:
The UNT Digital Library
Optimization of nonlinear optical properties of ZnO micro and nanocrystals for biophotonics
This article investigates the defects in ZnO created during its synthesis and its affect on the second and third-order nonlinear processes.
Date:
July 21, 2011
Creator:
Urban, Ben E.; Lin, Jie; Kumar, Os; Senthilkumar, Kasilingam; Fujita, Yasuhisa & Neogi, Arup
Object Type:
Article
System:
The UNT Digital Library
Holographic fabrication of 3D photonic crystals through interference of multi-beams with 4 + 1, 5 + 1 and 6 + 1 configurations
This article fabricates 3D photonic crystals or quasi-crystals through single beam and single optical element based holographic lithography.
Date:
September 9, 2014
Creator:
George, David; Lutkenhaus, Jeffrey; Lowell, David; Moazzezi, Mojtaba; Adewole, Murthada; Philipose, Usha et al.
Object Type:
Article
System:
The UNT Digital Library