UNT College of Arts and Sciences - 162 Matching Results

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Confinement of antiprotons in the electrostatic space charge of positrons in a model of the ALPHA antihydrogen trap

Description: 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.
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Artificially Structured Boundary for a high purity ion trap or ion source

Description: 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 ass… more
Date: August 1, 2014
Creator: Pacheco, J. L.; Ordonez, Carlos A. & Weathers, Duncan L.
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open access

Simulation Of An Antihydrogen Gravity Experiment Utilizing Multiple Apertures

Description: 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.
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open access

Electrostatic storage ring with focusing provided by the space charge of an electron plasma

Description: 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 … more
Date: April 19, 2013
Creator: Pacheco, J. L.; Ordonez, Carlos A. & Weathers, Duncan L.
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open access

Accelerator-based fusion with a low temperature target

Description: 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.
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open access

Dual levitated coils for antihydrogen production

Description: 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 co… more
Date: April 19, 2013
Creator: Wofford, Joshua D. & Ordonez, Carlos A.
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open access

Antihydrogen Synthesis Via Magnetobound States of Protonium Within Proton-Positron-Antiproton Plasmas

Description: 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 anti… more
Date: July 2016
Creator: Hermosillo, M. & Ordonez, Carlos A.
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open access

Effect of a finite antiproton mass on antihydrogen synthesis via magnetobound positronium within electron-positron-antiproton plasmas

Description: 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.
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open access

Magnetobound positronium and protonium

Description: 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 cro… more
Date: August 27, 2014
Creator: Correa, J. R. & Ordonez, Carlos A.
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open access

Phase space of positron trajectories exiting a charged particle source through a magnetic field point cusp

Description: 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: August 1, 2014
Creator: Kiester, A. S.; Pacheco, J. L.; Ordonez, Carlos A. & Weathers, Duncan L.
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open access

Giant cross-magnetic-field steps due to binary collisions between pair particles

Description: 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.
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open access

Measurements and Theoretical Predictions of Charge Exchange Cross Sections and Emission Spectra for O6+ with H2O, CO, CO2, CH4, N2, NO, N2O and Ar

Description: 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.
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open access

Space-charge-based electrostatic plasma confinement involving relaxed plasma species

Description: 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.
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open access

Electrical Properties of Tin Selenide Under High-Pressure

Description: 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.
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open access

Spatially Periodic Electromagnetic Force Field For Plasma Confinement and Control

Description: 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.
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