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Old Dominion University

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Articles 31 - 60 of 218

Full-Text Articles in Plasma and Beam Physics

A Proposed Beam-Beam Test Facility Combine, E. Nissen, Geoffrey Krafft, Jean Delayen Jan 2021

A Proposed Beam-Beam Test Facility Combine, E. Nissen, Geoffrey Krafft, Jean Delayen

Physics Faculty Publications

The COmpact Machine for Beam-beam Interactions in Non-Equilibrium systems (COMBINE) is a proposed, dedicated, beam-beam test facility. The base design would make use of a pair of identical octagonal rings (2.5 meters per side) one rotated 180 degrees from the other, meeting at their common interaction point. These would be fed by an electron gun producing up to 125 keV electrons. The low energy will allow for beam-beam tune shifts commensurate with existing colliders, some linac-ring type systems, and will also allow for an exploration of the predicted effects of gear-changing, which would be performed using a variable pathlength scheme. …

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Transient Behavior Of Drift And Ionization In Atmospheric Pressure Nitrogen Discharge, S. K. Dhali Jan 2021

Transient Behavior Of Drift And Ionization In Atmospheric Pressure Nitrogen Discharge, S. K. Dhali

Electrical & Computer Engineering Faculty Publications

The fluid models are frequently used to describe a non-thermal plasma such as a streamer discharge. The required electron transport data and rate coefficients for the fluid model are parametrized using the local field approximation (LFA) in first order models and the local-mean-energy approximation (LMEA) in second order models. We performed Monte Carlo simulations in Nitrogen gas with step changes in the E/N (reduced electric field) to study the behavior of the transport properties in the transient phase. During the transient phase of the simulation, we extract the instantaneous electron mean energy, which is different from the steady state mean …

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The Resistive Barrier Discharge: A Brief Review Of The Device And Its Biomedical Applications, Mounir Laroussi Jan 2021

The Resistive Barrier Discharge: A Brief Review Of The Device And Its Biomedical Applications, Mounir Laroussi

Electrical & Computer Engineering Faculty Publications

This paper reviews the principles behind the design and operation of the resistive barrier discharge, a low temperature plasma source that operates at atmospheric pressure. One of the advantages of this plasma source is that it can be operated using either DC or AC high voltages. Plasma generated by the resistive barrier discharge has been used to efficiently inactivate pathogenic microorganisms and to destroy cancer cells. These biomedical applications of low temperature plasma are of great interest because in recent times bacteria developed increased resistance to antibiotics and because present cancer therapies often are accompanied by serious side effects. Low …

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High Voltage Design And Evaluation Of Wien Filters For The Cebaf 200 Kev Injector Upgrade, Gabriel Palacios-Serrano, Helmut Baumgart, C. Hernández-García, P. Adderley, J. Benesch, D. Bullard, J. Grames, A. Hofler, D. Machie, M. Poelker, M. Stutzman, R. Suleiman Jan 2021

High Voltage Design And Evaluation Of Wien Filters For The Cebaf 200 Kev Injector Upgrade, Gabriel Palacios-Serrano, Helmut Baumgart, C. Hernández-García, P. Adderley, J. Benesch, D. Bullard, J. Grames, A. Hofler, D. Machie, M. Poelker, M. Stutzman, R. Suleiman

Electrical & Computer Engineering Faculty Publications

High-energy nuclear physics experiments at the Jefferson Lab Continuous Electron Beam Accelerator Facility (CEBAF) require highly spin-polarization electron beams, produced from strained super-lattice GaAs photocathodes, activated to negative electron affinity in a photogun operating at 130 kV dc. A pair of Wien filter spin rotators in the injector defines the orientation of the electron beam polarization at the end station target. An upgrade of the CEBAF injector to better support the upcoming MOLLER experiment requires increasing the electron beam energy to 200 keV, to reduce unwanted helicity correlated intensity and position systematics and provide precise control of the polarization orientation. …

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Evidence Of Increased Radio-Frequency Losses In Cavities From The Fundamental Power Coupler Cold Window, Frank Marhauser, Gianluigi Ciovati Jan 2021

Evidence Of Increased Radio-Frequency Losses In Cavities From The Fundamental Power Coupler Cold Window, Frank Marhauser, Gianluigi Ciovati

Physics Faculty Publications

High radio-frequency (rf) losses measured for cavities in original Continuous Electron Beam Accelerator Facility (CEBAF) cryomodules, compared to the losses measured in single-cavity tests, have been a long-standing issue related to their performance. We summarize experimental evidence of increased rf losses in CEBAF cavities arising from the fundamental power coupler cold window and waveguide, respectively. Cryogenic rf tests were done on cavities tested in vertical cryostats as well as inside cryomodules in the accelerator tunnel. The cold window metallization losses were assessed by combining numerical results with measured data obtained with an existing cryogenic waveguide resonator setup. The results showed …

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Beam Spin Asymmetry In Semi-Inclusive Electroproduction Of Hadron Pairs, M. J. Amaryan, M. Hattawy, S. E. Kuhn, Y. Prok, J. Zhang, Z. W. Zhao, Et Al., Clas Collaboration Jan 2021

Beam Spin Asymmetry In Semi-Inclusive Electroproduction Of Hadron Pairs, M. J. Amaryan, M. Hattawy, S. E. Kuhn, Y. Prok, J. Zhang, Z. W. Zhao, Et Al., Clas Collaboration

Physics Faculty Publications

A first measurement of the longitudinal beam spin asymmetry ALU in the semi-inclusive electroproduction of pairs of charged pions is reported. ALU is a higher-twist observable and offers the cleanest access to the nucleon twist-3 parton distribution function e(x). Data have been collected in the Hall-B at Jefferson Lab by impinging a 5.498-GeV electron beam on a liquid-hydrogen target, and reconstructing the scattered electron and the pion pair with the CLAS detector. One-dimensional projections of the AsinLUϕR moments are extracted for the kinematic variables of interest in the valence quark region. The …

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First Demonstration Of The Use Of Crab Cavities On Hadron Beams, R. Calaga, A. Alekou, F. Antoniou, R. B. Appleby, L. Arnaudon, K. Artoos, G. Arduini, V. Baglin, S. Barriere, H. Bartosik, P. Baudrenghien, I. Ben-Zvi, T. Bohl, A. Boucherie, O. S. Brüning, K. Brondzinski, A. Butterworth, G. Burt, O. Capatina, S. Calvo, T. Capelli, M. Carlà, F. Carra, L. R. Carver, A. Castilla-Loeza, E. Daly, L. Dassa, J. Delayen, S. U. De Silva, A. Dexter, M. Garlasche, F. Gerigk, L. Giordanino, D. Glenat, M. Guinchard, A. Harrison, E. Jensen, C. Julie, T. Jones, F. Killing, A. Krawczyk, T. Levens, R. Leuxe, B. Lindstrom, Z. Li, A. Macewen, A. Macpherson, P. Menendez, T. Mikkola, P. Minginette, J. Mitchell, E. Montesinos, G. Papotti, H. Park, C. Pasquino, S. Pattalwar, E. C. Pleite, T. Powers, B. Prochal, A. Ratti, L. Rossi, V. Rude, M. Therasse, R. Tomás, N. Stapely, I. Santillana, N. Shipman, J. Simonin, M. Sosin, J. Swieszek, N. Templeton, G. Vandoni, S. Verdú-Andrés, M. Wartak, C. Welsch, D. Wollman, Q. Wu, B. Xiao, E. Yamakawa, C. Zanoni, F. Zimmermann, A. Zwozniak Jan 2021

First Demonstration Of The Use Of Crab Cavities On Hadron Beams, R. Calaga, A. Alekou, F. Antoniou, R. B. Appleby, L. Arnaudon, K. Artoos, G. Arduini, V. Baglin, S. Barriere, H. Bartosik, P. Baudrenghien, I. Ben-Zvi, T. Bohl, A. Boucherie, O. S. Brüning, K. Brondzinski, A. Butterworth, G. Burt, O. Capatina, S. Calvo, T. Capelli, M. Carlà, F. Carra, L. R. Carver, A. Castilla-Loeza, E. Daly, L. Dassa, J. Delayen, S. U. De Silva, A. Dexter, M. Garlasche, F. Gerigk, L. Giordanino, D. Glenat, M. Guinchard, A. Harrison, E. Jensen, C. Julie, T. Jones, F. Killing, A. Krawczyk, T. Levens, R. Leuxe, B. Lindstrom, Z. Li, A. Macewen, A. Macpherson, P. Menendez, T. Mikkola, P. Minginette, J. Mitchell, E. Montesinos, G. Papotti, H. Park, C. Pasquino, S. Pattalwar, E. C. Pleite, T. Powers, B. Prochal, A. Ratti, L. Rossi, V. Rude, M. Therasse, R. Tomás, N. Stapely, I. Santillana, N. Shipman, J. Simonin, M. Sosin, J. Swieszek, N. Templeton, G. Vandoni, S. Verdú-Andrés, M. Wartak, C. Welsch, D. Wollman, Q. Wu, B. Xiao, E. Yamakawa, C. Zanoni, F. Zimmermann, A. Zwozniak

Physics Faculty Publications

Many future particle colliders require beam crabbing to recover geometric luminosity loss from the nonzero crossing angle at the interaction point (IP). A first demonstration experiment of crabbing with hadron beams was successfully carried out with high energy protons. This breakthrough result is fundamental to achieve the physics goals of the high luminosity LHC (HL-LHC) and the future circular collider (FCC). The expected peak luminosity gain (related to collision rate) is 65% for HL-LHC and even greater for the FCC. Novel beam physics experiments with proton beams in CERN’s Super Proton Synchrotron (SPS) were performed to demonstrate several critical aspects …

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Intense Monochromatic Photons Above 100 Kev From An Inverse Compton Source, Kirsten Deitrick, Georg H. Hoffstaetter, Carl Franck, Bruno D. Muratori, Peter H. Williams, Geoffrey A, Krafft, Balša Terzić, Joe Crone, Hywel Owen Jan 2021

Intense Monochromatic Photons Above 100 Kev From An Inverse Compton Source, Kirsten Deitrick, Georg H. Hoffstaetter, Carl Franck, Bruno D. Muratori, Peter H. Williams, Geoffrey A, Krafft, Balša Terzić, Joe Crone, Hywel Owen

Physics Faculty Publications

Quasimonochromatic x rays are difficult to produce above 100 keV, but have a number of uses in x-ray and nuclear science, particularly in the analysis of transuranic species. Inverse Compton scattering (ICS) is capable of fulfilling this need, producing photon beams with properties and energies well beyond the limits of typical synchrotron radiation facilities. We present the design and predicted output of such an ICS source at CBETA, a multiturn energy-recovery linac with a top energy of 150 MeV, which we anticipate producing x rays with energies above 400 keV and a collimated flux greater than 108 photons per second …

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The Concept And Applications Of A Dual Energy Storage Ring, Bhawin Dital, Andrew Hutton, Geoffrey Krafft, Fanglei Lin, Vasiliy Morozov, Yuhong Zhang Jan 2021

The Concept And Applications Of A Dual Energy Storage Ring, Bhawin Dital, Andrew Hutton, Geoffrey Krafft, Fanglei Lin, Vasiliy Morozov, Yuhong Zhang

Physics Faculty Publications

A dual energy electron storage ring configuration is initially proposed as an electron cooler to cool the ion beam in a collider. It consists of two energy loops, the electron beam in the high energy loop undergoes the synchrotron radiation damping to obtain the desired beam property and the beam in the low energy loop is for cooling of the ion beam. The two different energy loops are connected by an energy recovery linac. A lattice design of such a dual energy storage ring has been completed and beam stability conditions are established. We performed numerical simulations to demonstrate the …

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Characterizing Plasma With Emission Tomography-Feasibility Study On Synthetic And Experimental Data, M. Nikolić, A. Samolov, A. Godunov, L. Vušković,, S. Popović May 2020

Characterizing Plasma With Emission Tomography-Feasibility Study On Synthetic And Experimental Data, M. Nikolić, A. Samolov, A. Godunov, L. Vušković,, S. Popović

Physics Faculty Publications

We present a feasibility study on different tomographic algorithms to overcome the issues of finite sets of projection data, limited viewing angles, and noisy data, which cause the tomographic reconstruction to be an ill-posed inversion problem. We investigated three approaches: single angle Abel inversion, two angle approach, and multiple angle 2D plasma tomography. These methods were tested on symmetric and asymmetric sample functions and on experimental results from a supersonic flowing argon microwave plasma sustained in a cylindrical quartz cavity. The analysis focused on the afterglow region of the microwave flow where a plasmoid-like formation was observed. We investigated the …

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1d Fluid Model Of Rf-Excited Cold Atmospheric Plasmas In Helium With Air Gas Impurities, Yifan Liu, Dingxin Liu, Jishen Zhang, Bowen Sun, Aijun Yang, Michael G. Kong Apr 2020

1d Fluid Model Of Rf-Excited Cold Atmospheric Plasmas In Helium With Air Gas Impurities, Yifan Liu, Dingxin Liu, Jishen Zhang, Bowen Sun, Aijun Yang, Michael G. Kong

Bioelectrics Publications

Cold atmospheric plasmas (CAPs) in helium with air gas impurities (HeþAir for abbreviation) compromise the discharge stability of helium and the chemical reactivity of air, having great prospects for various applications such as plasma biomedicine. However, different kinds of reactive species are produced in HeþAir CAPs but only a few of them could be measured, and the plasma chemistry is so complex that the reported simulation models are simplified to a large extent, such as neglecting the space variation of CAPs by using a 0D model. As a result, much remains unknown for HeþAir CAPs, which hinders the development of …

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Interfacial Current Distribution Between Helium Plasma Jet And Water Solution, Sui Wang, Dingxin Liu, Zifeng Wang, Yifan Liu, Qiaosong Li, Xiaohua Wang, Michael G. Kong, Mingzhe Rong Jan 2020

Interfacial Current Distribution Between Helium Plasma Jet And Water Solution, Sui Wang, Dingxin Liu, Zifeng Wang, Yifan Liu, Qiaosong Li, Xiaohua Wang, Michael G. Kong, Mingzhe Rong

Bioelectrics Publications

The plasma-liquid interaction holds great importance for a number of emerging applications such as plasma biomedicine, yet a main fundamental question remains about the nature of the physiochemical processes occurring at the plasma-liquid interface. In this paper, the interfacial current distribution between helium plasma jet and water solution was measured for the first time by means of the splitting electrode method, which was borrowed from the field of arc plasma. For a plasma plume in continuous mode, it was found that the mean absolute current distribution at the plasma-liquid interface typically had an annular shape. This shape could be affected …

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Characterization Of Argon And Ar/Cl2 Plasmas Used For The Processing Of Niobium Superconducting Radio-Frequency Cavities, Jeremy J. Peshl Oct 2019

Characterization Of Argon And Ar/Cl2 Plasmas Used For The Processing Of Niobium Superconducting Radio-Frequency Cavities, Jeremy J. Peshl

Physics Theses & Dissertations

The plasma processing of superconducting radio-frequency (SRF) cavities has shown significant promise as a complementary or possible replacement for the current wet etch processes. Empirical relationships between the user-controlled external parameters and the effectiveness of Reactive Ion Etching (RIE) for the removal of surface layers of bulk niobium have been previously established. However, a lack of a physical description of the etching discharge, particularly as the external parameters are varied, limits the development of this technology. A full understanding of how these external parameters affect both the amount of material removed and the physical properties of the plasma would aid …

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Pulse Power Effects On Transient Plasma Ignition For Combustion, David Wayne Alderman Ii Oct 2019

Pulse Power Effects On Transient Plasma Ignition For Combustion, David Wayne Alderman Ii

Electrical & Computer Engineering Theses & Dissertations

Transient plasma ignition (TPI) uses highly non-equilibrium plasmas, driven by less than 100 nanosecond, high-voltage pulses, to initiate combustion. The effects of pulse repetition frequency (PRF) and ultrashort nanosecond rise times on TPI are investigated in this work using lean, stoichiometric, and rich air-fuel mixtures at atmospheric pressure. Experimental data show the transient plasmas driven by ultrashort rise time, high voltage pulses at high PRF’s enhance the combustion of lean or stoichiometric air-methane mixtures in a static chamber. In particular, increasing PRF enhances the combustion performance by means of reduced delay times independent of the equivalence ratio of the air-fuel …

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Effects Of Pulse Width On He Plasma Jets In Contact With Water Evaluated By Oh(A-X) Emission And Ohaq Production, Shutong Song, Esin B. Sözer, Chunqi Jiang Jun 2019

Effects Of Pulse Width On He Plasma Jets In Contact With Water Evaluated By Oh(A-X) Emission And Ohaq Production, Shutong Song, Esin B. Sözer, Chunqi Jiang

Bioelectrics Publications

Nanosecond pulsed helium plasma jets impinging on water produce hydroxyl radicals both in gas- and liquid-phase. In this study, the effects of pulse width on a repetitively pulsed plasma jet in contact with water are evaluated via OH(A-X) emission and OHaq production in water for various pulse widths ranging from 200 to 5000 ns. The maximal energy efficiency of OH(A-X) emission is obtained for pulse widths of 600-800 ns whereas the maximal efficiency of OHaq production is at 200 ns. Temporally-resolved emission spectroscopy shows that more than 40% of OH(A-X) emission is produced during the first 200 ns …

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The Effect Of Tube Geometry On The Chiral Plasma, S. Jin, D. Zou, X. Lu, Mounir Laroussi Jan 2019

The Effect Of Tube Geometry On The Chiral Plasma, S. Jin, D. Zou, X. Lu, Mounir Laroussi

Electrical & Computer Engineering Faculty Publications

A chiral plasma plume has recently been reported inside a circular quartz tube without the use of an external magnetic field. It is believed that the quartz tube plays an important role in the formation of the chiral plasma plume. In this paper, to better understand how this interesting structure is generated, the effect of the tube geometry on the chiral plasma is investigated. First, the effect of the thickness of the tube wall on the chiral plasma is investigated. It is interesting to find that a too thin or too thick tube wall is not favorable for generating the …

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Measurement Of The Beam Spin Asymmetry Of →Ep → E'P'Η In The Deep-Inelastic Regime With Clas, B. Zhao, A. Kim, K. Joo, I . Bedlinskiy, W. Kim, V. Kubarovsky, M. Ungaro, G. Gavalian, A. Klein, S. E. Kuhn, Clas Collaboration Jan 2019

Measurement Of The Beam Spin Asymmetry Of →Ep → E'P'Η In The Deep-Inelastic Regime With Clas, B. Zhao, A. Kim, K. Joo, I . Bedlinskiy, W. Kim, V. Kubarovsky, M. Ungaro, G. Gavalian, A. Klein, S. E. Kuhn, Clas Collaboration

Physics Faculty Publications

The beam spin asymmetry of the exclusive pseudoscalar channel →ep→e′p′η was measured for the first time in the deep-inelastic regime (W > 2 GeV/c2 and Q2 > 1 GeV2 /c2) using a longitudinally polarized 5.78 GeV electron beam at Jefferson Lab with the CEBAF Large Acceptance Spectrometer. The data were accumulated in 144 four-dimensional bins of Q2, xB, −t and ϕ over a wide kinematic range, where ϕ is the azimuthal angle between the lepton and hadron scattering planes, The measured azimuthal dependence with large amplitudes of the sin ϕ moments is …

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Carbon Multicharged Ion Generation From Laser-Spark Ion Source, Md. Mahmudur Rahman, Oguzhan Balki, Hani E. Elsayed-Ali Jan 2019

Carbon Multicharged Ion Generation From Laser-Spark Ion Source, Md. Mahmudur Rahman, Oguzhan Balki, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Multicharged carbon ions are generated by using a laser-assisted spark-discharge ion source. A Q-switched Nd:YAG laser pulse (1064 nm, 7 ns, ≤ 4.5 × 109 W/cm2) focused onto the surface of a glassy carbon target results in its ablation. The spark-discharge (∼1.2 J energy, ∼1 µs duration) is initiated along the direction of the plume propagation between the target surface and a grounded mesh that is parallel to the target surface. Ions emitted from the laser-spark plasma are detected by their time-of-flight using a Faraday cup. The ion energy-to-charge ratio is analyzed by a three-mesh retarding field …

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Compact -300 Kv Dc Inverted Insulator Photogun With Biased Anode And Alkali-Antimonide Photocathode, C. Hernandez-Garcia, P. Adderley, B. Bullard, J. Benesch, J. Grames, J. Gubeli, F. Hannon, J. Hansknecht, J. Jordan, R. Kazimi, G. A. Krafft, M. A. Mamun, M. Poelker, M. L. Stutzman, R. Suleiman, M. Tiefenback, Y. Wang, S. Zhang, H. Baumgart, G. Palacios-Serrano, S. Wijethunga, J. Yoskowitz, C. A. Valerio Lizarraga, R. Montoya Soto, A. Canales Ramos Jan 2019

Compact -300 Kv Dc Inverted Insulator Photogun With Biased Anode And Alkali-Antimonide Photocathode, C. Hernandez-Garcia, P. Adderley, B. Bullard, J. Benesch, J. Grames, J. Gubeli, F. Hannon, J. Hansknecht, J. Jordan, R. Kazimi, G. A. Krafft, M. A. Mamun, M. Poelker, M. L. Stutzman, R. Suleiman, M. Tiefenback, Y. Wang, S. Zhang, H. Baumgart, G. Palacios-Serrano, S. Wijethunga, J. Yoskowitz, C. A. Valerio Lizarraga, R. Montoya Soto, A. Canales Ramos

Electrical & Computer Engineering Faculty Publications

This contribution describes the latest milestones of a multiyear program to build and operate a compact −300  kV dc high voltage photogun with inverted insulator geometry and alkali-antimonide photocathodes. Photocathode thermal emittance measurements and quantum efficiency charge lifetime measurements at average current up to 4.5 mA are presented, as well as an innovative implementation of ion generation and tracking simulations to explain the benefits of a biased anode to repel beam line ions from the anode-cathode gap, to dramatically improve the operating lifetime of the photogun and eliminate the occurrence of micro-arc discharges.

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Ignition Of A Plasma Discharge Inside An Electrodeless Chamber: Methods And Characteristics, Mounir Laroussi Jan 2019

Ignition Of A Plasma Discharge Inside An Electrodeless Chamber: Methods And Characteristics, Mounir Laroussi

Electrical & Computer Engineering Faculty Publications

In this paper the generation and diagnostics of a reduced pressure (300 mTorr to 3 Torr) plasma generated inside an electrodeless containment vessel/chamber are presented. The plasma is ignited by a guided ionization wave emitted by a low temperature pulsed plasma jet. The diagnostics techniques include Intensified Charge Coupled Device (ICCD) imaging, emission spectroscopy, and Langmuir probe. The reduced-pressure discharge parameters measured are the magnitude of the electric field, the plasma electron number density and temperature, and discharge expansion speed.

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Polarization Analysis Of P̄ Produced In Pa Collisions, D. Grzonka, D. Alfs, A. Asaturyan, M. Carmignotto, M. Diermaier, W. Eyrich, B. Glowacz, F. Hauenstein, T. Horn, K. Kilian Jan 2019

Polarization Analysis Of P̄ Produced In Pa Collisions, D. Grzonka, D. Alfs, A. Asaturyan, M. Carmignotto, M. Diermaier, W. Eyrich, B. Glowacz, F. Hauenstein, T. Horn, K. Kilian

Physics Faculty Publications

A quite simple procedure for the generation of a polarized antiproton beam could be worked out if antiprotons are produced with some polarization. In order to investigate this possibility measurements of the polarization of produced antiprotons have been started at a CERN/PS test beam. The polarization will be determined from the asymmetry of the elastic antiproton scattering at a liquid hydrogen target in the CNI region for which the analyzing power is well known. The data are under analysis and an additional measurement is done in 2018. Details on the experiment and the ongoing data analysis will be given.

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Exploring The Structure Of The Bound Proton With Deeply Virtual Compton Scattering, M. Hattawy, N. A. Baltzell, R. Dupré, S. Bültmann, B. Torayev, G. Gavalian, F. Hauenstein, S. E. Kuhn, M. Khachatryan, M. Mayer, J. Poudel, Y. Prok, L. B. Weinstein, J. Zhang, Z. W. Zhao, Clas Collaboration Jan 2019

Exploring The Structure Of The Bound Proton With Deeply Virtual Compton Scattering, M. Hattawy, N. A. Baltzell, R. Dupré, S. Bültmann, B. Torayev, G. Gavalian, F. Hauenstein, S. E. Kuhn, M. Khachatryan, M. Mayer, J. Poudel, Y. Prok, L. B. Weinstein, J. Zhang, Z. W. Zhao, Clas Collaboration

Physics Faculty Publications

In the past two decades, deeply virtual Compton scattering of electrons has been successfully used to advance our knowledge of the partonic structure of the free proton and investigate correlations between the transverse position and the longitudinal momentum of quarks inside the nucleon. Meanwhile, the structure of bound nucleons in nuclei has been studied in inclusive deep-inelastic lepton scattering experiments off nuclear targets, showing a significant difference in longitudinal momentum distribution of quarks inside the bound nucleon, known as the EMC effect. In this Letter, we report the first beam spin asymmetry (BSA) measurement of exclusive deeply virtual Compton scattering …

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Spectroscopy Of Neon For The Advanced Undergraduate Laboratory, H. C. Busch, M. B. Cooper, C. I. Sukenik Jan 2019

Spectroscopy Of Neon For The Advanced Undergraduate Laboratory, H. C. Busch, M. B. Cooper, C. I. Sukenik

Physics Faculty Publications

We describe a spectroscopy experiment, suitable for upper-division laboratory courses, that investigates saturated absorption spectroscopy and polarization spectroscopy in a neon discharge. Both experiments use nearly identical components, allowing students to explore both techniques in a single apparatus. Furthermore, because the wavelength of the laser is in the visible part of the spectrum (640 nm), the experiment is well-suited for students with limited experience in optical alignment. The labs nicely complement a course in atomic or plasma physics, provide students with the opportunity to gain important technical skills in the area of optics and lasers, and can provide an introduction …

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Drift Chamber Calibration And Particle Identification In The P-349 Experiment, D. Alfs, A. Asaturyan, M. Carmignotto, M. Diermaier, W. Eyrich, B. Glowacz, D. Grzonka, Florian Hauenstein, T. Horn, K. Kilian, D. Lersch, S. Malbrunot-Ettenauer, A. Mkrtchyan, H. Mkrtchyan, P. Moskal, P. Nadel-Turonski, W. Oelert, J. Ritman, T. Sefzick, V. Tadevosyan, E. Widmann, M. Wolke, S. Zhamkochyan, M. Zieliński, A. Zink, J. Zmeskal Jan 2019

Drift Chamber Calibration And Particle Identification In The P-349 Experiment, D. Alfs, A. Asaturyan, M. Carmignotto, M. Diermaier, W. Eyrich, B. Glowacz, D. Grzonka, Florian Hauenstein, T. Horn, K. Kilian, D. Lersch, S. Malbrunot-Ettenauer, A. Mkrtchyan, H. Mkrtchyan, P. Moskal, P. Nadel-Turonski, W. Oelert, J. Ritman, T. Sefzick, V. Tadevosyan, E. Widmann, M. Wolke, S. Zhamkochyan, M. Zieliński, A. Zink, J. Zmeskal

Physics Faculty Publications

The goal of the P-349 experiment is to test whether 3.5 GeV/c antiprotons produced in high-energy proton-proton collisions are polarized in view of the preparation of a polarized antiproton beam. In this article, we present the details of the ongoing analysis focused on the drift chambers calibration and particle identification with DIRC.

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Argon Metastable And Resonant Level Densities In Ar And Ar/Cl² Discharges Used For The Processing Of Bulk Niobium, Jeremy Peshl, Roderick Mcneill, Charles I. Sukenik, Milka Nikolić, Svetozar Popović, Leposava Vŭsković Jan 2019

Argon Metastable And Resonant Level Densities In Ar And Ar/Cl² Discharges Used For The Processing Of Bulk Niobium, Jeremy Peshl, Roderick Mcneill, Charles I. Sukenik, Milka Nikolić, Svetozar Popović, Leposava Vŭsković

Physics Faculty Publications

A comparative analysis of two popular spectroscopy techniques is conducted in a coaxial cylindrical capacitively coupled discharge designed for the plasma processing of superconducting radio frequency (SRF) cavities. The density of the metastable and resonant levels in Ar is measured in both Ar and Ar/Cl2 discharges to properly characterize the unique discharge system and aid in the development of a cavity etching routine. The first method, deemed the “branching fraction method,” utilizes the sensitivity of photon reabsorption of radiative decay to measure the lower state (metastable and resonant) densities by taking ratios of spectral lines with a common upper …

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Determination Of The Magnetic Field Dependence Of The Surface Resistance Of Superconductors From Cavity Tests, J. R. Delayen, H. Park, S. Su. De Silva, G. Ciovati, Z. Li Dec 2018

Determination Of The Magnetic Field Dependence Of The Surface Resistance Of Superconductors From Cavity Tests, J. R. Delayen, H. Park, S. Su. De Silva, G. Ciovati, Z. Li

Physics Faculty Publications

We present a general method to derive the magnetic field dependence of the surface resistance of superconductors from the Q-curves obtained during the cryogenic tests of cavities. The results are applied to coaxial half-wave cavities, TM-like “elliptical” accelerating cavities, and cavities of more complicated geometries.

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Investigation On The Rons And Bactericidal Effects Induced By He + O2 Cold Plasma Jets: In Open Air And In An Airtight Chamber, Han Xu, Dingxin Liu, Weitao Wang, Zhijie Liu, Li Guo, Mingzhe Rong, Michael G. Kong Nov 2018

Investigation On The Rons And Bactericidal Effects Induced By He + O2 Cold Plasma Jets: In Open Air And In An Airtight Chamber, Han Xu, Dingxin Liu, Weitao Wang, Zhijie Liu, Li Guo, Mingzhe Rong, Michael G. Kong

Bioelectrics Publications

He + O2 plasma jets in open air and in an airtight chamber are comparatively studied, with respect to their production of gaseous/aqueous reactive species and their antibacterial effects. Under the same discharge power, the plasma jet in open air has higher densities of gaseous reactive species and a higher concentration of aqueous H2O2 but lower concentrations of aqueous OH and O2-. In addition, the increase in the O2 ratio in He in both plasma jets causes a linear decrease in the population of gaseous reactive species, except for O(3p5P) …

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High-Brilliance, High-Flux Compact Inverse Compton Light Source, K. E. Deitrick, G. A. Krafft, B. Terzić, J. R. Delayen Aug 2018

High-Brilliance, High-Flux Compact Inverse Compton Light Source, K. E. Deitrick, G. A. Krafft, B. Terzić, J. R. Delayen

Physics Faculty Publications

The Old Dominion University Compact Light Source (ODU CLS) design concept is presented-a compact Inverse Compton Light Source (ICLS) with flux and brilliance orders of magnitude beyond conventional laboratory-scale sources and greater than other compact ICLS designs. This concept utilizes the physics of inverse Compton scattering of an extremely low emittance electron beam by a laser pulse of rms length of approximately two-thirds of a picosecond (2/3 ps). The accelerator is composed of a superconducting radio frequency (SRF) reentrant gun followed by four double-spoke SRF cavities. After the linac are three quadrupole magnets to focus the electron beam to the …

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Generation Of Large-Volume Diffuse Plasma By An External Ionization Wave From A Single-Electrode Plasma Jet, Seyed Hamid Razavi Barzoki Jul 2018

Generation Of Large-Volume Diffuse Plasma By An External Ionization Wave From A Single-Electrode Plasma Jet, Seyed Hamid Razavi Barzoki

Electrical & Computer Engineering Theses & Dissertations

A non-thermal transient diffuse plasma can be generated remotely in a nonconductive reduced pressure chamber by an external guided fast ionization wave (FIW). We found that an atmospheric-pressure low-temperature plasma jet (APPJ) can be a source of FIW which transfers an enhanced electric field at the wave front across a reduced pressure Pyrex glass chamber with no electrical connection to the chamber. Here, we studied the formation and propagation of the APPJ plasma, the interaction of atmospheric-pressure guided FIW with a dielectric surface which forms the wall of the reduced-pressure system, and the formation and propagation of the reduce-pressure FIW …

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Comparison Between The Water Activation Effects By Pulsed And Sinusoidal Helium Plasma Jets, Han Xu, Dingxin Liu, Wenjie Xia, Chen Chen, Weitao Wang, Zhijie Liu, Xiaohua Wang, Michael G. Kong Jan 2018

Comparison Between The Water Activation Effects By Pulsed And Sinusoidal Helium Plasma Jets, Han Xu, Dingxin Liu, Wenjie Xia, Chen Chen, Weitao Wang, Zhijie Liu, Xiaohua Wang, Michael G. Kong

Bioelectrics Publications

Comparisons between pulsed and sinusoidal plasma jets have been extensively reported for the discharge characteristics and gaseous reactive species, but rarely for the aqueous reactive species in water solutions treated by the two types of plasma jets. This motivates us to compare the concentrations of aqueous reactive species induced by a pulsed and a sinusoidal plasma jet, since it is widely reported that these aqueous reactive species play a crucial role in various plasma biomedical applications. Experimental results show that the aqueous H2O2, OH/O2−, and O2−/ONOO− induced by the …

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