Digital Commons Network^™

On The Chronological Understanding Of The Homogeneous Dielectric Barrier Discharge, Xinpei Lu, Zhi Fang, Dong Dai, Tao Shao, Feng Liu, Cheng Zhang, Dawei Liu, Lanlan Nie, Chunqi Jiang

Bioelectrics Publications

Dielectric barrier discharges (DBD) are widely utilised non-equilibrium atmospheric pressure plasmas with a diverse range of applications, such as material processing, surface treatment, light sources, pollution control, and medicine. Over the course of several decades, extensive research has been dedicated to the generation of homogeneous DBD (H-DBD), focussing on understanding the transition from H-DBD to filamentary DBD and exploring strategies to create and sustain H-DBD. This paper first discusses the influence of various parameters on DBD, including gas flow, dielectric material, surface conductivity, and mesh electrode. Secondly, a chronological literature review is presented, highlighting the development of H-DBD and the …

Paschen-Line Constraints On Dust Attenuation And Star Formation At Z ∼ 1–3 With Jwst/ Nirspec, Naveen Reddy, Michael W. Topping, Ryan L. Sanders, Alice E. Shapley, Gabriel B. Brammer

Physics and Astronomy Faculty Publications

We use medium-resolution JWST/NIRSpec observations from the Cosmic Evolution Early Release Science Survey to place the first constraints on dust attenuation and star formation based on Paschen lines for a sizable sample of 63 galaxies at redshifts z = 1.0-3.1. Our analysis indicates strong correlations between the Balmer decrement, Hα/Hβ, and line ratios that include Paschen lines (i.e., Paα/Hβ, Paβ/Hβ, and the Paschen decrement, Paα/Paβ), suggesting that the former is sensitive to the overall dust obscuration toward H ii regions in high-redshift galaxies. The line ratios are used to derive nebular reddening, E(B − V)_neb, and star formation …

Detecting High-Lying Rydberg States Using Two-Step Electromagnetically Induced Transparency And Frequency Modulation Spectroscopy Techniques, Kate Jensen

Honors Theses

Resonant optical excitation of high-lying Rydberg states in room temperature 85Rb was investigated using light from two homemade external cavity diode lasers (ECDL). This was done using a ladder schema of the Electromagnetically Induced Transparency (EIT) technique. The approximate EIT wavelengths used were 780 nm (the probe beam) to provide step-wise excitation of valence rubidium electrons from the 5S1/2 → 5P3/2 tran- sition, and then 482 nm (the coupling beam) to excite from the 5P3/2 state to a high-lying Rydberg nD state with an orbital angular momentum = 2. Successful excitation of the Rydberg states was observed using Frequency Modulation …

Novel Quantum Materials For Spintronic And Opto-Electronic Applications, Ali Sarikhani

Doctoral Dissertations

"Multi-functional quantum materials play a crucial role in the development of spintronics and opto-electronics, as their properties can greatly influence device performance. For instance, in spintronics, materials such as ferromagnetic half-metals, Giant Magnetoresistants (GMR), and magnetic semiconductors have been extensively studied due to their ability to manipulate the spin of electrons for applications in magnetic storage. In opto-electronics, materials such as Diluted Magnetic Semiconductors (DMS) and non-oxide Transparent Conductors (TC) offer advantages such as tunable bandgap and high absorption coefficients, which enable improved device performance.

For this purpose, we have experimentally investigated the compounds that have shown theoretically interesting physical …

Near-Ir Spectroscopic Analysis Of The Primary Volatile Composition Of Long And Short-Period Comets, Younas Khan

Doctoral Dissertations

"Comets are among the most well-preserved objects that formed in the protosolar nebula ∼4.5 Gyr ago. Hence, they are important for understanding various aspects of the formation, evolution, and habitability of the solar system. Multiple primary volatiles (molecules directly sublimating into the coma from the nucleus) emit via rovibrational transitions in the near-IR, providing opportunities to calculate their abundances. To date, only ∼50 comets have been characterized for their primary volatiles, with the short-period Jupiter-family comets (JFCs) being significantly underrepresented. In contrast, hundreds of comets have been sampled at optical/UV wavelengths, primarily for the composition of daughter species, leading to …

Detailed Analysis Of The Tev Γ-Ray Sources 3hwc J1928+178, 3hwc J1930+188, And The New Source Hawc J1932+192, A. Albert, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A.Ayala Solares, R. Babu, D. Huang, P. Hüntemeyer, R. Turner, X. Wang, Et Al.

Michigan Tech Publications, Part 1

The latest High Altitude Water Cherenkov (HAWC) point-like source catalog up to 56 TeV reported the detection of two sources in the region of the Galactic plane at galactic longitude 52° < ℓ < 55°, 3HWC J1930+188 and 3HWC J1928+178. The first one is associated with a known TeV source, the supernova remnant SNR G054.1+00.3. It was discovered by one of the currently operating Imaging Atmospheric Cherenkov Telescope (IACT), the Very Energetic Radiation Imaging Telescope Array System (VERITAS), detected by the High Energy Stereoscopic System (H.E.S.S), and identified as a composite SNR. However, the source 3HWC J1928+178, discovered by HAWC and coincident with the pulsar PSR J1928+1746, was not detected by any IACT despite their long exposure on the region, until a recent new analysis of H.E.S.S. data was able to confirm it. Moreover, no X-ray counterpart has been detected from this pulsar. We present a multicomponent fit of this region using the latest HAWC data. This reveals an additional new source, HAWC J1932+192, which is potentially associated with the pulsar PSR J1932+1916, whose γ-ray emission could come from the acceleration of particles in its pulsar wind nebula. In the case of 3HWC J1928+178, several possible explanations are explored, in an attempt to unveil the origins of the very-high-energy γ-ray emission.

Efficient Text Bounding Box Identification Using Mask R-Cnn: Case Of Thai Documents, Phanthakan Kiatphaisansophon

Chulalongkorn University Theses and Dissertations (Chula ETD)

Text detection is a fundamental task in computer vision, particularly for Optical Character Recognition (OCR) application. This research focuses on text detection part of the OCR. Our previous text detection model, CRAFT (Character-Region Awareness For Text detection) has shown promising outcomes in bounding box identification. Nevertheless, it encounters issues associated with post-processing and multiline text. The post-processing related to the necessity to reconfigure the model when new documents are introduced, resulting in inefficiencies and complexities. Also the CRAFT model tends to blend bounding boxes from consecutive lines, introducing errors and impacting the accuracy in the text recognition part of the …

Development Of Spintronic Materials By Stoichiometric Engineering Of Cofeval, Gavin Baker, Matthew Wieberdink, Jax Wysong

The Journal of Undergraduate Research

We have carried out an experimental investigation of the Heusler Alloy CoFeVAl and its two variants Co_1.5Fe_0.5VAl and CoFeVAl_0.5Si_0.5 for their potential application in the field of spintronics. Heusler alloys are investigated for their many remarkable properties, including half-metallicity and spin-gapless semi-conductivity. Spintronic technology utilizes the intrinsic spin of an electron for information storage and manipulation in solid state devices. We synthesized these alloys using arc-melting and annealing. All three alloys were found to have cubic crystal structures with varying disorders. The parent alloy CoFeVAl shows a magnetic transition at 65 K. However, …

Computational Modeling, Simulation, And Potential Applications Of Optical Stochastic Cooling, Austin J. Dick

Graduate Research Theses & Dissertations

With the rising demand for intense particles beams, much research is being conducted in the area of particle beam cooling. One of these methods, called Stochastic Cooling (SC) (developed at CERN in the 1970's), delivered a feedback method to improve the quality and lifetime of circulating proton beams by reducing their 6D phase-space and has been widely implemented in a number of hadron machines. However, traditional stochastic cooling schemes are limited by the bandwidth of microwave frequency systems. Optical Stochastic Cooling (OSC) is a promising extension of the stochastic cooling beam cooling technique. OSC instead uses optical wavelengths which allows …

The Mceliece Cryptosystem As A Solution To The Post-Quantum Cryptographic Problem, Isaac Hanna

Senior Honors Theses

The ability to communicate securely across the internet is owing to the security of the RSA cryptosystem, among others. This cryptosystem relies on the difficulty of integer factorization to provide secure communication. Peter Shor’s quantum integer factorization algorithm threatens to upend this. A special case of the hidden subgroup problem, the algorithm provides an exponential speedup in the integer factorization problem, destroying RSA’s security. Robert McEliece’s cryptosystem has been proposed as an alternative. Based upon binary Goppa codes instead of integer factorization, his cryptosystem uses code scrambling and error introduction to hinder decrypting a message without the private key. This …

Study Of The Dynamics Of Glasses Using Nuclear Resonance Time Domain Interferometry, Marc Pavlik

Graduate Research Theses & Dissertations

Nuclear resonance time domain interferometry (NR-TDI) is used to study the slow dy- namics of liquids (that do not require M ̈ossbauer isotopes) at atomic and molecular length scales between 1 A to 10 nm and at time scales between 1 ns to 10 μs. This new spectroscopy technique covers a new range of previously unexplored momentum transfers between 1 to 100 nm−1 and energies between 10 peV to 100 neV allowing an investigation into the dynami- cal motion of molecules, liquids, and glasses. The notoriously low count rate from quasielastic scattering experiments makes measurements difficult when using synchrotron x-rays …

Can The Xy+Z Heisenberg Model Be Compressed Using The Yang-Baxter Equation? An Exploration Of The Compression Of Quantum Time Dynamic Circuits Describing Heisenberg Spin Chains, Miriam Caron, Bo Peng Dr., Scott Gould Dr., Kevin Setter Dr., Niranjan Govind Dr.

Pitzer Senior Theses

Quantum computing is currently deployed on noisy intermediate-scale quantum (NISQ) devices, which are only able to simulate circuits reliably on shallow depth quantum circuits. A promising problem on near-term quantum computers is quantum time dynamics (QTD). However, QTD circuits grow with increasing time simulations making them difficult to simulate on NISQ devices. This thesis project explores QTD simulations in variations of 1D Heisenberg spin chains with nearest-neighbor and transverse external field interactions with an eye towards studying the dynamics in broader classes of spin models. I first study the quantum Yang-Baxter equation (YBE) and how it has been shown to …

The Gas And Stellar Content Of A Metal-Poor Galaxy At Z = 8.496 As Revealed By Jwst And Alma, K. E. Heintz, C. Giménez-Arteaga, S. Fujimoto, Gabriel B. Brammer, D. Espada, S. Gillman, J. González-López, T. R. Greve, Yuichi Harikane, B. Hatsukade, K. K. Knudsen, Anton M. Koekemoer, K. Kohno, V. Kokorev, M. M. Lee, Georgios E. Magdis, E. J. Nelson, F. Rizzo, Ryan L. Sanders, D. Schaerer, Alice E. Shapley, V. B. Strait, S. Toft, F. Valentino, A. Van Der Wel, A. P. Vijayan, D. Watson, F. E. Bauer, Amber Christiansen, C. R. Christiansen, S. N. Wilson

Physics and Astronomy Faculty Publications

We present a joint analysis of the galaxy S04590 at z = 8.496 based on NIRSpec, NIRCam, and NIRISS observations obtained as part of the Early Release Observations program of the James Webb Space Telescope (JWST) and the far-infrared [C ii] 158 μm emission line detected by dedicated Atacama Large Millimeter/submillimeter Array (ALMA) observations. We determine the physical properties of S04590 from modeling of the spectral energy distribution (SED) and through the redshifted optical nebular emission lines detected with JWST/NIRSpec. The best-fit SED model reveals a low-mass (M _⋆ = 10^7.2-10⁸ M _⊙) galaxy with a …

Interfacial And Surface Magnetism In Epitaxial Nico2o4(001)/Mgal2o4 Films, Corbyn Mellinger, Xiao Wang, Arjun Subedi, Andy T. Clark, Takashi Komesu, Richard Rosenberg, Peter A. Dowben, Xuemei Cheng, Xiaoshan Xu

Physics Faculty Research and Scholarship

NiCo2O4 (NCO) films grown on MgAl2O4 (001) substrates have been studied using magnetometry, x-ray magnetic circular dichroism (XMCD) based on x-ray absorption spectroscopy, and spin-polarized inverse photoemission spectroscopy (SPIPES) with various thickness down to 1.6 nm. The magnetic behavior can be understood in terms of a layer of optimal NCO and an interfacial layer (1.2± 0.1 nm), with a small canting of magnetization at the surface. The thickness dependence of the optimal layer can be described by the finite-scaling theory with a critical exponent consistent with the high perpendicular magnetic anisotropy. The interfacial layer couples antiferromagnetically to the optimal layer, …

Second-Harmonic Signature Of Chiral Spin Structures In W/Pt/Co Heterostructures With Tunable Magnetic Anisotropy, Yang Wang, Ying-Ting Chan, Xiao Wang, Tao Wang, Xuemei Cheng, Weida Wu, John Q. Xiao

Physics Faculty Research and Scholarship

Second-harmonic Hall voltage (SHV) measurement method has been widely used to characterize the strengths of spin–orbit torques (SOTs) in heavy metal/ferromagnet thin films saturated in the single-domain regime. Here, we show that the magnetic anisotropy of a W/Pt/Co trilayer can be robustly tuned from in-plane to out-of-plane by varying W, Pt, or Co thicknesses. Moreover, in samples with easy-cone anisotropy, SHV measurements exhibit anomalous ‘humps’ in the multidomain regime accessed by applying a nearly out-of-plane external magnetic field. These hump features can only be explained as a result of the formation of Néel-type domain walls, efficiently driven by nevertheless small …

Diethoxycarbonyl-Bodipys As Heavy-Atom-Free Photosensitizers For Holographic Recording In Cellulose Acetate Photopolymer, Aimee Sheehan, Tatsiana Mikulchyk, Catherine S.P. De Castro, Safakath Karuthedath, Wejdan Althobaiti, Metodej Dvoracek, Sabad-E Gul, Hugh Byrne, FréDéRic Laquai, Izabela Naydenova, Mikhail Filatov

Articles

A series of new heavy-atom-free photosensitizers based on 2,6-diethoxycarbonyl-BODIPY scaffold was designed and applied for holographic recording in a photopolymerizable material. Photoinduced electron transfer between the BODIPY and meso-aryl subunits, followed by the formation of BODIPY triplet excited states via spin-orbit charge transfer intersystem crossing (SOCT-ISC) was studied by steady-state and ultrafast pump-probe transient optical spectroscopy. Highly efficient photosensitization was observed for dyads bearing pyrene and anthracene substituents, which exhibited singlet oxygen generation quantum yields () of up to 94%. Charge transfer and SOCT-ISC were observed in non-polar solvent (toluene) due to the increased electron accepting ability of the diethoxycarbonyl-BODIPY. …

Beam Dynamics Simulations And Systematic Studies For The Muon G-2 Experiment At Fermilab, Abel M. Lorente Campos

Theses and Dissertations--Physics and Astronomy

The first results of the positive muon anomalous magnetic moment from the Muon g-2 Experiment at Fermilab differs from the Standard Model prediction by 3.3 standard deviations, with an experimental uncertainty of 0.46 ppm. Combining this result with the previous measurement from the Brookhaven National Laboratory, it sets the difference between experiment and theory at 4.2 standard deviations. The goal of the Muon g-2 Experiment at Fermilab is to increase this discrepancy to 5 standard deviations, which would require unprecedented precision in the measurements of 0.14 ppm. Of significant importance to achieving this precision, beam and spin dynamics simulations are …

Nonequilibrium Dynamics Of Correlated Disordered Systems Under Interaction Quenches, Eric A. Dohner

Legacy Theses & Dissertations (2009 - 2024)

Correlated, disordered lattice fermion systems out of equilibrium have been understudied, at least in part for lack of tools to study them. The development of a new method, the NE-DMFT+CPA, is explicated, for investigating the properties of these systems. This method combines DMFT and the CPA using the Kadanoff-Baym-Keldysh contour-time formalism to study the dynamics of interacting disordered systems out of equilibrium. The method is detailed, then applied to the case of the Anderson-Hubbard model: first to replicate well-known equilibrium results, then to study the case of the model under the effect of an interaction quench. Here the effect of …

Kinesin And Myosin Motors Compete To Drive Rich Multiphase Dynamics In Programmable Cytoskeletal Composites, Ryan Mcgorty Phd, Christopher Currie, Jonathan Michel, Mehrad Sasanpour, Christopher Gunter, K Alice Lindsay, Michael J. Rust, Parag Katira, Moumita Das, Jennifer L. Ross, Rae M. Robertson-Anderson

Physics and Biophysics: Faculty Scholarship

The cellular cytoskeleton relies on diverse populations of motors, filaments, and binding proteins acting in concert to enable nonequilibrium processes ranging from mitosis to chemotaxis. The cytoskeleton's versatile reconfigurability, programmed by interactions between its constituents, makes it a foundational active matter platform. However, current active matter endeavors are limited largely to single force-generating components acting on a single substrate—far from the composite cytoskeleton in cells. Here, we engineer actin–microtubule (MT) composites, driven by kinesin and myosin motors and tuned by crosslinkers, to ballistically restructure and flow with speeds that span three orders of magnitude depending on the composite formulation and …

Cooperative Rheological State-Switching Of Enzymatically-Driven Composites Of Circular Dna And Dextran, Juexin Marfai, Ryan Mcgorty, Rae M. Robertson-Anderson

Physics and Biophysics: Faculty Scholarship

Polymer topology, which plays a principal role in the rheology of polymeric fluids, and non-equilibrium materials, which exhibit time-varying rheological properties, are topics of intense investigation. Here, composites of circular DNA and dextran are pushed out-of-equilibrium via enzymatic digestion of DNA rings to linear fragments. These time-resolved rheology measurements reveal discrete state-switching, with composites undergoing abrupt transitions between dissipative and elastic-like states. The gating time and lifetime of the elastic-like states, and the magnitude and sharpness of the transitions, are surprisingly decorrelated from digestion rates and non-monotonically depend on the DNA fraction. These results are modeled using sigmoidal two-state functions …

The Post-Shock Nonequilibrium Relaxation In A Hypersonic Plasma Flow Involving Reflection Off A Thermal Discontinuity, Anna Markhotok

Physics Faculty Publications

The evolution in the post shock nonequilibrium relaxation in a hypersonic plasma flow was investigated during a shock’s reflection off a thermal discontinuity. Within a transitional period, the relaxation zone parameters past both, the reflected and transmitted waves, evolve differently compared to that in the incident wave. In a numerical example for the non-dissociating N₂ gas heated to 5000 K/10,000 K across the interface and M = 3.5, the relaxation time for the transmitted wave is up to 50% shorter and the relaxation depth for both waves is significantly reduced, thus resulting in a weakened wave structure. The …

Quantum Efficiency Enhancement In Simulated Nanostructured Negative Electron Affinity Gaas Photocathodes, Md Aziz Ar Rahman, Shukui Zhang, Hani E. Elsayed-Ali

Physics Faculty Publications

Nanostructured negative electron affinity GaAs photocathodes for a polarized electron source are studied using finite difference time domain optical simulation. The structures studied are nanosquare columns, truncated nanocones, and truncated nanopyramids. Mie-type resonances in the 700–800 nm waveband, suitable for generation of polarized electrons, are identified. At resonance wavelengths, the nanostructures can absorb up to 99% of the incident light. For nanosquare columns and truncated nanocones, the maximum quantum efficiency (QE) at 780 nm obtained from simulation is 27%, whereas for simulated nanopyramids, the QE is ∼21%. The high photocathode quantum efficiency is due to the shift of Mie resonance …

Gluon Transverse-Momentum-Dependent Distributions From Large-Momentum Effective Theory, Ruilin Zhu, Yao Ji, Jian-Hui Zhang, Shuai Zhao

Physics Faculty Publications

We demonstrate that gluon transverse-momentum-dependent parton distribution functions (TMDPDFs) can be extracted from lattice calculations of appropriate Euclidean correlations in large-momentum effective theory (LaMET). Based on perturbative calculations of gluon unpolarized and helicity TMDPDFs, we present a matching formula connecting them and their LaMET counterparts, where the latter are renormalized in a scheme facilitating lattice calculations and converted to the MS ¯ scheme. The hard matching kernel is given up to one-loop level. We also show that the perturbative result is independent of the prescription used for the pinch-pole singularity in the relevant correlations. Our results offer a guidance for …

Prospects For 𝛾*𝛾* → 𝜋𝜋 Via Lattice Qcd, Raúl Briceño, Andrew W. Jackura, Arkaitz Rodas, Juan V. Guerrero

Physics Faculty Publications

The 𝛾*𝛾* → 𝜋𝜋 scattering amplitude plays a key role in a wide range of phenomena, including understanding the inner structure of scalar resonances as well as constraining the hadronic contributions to the anomalous magnetic moment of the muon. In this work, we explain how the infinite-volume Minkowski amplitude can be constrained from finite-volume Euclidean correlation functions. The relationship between the finite-volume Euclidean correlation functions and the desired amplitude holds up to energies where 3𝜋 states can go on shell, and is exact up to exponentially small corrections that scale like 𝒪(e^−m𝜋L), where L is the spatial extent …

Observation Of Correlations Between Spin And Transverse Momenta In Back-To-Back Dihadron Production At Clas12, H. Avakian, T.B. Hayward, A. Kotzinian, W.R. Armstrong, H. Atac, C. Ayerbe Gayoso, L. Baashen, N.A. Balzell, L. Barion, M. Bashkanov, M. Battaglieri, I. Bedlinskiy, B. Benkel, F. Benmokhtar, A. Bianconi, L. Biondo, A. S. Biselli, M. Bondi, S. Boiarinov, M. Zurek, Et Al.

Physics Faculty Publications

We report the first measurements of deep inelastic scattering spin-dependent azimuthal asymmetries in back-to-back dihadron electroproduction in the deep inelastic scattering process. In this reaction, two hadrons are produced in opposite hemispheres along the z axis in the virtual photon-target nucleon center-of-mass frame, with the first hadron produced in the current-fragmentation region and the second in the target-fragmentation region. The data were taken with longitudinally polarized electron beams of 10.2 and 10.6 GeV incident on an unpolarized liquid-hydrogen target using the CLAS12 spectrometer at Jefferson Lab. Observed nonzero sinΔϕ modulations in ep→e'pπ⁺ X events, where Δϕ is the difference …

A Multidimensional Study Of The Structure Function Ratio Σlt'/ Σ₀ From Hard Exclusive ��⁺ Electro-Production Off Protons In The Gpd Regime, S. Diehl, A. Kim, K. Joo, P. Achenbach, Z. Akbar, M. J. Amaryan, H. Atac, H. Avagyan, C. Ayerbe Gayoso, L. Baashen, L. Barion, M. Bashkanov, M. Battaglieri, I. Bedlinsky, B. Benkel, F. Benmokhtar, A. Bianconi, A. S. Biselli, M. Bondi, W.A. Booth, M. Zurek, Et Al.

Physics Faculty Publications

A multidimensional extraction of the structure function ratio from the hard exclusive ^→ep → e'n��+ reaction above the resonance region has been performed. The study was done based on beam-spin asymmetry measurements using a 10.6 GeV incident electron beam on a liquid-hydrogen target and the CLAS12 spectrometer at Jefferson Lab. The measurements focus on the very forward regime (t/Q²≪ 1) with a wide kinematic range of in the valence regime (0.17 < ��_B < 0.55), and virtualities ranging from 1.5 GeV² up to 6 GeV². The results and their comparison to theoretical models based on Generalized Parton Distributions demonstrate the sensitivity to chiral-odd …

Determination Of The Titanium Spectral Function From (E, E'P) Data, L. Jiang, A.M. Ankowski, D. Abrams, L. Gu, B. Aljawrneh, S. Alsalmi, J. Bane, A. Batz, S. Barcus, M. Barroso, V. Bellini, O. Benhar, J. Bericic, D. Biswas, A. Camsonne, J. Castellanos, J. -P. Chen, M. E. Christy, K. Craycraft, R. Cruz-Torres, H. Dai, D. Day, A. Dirican, S. -C. Dusa, E. Fuchey, T. Gautam, C. Giusti, J. Gomez, C. Gu, T. J. Hague, J. -O. Hansen, F. Hauenstein, D. W. Higinbotham, C. Hyde, Z. Jerzyk, A. M. Johnson, C. Keppel, C. Lanham, S. Li, R. Lindgren, H. Liu, C. Mariani, R. E. Mcclellan, D. Meekins, R. Michaels, M. Mihovilovic, M. Murphy, D. Nguyen, M. Nycz, L. Ou, B. Pandey, V. Pandey, K. Park, G. Perera, A.J.R. Puckett, S.N. Santiesteban, S. Ŝirca, T. Su, L. Tang, Y. Tian, N. Ton, B. Wojsekhowski, S. Wood, Z. Ye, J. Zhang

Physics Faculty Publications

The E12-14-012 experiment, performed in Jefferson Lab Hall A, has measured the (e,e′p) cross section in parallel kinematics using a natural titanium target. In this paper, we report the analysis of the dataset obtained in different kinematics for our solid natural titanium target. Data were obtained in a range of missing momentum and missing energy between 15 ≲ p_m ≲ 250  MeV/c and 12 ≲ Em ≲ 80  MeV, respectively, and using an electron beam energy of 2.2 GeV. We measured the reduced cross section with ∼7% accuracy as a function of both missing momentum and missing energy. …

Exclusive 𝝅⁻ Electroproduction Off The Neutron In Deuterium In The Resonance Region, Y. Tian, R. W. Gothe, V. I. Mokeev, G. Hollis, M. J. Amaryan, W. R. Armstrong, H. Atac, H. Avakian, L. Barion, M. Battaglieri, I. Bedlinskiy, B. Benkel, F. Benmokhtar, A. Bianconi, L. Biondo, A. Biselli, F. Bossù, S. Boiarinov, M. Bondì, J. Zhang, Et Al., The Clas Collaboration

Physics Faculty Publications

New results for the exclusive and quasifree cross sections off neutrons bound in deuterium 𝛾_vn(p) → pπ− (p) are presented over a wide final state hadron angle range with a kinematic coverage of the invariant mass (W) up to 1.825 GeV and the four-momentum transfer squared (Q²) from 0.4 to 1.0 GeV². The exclusive structure functions were extracted and their Legendre moments were obtained. Final-state-interaction contributions have been kinematically separated from the extracted quasifree cross sections off bound neutrons solely based on the analysis of the experimental data. These new results will serve as …

Generation And Characterization Of Magnetized Electron Beam From A Dc High Voltage Photogun For Electron Beam Cooling Application, S.A.K. Wijethunga, M. A. Mamun, R. Suleiman, P. Adderley, B. Bullard, J. Benesch, Jean R. Delayen, J. Grames, C. Hernandez-Garcia, F. Hannon, Geoffrey A. Krafft, G. Palacios-Serrano, M. Poelker, M. Stefani, Y. Wang, S. Zhang

Physics Faculty Publications

One of the most challenging requirements for the proposed Electron–Ion Collider is the strong cooling of the proton beam, which is key to achieving the collider’s desired luminosity of order 10³³–10³⁴cm⁻²s⁻¹. Magnetized bunched-beam electron cooling could be a means to achieve the required high luminosity, where strong cooling is accomplished inside a cooling solenoid where the ions co-propagate with an electron beam generated from a source immersed in a magnetic field. To increase the cooling efficiency, a bunched electron beam with high bunch charge and high repetition rate is required. This work …

Modeling A Nb3Sn Cryounit In Gpt At Uitf, Sunil Pokharel, A. S. Hofler, Geoffrey A. Krafft

Physics Faculty Publications

Nb₃Sn is a prospective material for future superconducting radio frequency (SRF) accelerator cavities. Compared to conventional niobium, the material can achieve higher quality factors, higher temperature operation, and potentially higher accelerating gradients (E_acc ≈ 96 MV/m). In this work, we performed modeling of the Upgraded Injector Test Facility (UITF) at Jefferson Lab utilizing newly constructed Nb₃Sn cavities. We studied the effects of the buncher cavity and varied the gun voltage from 200-500 keV. We have calibrated and optimized the SRF cavity gradients and phases for the Nb₃Sn five-cell cavities' energy gains with the …