Nuclear Commons^™

Beam Energy Dependence Of Jet-Quenching Effects In Au + Au Collisions At √SNn = 7.7, 11.5, 14.5, 19.6, 27, 39, And 62.4 Gev, L. Adamczyk, J. R. Adams, J. Kevin Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, N. N. Ajitanand, I. Alekseev, D. M. Anderson, R. Aoyama, A. Aparin, D. Arkhipkin, E. C. Aschenauer, M. U. Ashraf, A. Attri, G. S. Averichev, X. Bai, V. Bairathi, K. Barish, A. Behera, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, J. Bielcikova, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. Bouchet, J. D. Brandenburg, Renee H. Fatemi, Suvarna Ramachandran

Physics and Astronomy Faculty Publications

We report measurements of the nuclear modification factor RCP for charged hadrons as well as identified π⁺⁽⁻⁾, K⁺⁽⁻⁾, and p^(p¯) for Au + Au collision energies of √s_NN = 7.7, 11.5, 14.5, 19.6, 27, 39, and 62.4 GeV. We observe a clear high-pT net suppression in central collisions at 62.4 GeV for charged hadrons which evolves smoothly to a large net enhancement at lower energies. This trend is driven by the evolution of the pion spectra but is also very similar for the kaon spectra. While the magnitude of the proton R_{CP …}

Search For The Neutron Decay N → X+Γ, Where X Is A Dark Matter Particle, Z. Tang, M. Blatnik, L. J. Broussard, J. H. Choi, S. M. Clayton, C. Cude-Woods, S. Currie, D. E. Fellers, E. M. Fries, P. Geltenbort, F. Gonzalez, K. P. Hickerson, T. M. Ito, C. -Y. Liu, S. W. T. Macdonald, M. Makela, C. L. Morris, C. M. O'Shaughnessy, R. W. Pattie Jr., Bradley R. Plaster, D. J. Salvat, A. Saunders, Z. Wang, A. R. Young, B. A. Zeck

Physics and Astronomy Faculty Publications

Fornal and Grinstein recently proposed that the discrepancy between two different methods of neutron lifetime measurements, the beam and bottle methods, can be explained by a previously unobserved dark matter decay mode, n → X+γ. We perform a search for this decay mode over the allowed range of energies of the monoenergetic γ ray for X to be dark matter. A Compton-suppressed high-purity germanium detector is used to identify γ rays from neutron decay in a nickel-phosphorous-coated stainless-steel bottle. A combination of Monte Carlo and radioactive source calibrations is used to determine the absolute efficiency for detecting …

First Measurement Of The Ti(E, É) X Cross Section At Jefferson Lab, Jefferson Lab Hall A Collaboration, F. Hauenstein, C. Hyde

Physics Faculty Publications

To probeCPviolation in the leptonic sector usingGeVenergy neutrino beams in current and future experiments using argon detectors, precise models of the complex underlying neutrino and antineutrino interactions are needed. The E12-14-012 experiment at JeffersonLab HallAwas designed to perform a combined analysis of inclusive and exclusive electron scatterings on both argon (N = 22) and titanium (Z = 22) nuclei using GeV-energy electron beams. Themeasurement on titanium nucleus provides essential information to understand the neutrino scattering on argon, large contribution to which comes from scattering off neutrons. Here we report the first experimental study of electron-titanium scattering as double-differential cross section …

Ion Bunch Formation Strategies For The Jleic Collider, Bamunuvita Randika Prasad Gamage

Physics Theses & Dissertations

An Electron-Ion Collider (EIC) has been proposed and supported as the next major nuclear physics facility in the United States, with very high design luminosities of 10³³ − 10³⁴ cm⁻² s⁻¹. The Jefferson Lab EIC concept, JLEIC, includes construction of a new ion beam accelerator complex. To achieve the required luminosity, the JLEIC ion collider requires unprecedentedly short ion bunches of 1 cm length at a high repetition frequency of 476 MHZ. However, only much longer ion bunches are formed by the ion injector complex producing beams for the collider ring. Formation of short ion …

Differential Cross Section For Γ D →Ωd Using Clas At Jefferson Lab, T. Chetry, K. Hicks, N. Compton, S. Adhikari, J. Ball, G. Charles, M. Khachatryan, Y. Prok, L. B. Weinstein, Z. W. Zhao

Physics Faculty Publications

The cross section for coherent ω-meson photoproduction off the deuteron has been measured for the first time as a function of the momentum transfer t=(P_γ−P_ω)² and photon energy E_γ using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cross sections are measured in the energy range 1.4 γ<3.4 GeV. A model based on ω−N rescattering is consistent with the data at low and intermediate momentum transfer, |t|. For 2.8 γ<3.4 GeV, the total cross-section of ω−N scattering, based on fits within the framework of the Vector Meson Dominance model, is in the range of 30–40 mb.

Recommended Corrective Security Measures To Address The Weaknesses Identified Within The Shapash Nuclear Research Institute, Khadija Moussaid, Oum Keltoum Hakam

International Journal of Nuclear Security

The Shapash Nuclear Research Institute (SNRI) data book was issued by the International Atomic Energy Agency (IAEA) in 2013. The hypothetical facility data book describes the hypothetical site, which is divided into two areas: the low-security area, known as the administrative area, and the very high-security area, known as the protected area. The book contains detailed descriptions of each area’s safety and security measures, along with figures of multiple buildings in both areas, and also includes information about the site’s computer networks.

This paper aims to identify security weaknesses related to the institute’s location, the Administrative Area (AA), the Protected …

Conducting Nuclear Security Culture Self-Assessments In Nuclear Research Facilities Using The Iaea Methodology, Anhar Riza Antariksawan, Khairul Khairul, Heru Umbara, Endang Kristuti, Bayu Purnomo

International Journal of Nuclear Security

The National Nuclear Energy Agency of Indonesia (BATAN) has promoted the culture and assessment of nuclear security in Indonesia since 2010. After conducting a successful trial assessment in 2012, BATAN performed a second self-assessment in 2015 in three nuclear facilities. The assessment's methodology followed the guidelines set by the International Atomic Energy Agency (IAEA). The objective of this paper is to demonstrate the techniques used in applying the IAEA methodology and to discuss the primary outcomes of the assessment. The data collection consisted of surveys, interviews, document reviews, and observations. A total of about 50% of the three facilities’ employees …

Measurement Of The 3ΛH Lifetime In Au+Au Collisions At The Bnl Relativistic Heavy Ion Collider, L. Adamczyk, J. R. Adams, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, N. N. Ajitanand, I. Alekseev, J. Alford, D. M. Anderson, R. Aoyama, A. Aparin, D. Arkhipkin, E. C. Aschenauer, M. U. Ashraf, A. Attri, G. S. Averichev, X. Bai, V. Bairathi, K. Barish, A. Behera, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. Bouchet, Renee H. Fatemi, Suvarna Ramachandran

Physics and Astronomy Faculty Publications

An improved measurement of the ³_ΛH lifetime is presented. In this paper, the mesonic decay modes ³_ΛH → ³He + π⁻ and ³_ΛH → d + p + π⁻ are used to reconstruct the ³_ΛH from Au+Au collision data collected by the STAR collaboration at Relativistic Heavy Ion Collider (RHIC). A minimum χ² estimation is used to determine the lifetime of τ = 142⁺²⁴₋₂₁(stat.) ± 29(syst.) ps. This lifetime is about 50% shorter than the lifetime τ = 263 ± 2 ps of a free …

Search For Dark Matter Decay Of The Free Neutron From The Ucna Experiment: N → Χ + E+E−, X. Sun, E. Adamek, B. Allgeier, M. Blatnik, T. J. Bowles, L. J. Broussard, M. A. -P. Brown, R. Carr, S. Clayton, C. Cude-Woods, S. Currie, E. B. Dees, X. Ding, B. W. Filippone, A. García, P. Geltenbort, S. Hasan, K. P. Hickerson, J. Hoagland, R. Hong, G. E. Hogan, A. T. Holley, T. M. Ito, A. Knecht, C. -Y. Liu, J. Liu, M. Makela, R. Mammei, J. W. Martin, D. Melconian, Subash C. Nepal, Bradley R. Plaster

Physics and Astronomy Faculty Publications

It has been proposed recently that a previously unobserved neutron decay branch to a dark matter particle (χ) could account for the discrepancy in the neutron lifetime observed in experiments that use two different measurement techniques. One of the possible final states discussed includes a single χ along with an e⁺e⁻ pair. We use data from the UCNA (Ultracold Neutron Asymmetry) experiment to set limits on this decay channel. Coincident electron-like events are detected with ∼4π acceptance using a pair of detectors that observe a volume of stored ultracold neutrons. The summed kinetic energy (E_{e …}

The Impact Of Ppb W/Z Lhc Data On Ncteq15 Parton Distribution Functions With An Emphasis On Refitting The Ncteq15 Npdf Set, Eric Godat

Physics Theses and Dissertations

As the LHC experiments increase their statistics and reduce their systematics, it is in- creasingly important to reduce the theoretical uncertainties so we can perform precision com- parisons. The parton distribution functions (PDFs) which describe the hadronic structure of protons and nuclei are the critical link between the experimental data and the proposed theoretical models; hence, a better understanding of the PDFs is essential for improved pre- dictions. Nuclear PDFs, in particular, have proven valuable in this regard, especially for flavor differentiation. I introduce ”nCTEQ+LHC,” the first PDF set fit using the nCTEQ formalism to include data from the LHC. …

An Analysis Of Frenkel Defects And Backgrounds Modeling For Supercdms Dark Matter Searches, Matthew Stein

Physics Theses and Dissertations

Years of astrophysical observations suggest that dark matter comprises more than ~80 % of all matter in the universe. Particle physics theories favor a weakly-interacting particle that could be directly detected in terrestrial experiments. The Super Cryogenic Dark Matter Search (SuperCDMS) Collaboration operates world-leading experiments to directly detect dark matter interacting with ordinary matter. The SuperCDMS Soudan experiment searched for weakly interacting massive particles (WIMPs) via their elastic-scattering interactions with nuclei in low-temperature germanium detectors.

During the operation of the SuperCDMS Soudan experiment, ²¹⁰Pb sources were installed to study background rejection of the Ge detectors. Data from these sources …

Evaluation Of A Continuous Air Monitoring System On An Unmanned Aerial Vehicle For Measurement Of Airborne Radioactive Material, Adam Pfannenstein

UNLV Theses, Dissertations, Professional Papers, and Capstones

The release of airborne radioactive material presents a health risk hazard to many individuals, emergency responders and public. It is necessary to characterize the unknown radioactive dangers produced in the event of these incidents. Advantages to utilizing unmanned aerial systems in this effort are personnel risk reduction and quick attainment of data points in a plume. By pairing a continuous air monitor and detector with a drone, radioactive material concentration can be quantified, and thus the extent of potential doses can be estimated. A small, low-flow air sampler with a Geiger-Mueller counter was characterized using measurements of sources representing a …

Design & Delivery Of Automated Winston-Lutz Test For Isocentric & Off-Axis Delivery Stability Utilizing Truebeam Developer Mode & Electronic Portal Imaging Device, Mahmoud Mohammad Yaqoub

UNLV Theses, Dissertations, Professional Papers, and Capstones

The uncertainties in treatment delivery cannot be ignored in radiation therapy. Thus, the quality assurance QA tests are very important task of the medical physicist in clinical practice. Assuring the coincidence between the mechanical isocenter of the Linear Accelerator (LINAC) and its radiation beams isocenter is one of the most important qualities need to be tested, and the Winston Lust (WL) test is the

most popular technique to perform this task, especially for the treatment modalities which need high precision in beam delivery such as the stereotactic radiosurgery/stereotactic body radiotherapy (SRS/SBRT). The linear accelerator-based SRS/SBRT is a well-established method in …

Measurement Of The Beam Asymmetry Σ And The Target Asymmetry T In The Photoproduction Of Ω Mesons Off The Proton Using Clas At Jefferson Laboratory, P. Roy, Z. Akbar, S. Park, V. Crede, A. V. Anisovich, I. Denisenko, E. Klempt, V. A. Nikonov, A. V. Sarantsev, K. P. Adhikari, S. Adhikari, S. Anefalos Pereira, J. Ball, I. Balossino, M. Bashkanov, M. Battaglieri, V. Batourine, I. Bedlinskiy, A. S. Biselli, S. Boiarinov, W. J. Briscoe, J. Brock, W. K. Brooks, V. D. Burkert, C. Carlin, D. S. Carman, A. Celentano, G. Charles, T. Chetry, G. Ciullo, Wesley P. Gohn

Physics and Astronomy Faculty Publications

The photoproduction of ω mesons off the proton has been studied in the reaction γp → pω using the CEBAF Large Acceptance Spectrometer (CLAS) and the frozen-spin target in Hall B at the Thomas Jefferson National Accelerator Facility. For the first time, the target asymmetry T has been measured in photoproduction from the decay ω → π⁺π⁻π⁰, using a transversely polarized target with energies ranging from just above the reaction threshold up to 2.8 GeV. Significant nonzero values are observed for these asymmetries, reaching about 30–40% in the third-resonance region. New measurements for the …

Hard Exclusive Pion Electroproduction At Backward Angles With Clas, K. Park, M. Guidal, R. W. Gothe, B. Pire, G. Charles, C. E. Hyde, S E. Kuhn, J. Poudel, Y. Prok

Physics Faculty Publications

We report on the first measurement of cross sections for exclusive deeply virtual pion electroproduction off the proton, ep → e'nπ⁺, above the resonance region at backward pion center-of-mass angles. The ϕ∗ π-dependent cross sections were measured, from which we extracted three combinations of structure functions of the proton. Our results are compatible with calculations based on nucleon-to-pion transition distribution amplitudes (TDAs). These non-perturbative objects are defined as matrix elements of threequark-light-cone-operators and characterize partonic correlations with a particular emphasis on baryon charge distribution inside a nucleon.

Developing Kenya’S Educational Capacity In Nuclear Security Through Nuclear Forensics Research, Hudson Kalambuka Angeyo

International Journal of Nuclear Security

Nuclear energy’s distinctive characteristics give rise to special educational requirements. These requirements are necessary to not only address the danger of nuclear proliferation, but also to build capacity for a secure nuclear fuel circle. In this paper, I assess the status of educational capacity in nuclear security both in response to, and in support of, Kenya’s nuclear power program. I highlight the nuclear security educational infrastructure’s key features in the context of nuclear power, noting the low capacity at Kenyan universities. I identify the steps required to ensure that the country’s dynamic nuclear regulatory infrastructural framework is used effectively to …

An Exploration Of The Optical Detection Of Ionizing Radiation Utilizing Modern Optics Technology, Sean D. Fournier, Adam Hecht, Cassiano De Oliveira, Jeffrey B. Martin, Richard K. Harrison, Charles Potter

Nuclear Engineering ETDs

Modern ultraviolet (UV) cameras, when combined with UV-transmitting lenses/filter arrangements, can be used to detect radiation dose in air. Ionizing radiation excites nitrogen molecules in ambient air, the resulting decay includes weak emission of ultraviolet photons. Previous work has proven this phenomenon is detectable using highly-sensitive electronically cooled cameras traditionally used in astronomy for low-background imaging. While the ability to detect the presence of radiation (i.e. qualitative measurement) has been demonstrated at Sandia National Laboratories, there are several challenges in correlating images to known dose-fields (quantitative measurement). These challenges include: a low signal to background ratio, interferences due to electronic …

Nucleon And Nuclear Structure Through Dilepton Production, I. V. Anikin, N. Baltzell, M. Boer, R. Boussarie, V. M. Braun, S. J. Brodsky, A. Camsonne, W. C. Chang, L. Colaneri, C. E. Hyde

Physics Faculty Publications

Transverse momentum distributions and generalized parton distributions provide a comprehensive framework for the three-dimensional imaging of the nucleon and the nucleus experimentally using deeply virtual semi-exclusive and exclusive processes. The advent of combined high luminosity facilities and large acceptance detector capabilities enables experimental investigation of the partonic structure of hadrons with time-like virtual probes, in complement to the rich on-going space-like virtual probe program. The merits and benefits of the dilepton production channel for nuclear structure studies are discussed within the context of the International Workshop on Nucleon and Nuclear Structure through Dilepton Production taking place at the European Center …

Novel Topological Effects In Dense Qcd In A Magnetic Field, E.J. Ferrer, V. De La Incera

Publications and Research

We study the electromagnetic properties of dense QCD in the so-called Magnetic Dual Chiral Density Wave phase. This inhomogeneous phase exhibits a nontrivial topology that comes from the fermion sector due to the asymmetry of the lowest Landau level modes. The nontrivial topology manifests in the electromagnetic effective action via a chiral anomaly term $\theta F^{\mu\nu}\tilde{F}_{\mu\nu}$, with a dynamic axion field θ given by the phase of the Dual Chiral Density Wave condensate. The coupling of the axion with the electromagnetic field leads to several macroscopic effects that include, among others, an anomalous, nondissipative Hall current, an anomalous electric charge, …

New Result For The Neutron Β-Asymmetry Parameter A0 From Ucna, M. A.-P. Brown, E. B. Dees, E. Adamek, B. Allgeier, M. Blatnik, T. J. Bowles, L. J. Broussard, R. Carr, S. Clayton, C. Cude-Woods, S. Currie, X. Ding, B. W. Filippone, A. García, P. Geltenbort, S. Hasan, K. P. Hickerson, J. Hoagland, R. Hong, G. E. Hogan, A. T. Holley, T. M. Ito, A. Knecht, C. -Y. Liu, J. Liu, M. Makela, J. W. Martin, D. Melconian, M. P. Mendenhall, S. D. Moore, Subash C. Nepal, N. Nouri, Bradley R. Plaster

Physics and Astronomy Faculty Publications

Background: The neutron β-decay asymmetry parameter A₀ defines the angular correlation between the spin of the neutron and the momentum of the emitted electron. Values for A₀ permit an extraction of the ratio of the weak axial-vector to vector coupling constants, λ ≡ g_A/g_V, which under assumption of the conserved vector current hypothesis (g_V = 1) determines g_A. Precise values for g_A are important as a benchmark for lattice QCD calculations and as a test of the standard model.

Purpose: The UCNA experiment, carried out at the …