Physics Commons^™

Afci Quarterly Input – Unlv October 1 Through December 31, 2006, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects, activities and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

The University of Nevada, Las Vegas supports the AFCI through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support.

Single Top Quark Production At The Fermilab Tevatron: Threshold Resummation And Finite-Order Soft Gluon Corrections, Nikolaos Kidonakis

Faculty and Research Publications

I present a calculation of threshold soft-gluon corrections to single top-quark production in p(p) collisions via all partonic processes in the t and s channels and via associated top quark and W boson production. The soft-gluon corrections are formally resummed to all orders, and finite-order expansions of the resummed cross section are calculated through next-to-next-to-next-to-leading-order (NNNLO) at next-to-leading logarithmic (NLL) accuracy. Numerical results for single top-quark production at the Tevatron are presented, including the dependence of the cross sections on the top-quark mass and on the factorization and renormalization scales. The threshold corrections in the t channel are small while …

Upper Bounds On Parity-Violating Gamma-Ray Asymmetries In Compound Nuclei From Polarized Cold Neutron Capture, M. T. Gericke, J. D. Bowman, R. D. Carlini, T. E. Chupp, K. P. Coulter, M. Dabaghyan, M. Dawkins, D. Desai, S. J. Freedman, T. R. Gentile, R. C. Gillis, G. L. Greene, F. W. Hersman, T. Ino, Gordon L. Jones, M. Kandes, B. Lauss, M. Leuschner, W. R. Lozowski, R. Mahurin, M. Mason, Y. Masuda, G. S. Mitchell, S. Muto, H. Nann, S. A. Page, S. I. Penttila, W. D. Ramsay, S. Santra, P.-N. Seo, E. I. Sharapov, T. B. Smith, W. M. Snow, W. S. Wilburn, V. Yuan, H. Zhu

Articles

Parity-odd asymmetries in the electromagnetic decays of compound nuclei can sometimes be amplified above values expected from simple dimensional estimates by the complexity of compound nuclear states. Using a statistical approach, we estimate the root-mean-square of the distribution of expected parity-odd correlations (s) over right arrow (n)center dot(k) over right arrow (gamma), where (s) over right arrow (n) is the neutron spin and (k) over right arrow (gamma) is the momentum of the gamma, in the integrated gamma spectrum from the capture of cold polarized neutrons on Al, Cu, and In. We present measurements of the asymmetries in these and …

Afci Quarterly Input – Unlv July 1 Through September 30, 2006, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects, activities and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

The University of Nevada, Las Vegas supports the AFCI through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support.

Low-Energy Nondipole Effects In Molecular Nitrogen Valence-Shell Photoionization, Oliver Hemmers, Renaud Guillemin, D. Rolles, A. Wolska, Dennis W. Lindle, E. P. Kanter, B. Krassig, S. H. Southworth, R. Wehlitz, B. Zimmermann, V. Mckoy, P. W. Langhoff

Environmental Studies Faculty Publications

Observations are reported for the first time of significant nondipole effects in the photoionization of the outer-valence orbitals of diatomic molecules. Measured nondipole angular-distribution parameters for the 3σ_g, 1π_u, and 2σ_u shells of N₂ exhibit spectral variations with incident photon energies from thresholds to ∼200  eV which are attributed via concomitant calculations to particular final-state symmetry waves arising from (E1)⊗(M1,E2) radiation-matter interactions first-order in photon momentum. Comparisons with previously reported K-edge studies in N₂ verify linear scaling with photon momentum, accounting in part for the significantly enhanced nondipole behavior observed in inner-shell ionization …

Revisiting Anomalous B(E2;4+1→2+1)/B(E2;2+1→0+1) Values In 98Ru And 180Pt, E. Williams, C. Plettner, E. A. Mccutchan, H. Levine, N. V. Zamfir, R. Cakirli, R. F. Casten, H. Ai, C. W. Beausang, G. Gurdal, A. Heinz, J. Qian, D. A. Meyer, N. Pietralla, V. Werner

Physics Faculty Publications

Recently, a set of nine nonmagic nuclei with anomalous values of the B(E2) ratio B_4/2 ≡ B(E2; 4⁺₁ → 2⁺₁)/B(E2; 2⁺₁ → 0⁺₁) were identified. Such values are outside the range allowed by current collective models. In the present work, the B(E2; 4⁺₁ → 2⁺₁) values for two of these nuclei, ⁹⁸Ru and ¹⁸⁰Pt, were re-measured to determine if the current literature values for these nuclei are correct. ^{98 …}

Collectivity And Configuration Mixing In 186,188Pb And 194Po, T. Grahn, A. Dewald, O. Moller, R. Julin, C. W. Beausang, S. Christen, I. G. Darby, S. Eeckhaudt, P. T. Greenlees, A. Gorgen, K. Helariutta, J. Jolie, P. Jones, S. Juutinen, H. Kettunen, T. Kroll, R. Krucken, Y. Le Coz, M. Leino, A. P. Leppanen, P. Maierbeck, D. A. Meyer, B. Melon, P. Nieminen, M. Nyman, R. D. Page, J. Pakarinen, P. Petkov, P. Rahkila, B. Saha, M. Sandzelius, J. Saren, C. Scholey, J. Uusitalo

Physics Faculty Publications

Lifetimes of prolate intruder states in ¹⁸⁶Pb and oblate intruder states in ¹⁹⁴Po have been determined by employing, for the first time, the recoil-decay tagging technique in recoil distance Doppler-shift lifetime measurements. In addition, lifetime measurements of prolate states in ¹⁸⁸Pb up to the 8⁺state were carried out using the recoil-gating method. The B(E2) values have been deduced from which deformation parameters lβ₂l = 0.29(5) and lβ₂l = 0.17(3) for the prolate and the oblate bands, respectively, have been extracted. The results also shed new light on the …

Transport Of Galectin-3 Between The Nucleus And Cytoplasm. Ii. Identification Of The Signal For Nuclear Export, Su Yin Li, Peter J. Davidson, Nancy Y. Lin, Ronald J. Patterson

University Faculty Publications and Creative Works

Galectin-3, a factor involved in the splicing of pre-mRNA, shuttles between the nucleus and the cytoplasm. Previous studies have shown that incubation of fibroblasts with leptomycin B resulted in the accumulation of galectin-3 in the nucleus, suggesting that the export of galectin-3 from the nucleus may be mediated by the CRM1 receptor. A candidate nuclear export signal fitting the consensus sequence recognized by CRM1 can be found between residues 240 and 255 of the murine galectin-3 sequence. This sequence was engineered into the pRev(1.4) reporter system, in which candidate sequences can be tested for nuclear export activity in terms of …

Dissolution, Reactor, And Environmental Behavior Of Zro 2 -Mgo Inert Fuel Matrix Neutronic Evaluation Of Mgo-Zro2 Inert Fuels, E. Fridman, A. Galperin, E. Shwageraus

Fuels Campaign (TRP)

In the second year of the “Dissolution, Reactor, and Environmental Behavior of ZrO₂-MgO Inert Fuel Matrix” project initiated and directed by UNLV, the Ben-Gurion University (BGU) group research was focused on the development of practical PWR core nuclear design fully loaded with Reactor Grade (RG) Pu fuel incorporated in fertile free matrix. The design strategy was based on the basic feasibility study results performed at BGU in the Year 1 of the project.

Afci Quarterly Input – Unlv April 1 Through June 30, 2006, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects, activities and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

The University of Nevada, Las Vegas supports the AFCI through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support.

Deducing The 237U(N,F) Cross Section Using The Surrogate Ratio Method, J. T. Burke, L. A. Bernstein, J. Escher, L. Ahle, J. A. Church, F. S. Dietrich, K. Moody, E. B. Norman, L. Phair, P. Fallon, R. M. Clark, M. A. Deleplanque, M. Descovich, M. Cromaz, I. Y. Lee, A. O. Macchiavelli, M. A. Mcmahan, E. Rodriguez-Vieitez, F. S. Stephens, H. Ai, C. Plettner, C. W. Beausang, B. Crider

Physics Faculty Publications

We have deduced the cross section for ²³⁷U(n, f) over an equivalent neutron energy range from 0 to 20 MeV using the surrogate ratio method. A 55 MeV⁴He beam from the 88 inch cyclotron at Lawrence Berkeley National Laboratory was used to induce fission in the following reactions: ²³⁸U(α, α^f) and ²³⁶U(α, α^f). The ²³⁸U reaction was a surrogate for ²³⁷U(n, f), and the ²³⁶U reaction was used as a surrogate for ²³⁵U(n, f). Scattered α particles were detected in a fully depleted segmented silicon telescope array …

Running Coupling Constant And Transition From Low To High Energies In Quantum Chromodynamics, Alexander Babansky

Physics Theses & Dissertations

The remarkable feature of QCD is that the coupling constant (the strength of the interaction) depends on the energy of the interacting particles. At high energies, the coupling constant vanishes and QCD becomes asymptotically free. However, at lower energy, the running coupling constant increases, leading to the confining strong-coupling theory at energies of the order of hadron masses. We study the essential effects of the running coupling constant and analyze the transition from high to low energies in different processes.

Afci Quarterly Input – Unlv January 1 Through March 31, 2006, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects, activities and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

The University of Nevada, Las Vegas supports the AFCI through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support.

Efficient And Accurate Computation Of Elastic Cross Sections In The Single-Level Breit-Wigner Resonance Region, Edward L. Hobbs

Theses and Dissertations

The use of piecewise cubic Hermite polynomials to approximate resonance region cross sections provides a means to accomplish the same task with increased accuracy and fewer points that require exact cross section calculation. Once the derivative of the cross section formula is derived and the interpolating cubic is appropriately shifted and scaled for numerical stability, use of the piecewise cubic Hermite polynomial is easily inserted into computer codes that depend on cross section calculation in the resonance energy region.

Neutron Multiplicity Measurements For The Afci Program Final Quarterly Progress Report January-March 2006, Denis Beller

Transmutation Sciences Physics (TRP)

This project was developed to test a Russian-built Neutron Multiplicity Detector System (NMDS) for measuring neutrons generated in a central target by a variety of accelerators. To assist in experiment design and evaluation, we use the most advanced high-energy radiation transport code, MCNPX, to model experiments. Experimental results are compared to computational predictions and discrepancies are investigated. Initial plans were to conduct experiments using a 70-MeV proton cyclotron at the Crocker Nuclear Laboratory at the University of California at Davis and/or a 20 to 40 MeV electron linac (linear accelerator) at the Idaho Accelerator Center (IAC) at Idaho State University …

Reactor Physics Studies For The Afci Race Project: Reactor-Accelerator Coupling Experiments Project: Quarterly Progress Report January-March 2006, Denis Beller

Transmutation Sciences Physics (TRP)

In the RACE Project of the U.S. Advanced Fuel Cycle Initiative (AFCI), a series of accelerator driven subcritical systems (ADSS) experiments is being conducted at the Idaho State University’s Idaho Accelerator Center (ISU-IAC) and at the University of Texas (UT) at Austin, and will be conducted at the Texas A&M University. In these experiments electron accelerators are used to induce bremsstrahlung photon-neutron reactions in heavy-metal targets; this source of 10¹⁰ to 10¹³ n/s initiates fission reactions in the subcritical systems. These systems include a compact, transportable assembly at ISU and TRIGA reactors at UT-Austin and Texas A&M. These …

Combined Radiation Detection Methods For Assay Of Higher Actinides In Separations Processes: Quarterly Progress Report: January-March 2006, Denis Beller, Warnick Kernan

Safeguards Campaign (TRP)

Monitoring of higher actinides (HA--includes neptunium, plutonium, americium, and curium) during the separation of used nuclear fuel has been identified as a critical research area in the U.S. Advanced Fuel Cycle Initiative (AFCI). Recycling of used fuel by chemically separating it into uranium, fission products, and HA would be the first step in this new fuel cycle. The Material Protection, Accounting, and Control (MPAC) are necessary for materials accounting, criticality monitoring, and assurance of proliferation resistance. The objective of the MPAC project is to develop technology to detect and accurately measure quantities of higher actinides in used fuel assemblies and …

Dissolution, Reactor, And Environmental Behavior Of Zro2-Mgo Inert Fuel Matrix: Quarterly Report, January 2006 To March 2006, Kiel Steven Holliday, Thomas Hartmann, Kenneth Czerwinski

Fuels Campaign (TRP)

This project will examine inert matrix fuels containing ZrO₂ and MgO as the inert matrix, with the relative amount of MgO varied from 30% to 70% in ZrO₂. Reactor physics calculations will be used to examine suitable quantities of burnable poisons from the candidate elements Gd, Er, or Hf with reactor grade Pu providing the fissile component, with up to 10% of ²³⁹Pu. Ceramics will be synthesized and characterized based on the reactor physics results. The solubility of the fuel ceramics, in reactor conditions, reprocessing conditions, and repository conditions, will be investigated in a manner to …

Crystal Structure And Nano Structure Of Oxide-And Nitride Transmutation Fuel – Refinement Of Transmutation Fuel Processing For Surrogate And Radioactive Fuel Systems: Quarterly Report, January 2006 To March 2006, Chinthaka Silva

Fuels Campaign (TRP)

Transmutation-related research work at the National Laboratories, e.g. Los Alamos National Laboratory, is focused on mono-nitride ceramic fuel forms, and consists of closely coordinated “hot” actinide and “cold” inert and surrogate fuels work. Matrix and surrogate materials work involves three major components: (1) fuel matrix synthesis and fabrication, (2) fuel performance, and (3) fuel materials modeling. The synthesis and fabrication component supports basic material studies, as well as actinide fuel fabrication work through fuel fabrication process development.

This project, task 28, supports the TRP program by delivering structural data on surrogate and radioactive fuels. Crystal structure and nanostructures of the …

Characterization Of Detonation Phenomena Observed In High-Speed Visible Imagery, Trevor W. Warren

Theses and Dissertations

Measurements for radius, angular velocity, initial time of observation, and final time of observation were made for turbulent vortices around detonation fireballs. A proxy for vortex power, determined through unit analysis, was found to correlate well to initial (and final) time of observation with R² equal to 0.8572. The linear trend on a log₁₀-log₁₀ plot was indicative of a rapid decrease (over 10^-1 s) in power associated with the decay of the fireball. Predictions, based on turbulent spectral theory were made for root-mean-square velocity fluctuations and Reynolds numbers, both as functions of time. In addition, …

Synthesis And Properties Of Metallic Technetium And Technetium - Zirconium Alloys As A Radioactive Storage Waste Form To Stabilize The Technetium Waste Stream Of The Urex+1 Process, Frederic Poineau, Thomas Hartmann, Kenneth Czerwinski

Waste Forms Campaign (TRP)

In the AFCI program the UREX+1 process is proposed as one of the most promising technique to separate TRU (transuranic elements) form LWR spent nuclear fuel in the years to come. The application of UREX+1 results in good separation of the 5f-transuranics from the 4f-lanthanides, reduced waste volumes by eliminating the uranium content, and reduced waste package costs. Technetium-99 will be separated together with uranium and iodine within the first process steps. After the separation of uranium, technetium and iodine must be immobilized by their incorporation in a suitable waste storage form. Based on recent activities within the AFCI community, …

First Investigation Of Excited States In The Odd-Proton Nucleus Fr209, D. A. Meyer, C. W. Beausang, J. J. Ressler, H. Ai, H. Amro, M. Babilon, R. F. Casten, C. R. Fitzpatrick, G. Gurdal, A. Heinz, E. A. Mccutchan, C. Plettner, J. Qian, N. J. Thomas, V. Werner, E. Williams, N. V. Zamfir, Jing-Ye Zhang

Physics Faculty Publications

Excited states in ²⁰⁹Fr were produced following the ¹⁷⁶Yb(³⁷Cl, 4n) reaction. An excitation function was measured with data taken at 173, 179, and 185 MeV. Recoiling fusion-evaporation products were separated using the SASSYER gas-filled spectrometer. HPGe clover detectors of the YRAST Ball array at the target position and at the focal plane were used to detect prompt and delayed gamma ray decays, providing the first spectroscopic information about prompt and delayed transitions in ²⁰⁹Fr. The decay from a proposedπ i_13/2 configuration isomer was observed in ²⁰⁹Fr, and its half-life was measured …

Breakdown Of K Selection In 178Hf, A. B. Hayes, D. Cline, C. Wu, J. Ai, H. Amro, C. W. Beausang, R. F. Casten, J. Gerl, A. A. Hecht, A. Heinz, R. O. Hughes, R.V. F. Janssens, C. J. Lister, A. O. Macchiavelli, D. A. Meyer, E. F. Moore, P. Napiorkowski, R. C. Pardo, Ch. Schlegel, D. Seweryniak, M. W. Simon, J. Srebrny, R. Teng, K. Vetter, H. J. Wollersheim

Physics Faculty Publications

Coulomb activation of the four quasiparticle K^π = 16^{+ 178}Hf isomer (t _1/2 = 31 y) has led to the measurement of a set of Eλ matrix elements coupling the isomer band to the ground band. The present data combined with earlier ¹⁷⁸Hf Coulomb excitation data have probed the K components in the wave functions and revealed the onset and saturation of K mixing in low-K bands, whereas the mixing is negligible in the high-K bands. The implications can be applied to other quadrupole-deformed nuclei.

Next-To-Next-To-Next-To-Leading-Order Soft-Gluon Corrections In Hard-Scattering Processes Near Threshold, Nikolaos Kidonakis

Faculty and Research Publications

I present a unified calculation of soft-gluon corrections to hard-scattering cross sections through next-to-next-to-next-to-leading order (NNNLO). Master formulas are derived, from a threshold resummation formalism, that can be applied to total and differential cross sections for hard-scattering processes in hadron colliders. I also present numerical results for charged Higgs production at the LHC where these corrections are large, and for top quark production at the Tevatron where these corrections greatly reduce the scale dependence of the cross section.

Neutron Multiplicity Measurements Of Target/Blanket Materials, Denis Beller

Transmutation Sciences Physics (TRP)

The U.S. Advanced Fuel Cycle Initiative (AFCI) is a program to develop economic and environmental methods to reduce the impact of waste from commercial nuclear fuel cycles. One concept for near-complete destruction of waste isotopes from used nuclear fuel is accelerator-driven transmutation. High-power accelerators would be used to produce high-energy charged particles, which then collide with heavy metal targets to create a cascade of neutrons. These neutrons then cause nuclear reactions in subcritical systems.

To design these systems, complex reactor physics computer codes and highly detailed data libraries are used to compute the reactivity of systems, reaction rates, destruction rates, …

Development Of Dose Coefficients For Radionuclides Produced In Spallation Targets, Phillip W. Patton, Mark Rudin

Transmutation Sciences Physics (TRP)

Dose coefficients permit simple determination of radiation dose associated with various exposure scenarios, and ultimately permit radiation safety personnel to assess the health risks to workers in a nuclear facility. Specifically, radiation safety personnel use dose coefficients to determine the radiation dose incurred to a tissue or organ system from a given exposure. These parameters are often expressed in terms of Annual Limits on Intake (ALIs) and Derived Air Concentrations (DACs).

The research consortium comprised of representatives from several universities and national laboratories has successfully generated internal and external dose conversion coefficients for twenty radionuclides produced in spallation neutron sources. …

Reactor Physics Studies For The Afci Reactor-Accelerator Coupling Experiments (Race) Project, Denis Beller

Transmutation Sciences Physics (TRP)

The specific research objective of this three-year project is to design and conduct an accelerator driven experiment. This experiment will help demonstrate in the U.S. the ability to design, compute, and conduct ADSS experiments; and to predict and measure source importance, coupling efficiency, sub-critical reactor kinetics and source-driven transients. In addition, databases will be created for both steady state and transient ADSS experiments for the nuclear community to develop and test new computational codes and methods, and the importance of a driving neutron source in various regions of different subcritical assemblies will be mapped. Experiments will be conducted and compared …

Investigation Of Optical Spectroscopy Techniques For On-Line Materials Accountability In The Solvent Extraction Process, Gary Cerefice, Kenneth Czerwinski

Safeguards Campaign (TRP)

The long-term goal of this project is the evaluation of optical spectroscopy-based techniques for the on-line, real-time determination of actinide element concentrations in fuel recycling plant process streams. To generate the information necessary to evaluate the potential of these systems, initial experiments will focus on determining the detection limits for UV/Vis and LFS will be measured for the actinide elements under chemical conditions representative of the process streams for the UREX+ process. The system will then be systematically explored to examine the impact of acid concentration, nitrate concentration, redox potential, diluent concentration, ligand concentration, and contaminant/ fission product concentration on …

Optical Spectroscopy: Quarterly Report: 01/01/06 – 03/31/06, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Safeguards Campaign (TRP)

Progress report for the quarter: laser system alignment finished, site visit scheduled for final spectrometer configuration; initial studies on UO2 2+/NO3 -/H+ completed; preliminary data regression in progress; preliminary work on uranyl/AHA and organic/aqueous interface systems started.

Combined Radiation Detection Methods For Assay Of Higher Actinides In Separation Processes (Afci), Denis Beller, Warnick Kernan

Safeguards Campaign (TRP)

The ultimate objective of this project is to develop technology to detect and accurately measure quantities of higher actinides in processing systems without taking frequent samples. These systems include used fuel receipt, separations batches, and pipelines. A variety of measurements may be combined to calculate flow rates of actinide elements with a to-be-determined precision. Nuclear and decay characteristics of materials during processing will be acquired, conceptual designs of monitoring systems will be developed, radiation transport studies will be conducted to develop an understanding of operational regimes, and experiments will be performed to confirm performance. Radiation transport and scoping studies will …