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Triple Differential Cross sections and Nuclear Recoil in Two-Photon Double Ionization of Helium

Description: Triple differential cross sections (TDCS) for two-photon double ionization of helium are calculated using the method of exterior complex scaling both above and below the threshold for sequential ionization (54.4 eV). It is found that sequential ionization produces characteristic behavior in the TDCS that identifies that process when it is in competition with nonsequential ionization. Moreover we see the signature in the TDCS and nuclear recoil cross sections of"virtual sequential ionization" below the threshold for the sequential process.
Date: April 29, 2008
Creator: Horner, Daniel A.; McCurdy, C. William & Rescigno, Thomas N
Partner: UNT Libraries Government Documents Department

Thermal-neutron capture for A=26-35

Description: The prompt gamma-ray data of thermal- neutron captures fornuclear mass number A=26-35 had been evaluated and published in "ATOMICDATA AND NUCLEAR DATA TABLES, 26, 511 (1981)". Since that time themanyexperimental data of the thermal-neutron captures have been measuredand published. The update of the evaluated prompt gamma-ray data is verynecessary for use in PGAA of high-resolution analytical prompt gamma-rayspectroscopy. Besides, the evaluation is also very needed in theEvaluated Nuclear Structure Data File, ENSDF, because there are no promptgamma-ray data in ENSDF. The levels, prompt gamma-rays and decay schemesof thermal-neutron captures for nuclides (26Mg, 27Al, 28Si, 29Si, 30Si,31P, 32S, 33S, 34S, and 35Cl) with nuclear mass number A=26-35 have beenevaluated on the basis of all experimental data. The normalizationfactors, from which absolute prompt gamma-ray intensity can be obtained,and necessary comments are given in the text. The ENSDF format has beenadopted in this evaluation. The physical check (intensity balance andenergy balance) of evaluated thermal-neutron capture data has been done.The evaluated data have been put into Evaluated Nuclear Structure DataFile, ENSDF. This evaluation may be considered as an update of the promptgamma-ray from thermal-neutron capture data tables as published in"ATOMIC DATA AND NUCLEAR DATA TABLES, 26, 511 (1981)".
Date: June 1, 2001
Creator: Chunmei, Z. & Firestone, R.B.
Partner: UNT Libraries Government Documents Department

Pre-Processing of Cross-Sections Using Dimensionality Reduction Techniques

Description: Reactor physics codes rely on cross-section data to determine, for example, flux profiles or burn-up calculations. This data contains cross section values for different neutron-atom interactions (e.g., absorption, fission and scattering) for a large number of isotopes as function of energy and it is tabulated for a specific set of parameters (e.g., moderator temperature, fuel temperature, moderator density). In order to perform such neutronic calculations, the amount of this data that needs to be stored is very large due to the high number of isotopes and many tabulation points are needed. This data needs to be retrieved at each time iteration of the code from the machine memory which negatively affects the computational time of the code itself.
Date: November 1, 2012
Creator: Mandelli, D.; Rabiti, C. & Alfonsi, A.
Partner: UNT Libraries Government Documents Department

L- and M-Shell X-Ray Production Cross Sections of Neodymium Gadolinium, Holmium, Ytterbium, Gold and Lead by 25-MeV Carbon and 32-MeV Oxygen Ions

Description: L- and M-shell x-ray production cross sections have been measured for thin solid targets of neodymium, gadolinium, holmium, ytterbium, gold, and lead by 25 MeV 12/6C^q+ (q=4,5,6) and by 32 MeV 16/8O^q+ (q=5,7,8). The cross sections were determined from measurements made with thin targets (< 2.5 μg/cm2). For projectiles with one or two K-shell vacancies, the target x-ray production cross sections were found to be enhanced over those for projectiles without a K-shell vacancy. The sum of direct ionization to the continuum (DI) plus electron capture (EC) to the L, M, N... shells and EC to the K-shell of the projectile have been extracted from the data. The results are compared to the predictions of first Born theories, i.e., plane wave Born approximation for DI and Oppenheimer-Brinkman-Kramers formula of Nikolaev for EC and to the ECPSSR approach that accounts for Energy loss and Coulomb deflection of the projectile as well as for Relativistic and Perturbed Stationary States of inner shell electrons.
Date: August 1987
Creator: Andrews, Mike C., 1949-
Partner: UNT Libraries

Force and pressure measurements at transonic speeds for several bodies having elliptical cross sections

Description: Report presenting the measured force characteristics and surface-pressure distributions at a range of angles of attack for a series of bodies with elliptical cross sections. Results regarding pressure data and force data are provided.
Date: September 1958
Creator: McDevitt, John B. & Taylor, Robert A.
Partner: UNT Libraries Government Documents Department

Application of exterior complex scaling to positron-hydrogencollisions including rearrangement

Description: The first application of an exterior complex scaling method to an atomic scattering problem with distinct rearrangement channels is reported. Calculations are performed for positron-hydrogen collisions in an s-wave model employing an electron-positron potential of V{sub 12} = -(8+(r{sub 1}-r{sub 2}){sup 2}){sup 1/2}, using the time-independent propagating exterior complex scaling (PECS) method. This potential has the correct long-range Coulomb tail of the full problem and the results demonstrate that ECS-based methods can accurately calculate scattering, ionization and positronium formation cross sections in this three-body rearrangement collision.
Date: December 6, 2007
Creator: Bartlett, Philip L.; Stelbovics, Andris T.; Rescigno, Thomas N. & McCurdy, C. William
Partner: UNT Libraries Government Documents Department

TABLE OF NUCLIDES

Description: This table presents properties of nuclides, both stable and radioactive, adopted from the 7th edition of the Table of Isotopes. The data are based on experimental results reported in the literature, with the cutoff date varying from January to December, 1977. (The earliest date refers to the lightest nuclides, and vice versa.) Most mass excesses are from the 1977 Atomic Mass Evaluation, with some recent experimental values added. For a few of the very unstable nuclides for which no values were reported in the 1977 Atomic Mass Evaluation, estimates are taken from the tables of W.D. Myers. Natural isotopic abundances and neutron cross sections are taken from compilations by N.E. Holden. For other references, original data, and information on the data measurements, the reader is referred to reference 1.
Date: January 1, 1980
Creator: Shirley, V.S. & Lederer, CM.
Partner: UNT Libraries Government Documents Department

The Formation of U232 by Helium Ions of Thorium

Description: The production of U{sup 232} by the sum of {alpha},4n and {alpha},p 3n reactions on thorium has been studied. The cross section at an average energy of 37.5 Mev was 0.013 barns and the threshold for the reaction was about 30 Mev.
Date: April 14, 1948
Creator: Newton, Amos S.
Partner: UNT Libraries Government Documents Department

ISOTOPE PRODUCTION CROSS SECTIONS FROM THE FRAGMENTATION OF 16O AND 12C AT RELATIVISTIC ENERGIES

Description: The 0-degree fragmentation products of {sup 16}O and {sup 12}C at 2.1-GeV/n and {sup 12}C at 1.05-GeV/n have been measured for targets ranging from H to Pb. They present a total of 464 partial-production cross sections for 35 isotopes. The cross sections are energy independent and can be factored into beam-fragment and target terms. The target factor, {gamma}{sub T} = A{sub T}{sup 1/4}, and other evidence, imply the isotopes are produced in peripheral interactions.
Date: February 1, 1975
Creator: Lindstrom, P.J.; Greiner, D.E.; Heckman, H.H.; Cork, Bruce & Bieser, F.S.
Partner: UNT Libraries Government Documents Department

PARTICIPANT INTIMACY - A CLUSTER ANALYSIS OF THE INTRANUCLEAR CASCADE

Description: The intranuclear cascade for relativistic nuclear collisions is analyzed in terms of 'clusters' consisting of groups of nucleons which are dynamically linked to each other by violent interactions. The formation cross sections for the different cluster types as well as their intrinsic dynamics are studied and compared with the predictions of the linear cascade model ('rows-on-rows').
Date: August 1, 1980
Creator: Cugnon, J.; Knoll, J. & Randrup, J.
Partner: UNT Libraries Government Documents Department

The Scattering of Positrons by Atomic Hydrogen: Formulation

Description: The derivation of the coupled systems of second-order integrodifferential equations which must be solved numerically in order to obtain the cross sections for the elastic and inelastic scattering of positrons by atomic hydrogen and the cross sections for the formation of positronium into the 1s and 2s states is considered. The numerical method to be used to solve the equations at incident energies above excitation thresholds is also discussed. (auth)
Date: October 1, 1960
Creator: Cody, W. J. & Smith, K.
Partner: UNT Libraries Government Documents Department

Parabolic-Trough Technology Roadmap: A Pathway for Sustained Commercial Development and Deployment of Parabolic-Trough Technology

Description: Technology roadmapping is a needs-driven technology planning process to help identify, select, and develop technology alternatives to satisfy a set of market needs. The DOE's Office of Power Technologies' Concentrating Solar Power (CSP) Program recently sponsored a technology roadmapping workshop for parabolic trough technology. The workshop was attended by an impressive cross section of industry and research experts. The goals of the workshop were to evaluate the market potential for trough power projects, develop a better understanding of the current state of the technology, and to develop a conceptual plan for advancing the state of parabolic trough technology. This report documents and extends the roadmap that was conceptually developed during the workshop.
Date: January 31, 1999
Creator: Price, H. & Kearney, D.
Partner: UNT Libraries Government Documents Department

Recent measurements of neutron total cross sections on a wide range of targets from 5 to 600 MeV at LANSCE/WNR

Description: We have completed a new set of total cross section measurements, snd have measured approximately 36 additional samples. The goal of the new measurements was 1% statistical accuracy in 1% energy bins with systematic errors less than 1%. This was achieved for all but the smallest samples, for which the statistical accuracy was as large as 2% in 1% bins. However, the energy resolution is significantly better than this at low energies. The samples were: * The APT spallation target material: W * Medium-mass stmctural materials: Ti, V, Cr, Mn, Fe, Co, Ni * Actinides: Th, depleted U * Other materials for global optical model development: F, Mg, P, S, K, Y, Mo, In, Au, Hg, natural Pb * Separated isotopes of light nuclei: {sup 6}Li%, {sup 7}Li, {sup 10}B, {sup 11}B, {sup 13}C, * Medium- and heavy-mass separated isotopes: {sup 54,56}Fe, {sup 182,183,184,186}W * Few-nucleon physics: H, D.
Date: May 1, 1997
Creator: Dietrich, F.S.; Abfalterer, W.P.; Haight, R.C.; Morgan, G.L.; Bateman, F.B. & Finlay, R.W.
Partner: UNT Libraries Government Documents Department

Two-photon double ionization of H2 at 30 eV using Exterior Complex Scaling

Description: Calculations of fully differential cross sections for two-photon double ionization of the hydrogen molecule with photons of 30 eV are reported. The results have been obtained by using the method of exterior complex scaling, which allows one to construct essentially exact wave functions that describe thedouble continuum on a large, but finite, volume. The calculated cross sections are compared with those previously obtained by Colgan et al., and discrepancies are found for specific molecular orientations and electron ejection directions.
Date: January 20, 2009
Creator: Morales, Felipe; Martin, Fernando; Horner, Daniel; Rescigno, Thomas N. & McCurdy, C. William
Partner: UNT Libraries Government Documents Department

Summary Report: First Research Coordination Meeting on ReferenceDatabase for Neutron Activation Analysis

Description: Potential problems associated with nuclear data for neutronactivation analysis were identified, the scope of the work to beundertaken was defined together with its priorities, and tasks wereassigned to participants. Data testing and measurements refer to gammaspectrum peak evaluations, detector efficiency calibration, neutronspectrum characteristics and reference materials analysis.
Date: October 31, 2005
Creator: Firestone, Richard B. & Trkov, Andrej
Partner: UNT Libraries Government Documents Department

Longitudinal double-spin asymmetry and cross section for inclusivejet production in polarized proton collisions at sqrt(s) = 200 GeV

Description: We report a measurement of the longitudinal double-spinasymmetry A_LL and the differential cross section for inclusivemidrapidity jet production in polarized proton collisions at sqrt(s)=200GeV. The cross section data cover transverse momenta 5<pT<50GeV/c and agree with next-to-leading order perturbative QCD evaluations.The A_LL data cover 5<pT<17 GeV/c and disfavor at 98 percentC.L. maximal positive gluon polarization in the polarizednucleon.
Date: August 10, 2006
Creator: Abelev, B.I.; Adams, J.; Aggarwal, M.M.; Ahammed, Z.; Amonett,J.; Anderson, B.D. et al.
Partner: UNT Libraries Government Documents Department