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Neutron Nonelastic Cross-Section Measurements from 7 to 29 Mev

Description: Abstract: "Neutron nonelastic cross sections have been measured for 23 elements at 14 Mev, and for a selected set of these elements over the energy ranges 7 to 14 Mev and 21 to 29 Mev. Conventional sphere transmission techniques were used for the measurements. A comparison with optical model calculations of Bjorklund and Fernbach shows excellent agreement."
Date: May 19, 1958
Creator: MacGregor, Malcolm H.
Partner: UNT Libraries Government Documents Department

Total Neutron Cross Section for Uranium from 20 Kev to 20 Mev

Description: Abstract: "The total neutron cross section of normal uranium has been measured for neutron energies from 20 kev to 7.6 Mev and at 17, 19 and 20 Mev. When combined with other published work in the 7-14 Mev range, the result is a smooth cross section curve up to 20 Mev. The curve fits smoothly on the surface showing total neutron cross section as a function of both atomic weight and neutron energy."
Date: 1953
Creator: Henkel, R. L.; Cranberg, L.; Jarvis, G. A.; Nobles, R. & Perry, J. E.
Partner: UNT Libraries Government Documents Department

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

Tables of Neutron Cross Sections

Description: Report presenting data tables which summarize neutron cross sections for elements from hydrogen to bismuth. This data was to be available on September 1, 1947. Purpose and acknowledgements are given as well as criteria for omitting measurements and explanation of the material.
Date: October 28, 1947
Creator: Way, Katharine & Haines, G.
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


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


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


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