Browsing by Author "Doherty, G"

Now showing 1 - 15 of 15
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    AAEC nuclear data card library
    (Australian Atomic Energy Commission, 1964-03) Doherty, G
    This report describes the compilation of the A.A.E.C. nuclear data card library and the conventions relating to the use of the data in neutronics calculations. Details of data processing programmes, library formats, and the extent of the information available for each nuclide are given in the appendices.
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    Anisotropic collision probabilities for one dimensional geometries
    (Australian Atomic Energy Commission, 1971-07) Doherty, G
    The equations for Po and P1 collision properties in slab, spherical and cylindrical geometries are presented. A method of solution of the resulting multigroup neutron flux equation is discussed. The extension of Sn codes to incorporate anisotropic scattering is straightforward and the time penalty incurred in the calculation probability method is difficult and doubling the length of the flux vector increases the solution time dramatically. It is therefore concluded that the Sn method will be superior for most anisotropic calculations.
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    Calculated K, L, and M shell X-ray line intensities for light ion impact on selected targets from Z=6 to 100
    (Australian Nuclear Science and Technology Organisation, 2011-09-01) Crawford, J; Cohen, DD; Doherty, G; Atanacio, AJ
    A computer code to calculate the K, L, and M α, β and γ X-ray line intensities, KLMabgRatios, is described together with the input tables used to calculate these intensities for light ion bombardment of targets with atomic numbers from Z=6 to 100. The KLMabgRatios program was written with the main aim of updating the 1980’s data files used up till now (Clayton AAEC M113/1986), with more recent experimental and theoretical datasets published in the last 2 years or so. Preferred recommended K, L and M X-ray line intensities for light ion impact on selected targets for atomic numbers between Z=6 and 100 are given for 8 K lines, 17 L lines and 22 M lines as well as their corresponding ωK, ωL and ωM total shell fluorescence yields. In addition a program, wexplore, has been written to carry out Gaussian fits to experimental K, L and M X-ray spectra to better determine L and M X-ray production subshell cross sections for light ion bombardment. A section on the use of this wexplore program is also included in this report.
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    Collision probability calculations in cluster geometry
    (Australian Atomic Energy Commission, 1970-03) Doherty, G
    Four methods for the calculation of multigroup collision probabilities in cluster geometry are described these are Monte Carlo, full numerical integration, numerical integration over the annuli containing rods combined with the Bonalumi approximation in the moderator annuli, and a ring smearing method again based on the Bonalumi approximation for annular geometry. Results of six group calculations for three tight, natural uranium, D20 lattices are presented in detail. These results suggest that the ring smearing model is suitable for cluster calculations which do not require high accuracy the largest error is in the thermal flux in the outer moderator regions. This error is a general problem inherent in the Bonalumi approximation and is not peculiar to the ring smearing model presented.
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    Collision probability calculations including axial leakage
    (Australian Atomic Energy Commission, 1971-03) Doherty, G
    Equations are presented for the calculation of collision probabilities in cylindrical geometry with axial leakage included through a complex cross section term. Numerical results are presented for two single rod, natural uranium heavy water reactor lattices. Similar calculations may be performed with modified Sn programmes and the author concludes that these are more efficient.
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    Comparison of proton and helium induced M subshell X-ray production cross sections with the ECUSAR theory
    (Elsevier, 2014-01-01) Cohen, DD; Stelcer, E; Atanacio, AJ; Crawford, J; Doherty, G; Lapicki, G
    M subshell X-ray production cross sections have been measured for Mα12, Mβ1, Mγ, M2–N4 and M1–O23 transitions representing all five M subshells. These experimental cross sections have been compared with the ECUSAR theory of Lapicki and four parameter fits are given to the experiment to theory ratios covering the proton and helium ion energy range from 0.5 to 3 MeV on thin W, Au, Pb, Th and U targets.© 2013 Elsevier B.V.
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    Key experimental M subshell line x-ray production cross sections for slow light ions on high atomic number targets compared with the ECUSAR theory
    (Federal University of Rio Grande do Sul (UFRGS), 2013-07-01) Cohen, DD; Stelcer, E; Crawford, J; Atanacio, AJ; Doherty, G; Lapicki, K
    The x-ray production cross sections for dominant lines in each of the five M subshells have been measured for slow proton and helium ion impact on selected high atomic number targets from tungsten to uranium. Proton energies between 0.5 and 3 MeV and helium ion energies between 0.5 and 2 MeV were used providing M subshell cross sections for 0.3 < x < 3, where x = v /(q v ), as defined by Brandt and Mi s 1 s 2s Lapicki 1979, distinguishes between slow (x < 1) and fast (x > 1) collision regimes. s s Ion energies and targets over these ranges cover the commonly used PIXE range for M subshell x-ray production on heavy targets across the x-ray energy range 1.3-6 keV, which has a strong overlap with key common K shell elements from Al to Fe. Hence it is important for frequently used PIXE analysis programs like GUPIX and GEOPIXE to have a consistent set of M subshell cross sections together with subshell parameters, like fluorescence yields and Coster-Kronig transition rates, which will precisely and accurately predict M shell line intensities over this low energy X-ray region of interest.
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    Matrices and numerical solution of linear equations. Reactor physics, mathematics and computers summer school for teachers.
    (Australian Atomic Energy Commission, 1972-12) Doherty, G
    Matrices and numerical solution of linear equations are introduced through a simple model of a neutron life cycle in a nuclear reactor.
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    Matrices and numerical solution of linear equations. Reactor physics, mathematics and computers summer school, January 1972.
    (Australian Atomic Energy Commision, 1972-01) Doherty, G
    Matrices and numerical solution of linear equations are introduced through a simple model of a neutron life cycle in a nuclear reactor.
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    MCRP - a Monte Carlo resonance program for neutrons slowing down in single rod and rod cluster lattices.
    (Australian Atomic Energy commission, 1985-09) Doherty, G; Robinson, GS
    MCRP is a Monte Carlo computer program for tracking neutrons slowing down in single rod and rod cluster lattices. The code is intended for calculations of resonance absorption in reactor fuel nuclides using cross sections at 124 000 energy points below 20 keV. The only intrinsic assumptions are that scattering is both elastic and isotropic in the centre of mass system.
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    MULGA - a complex of codes for the determination of multigroup averaged neutron cross section data
    (Australian Atomic Energy Commission, 1963-12) Clancy, BE; Doherty, G; Keane, A; Kletzmayr, EK; Pollard, JP
    A complex of computer programmes called MULGA is described which will produce multigroup cross sections in a format suitable for input into a selection of reactor codes. Always bearing in mind that the spatial variation of flux will frustrate any determination of "exact" cross sections the maximum accuracy has been striven for within the limitations of urgency and feasibility. The programmes; together with an associated microscopic data library tape, and a specialised monitor system, have been coded for an IBM 1620 computer with 4 magnetic tapes. The basic programmes MULGA 1 and MULGA 2 have already been adapted for an ISM 7090 and the whole series will be modified for the new site computer in 1964.
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    Solution of some problems by collision probability methods
    (Australian Atomic Energy Commission, 1969-07) Doherty, G
    A comparison is made between isotropic collision probability and discrete Sn solutions to some one-dimensional neutron transport problems. Difficulties associated with the application of one or the other method in particular situations are discussed in detail. The Sn method is generally superior in cylindrical and spherical geometries and the collision probability method is recommended for slab geometry.
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    Solution of the multigroup collision probability equations
    (Australian Atomic Energy Commission, 1969-04) Doherty, G
    A method is presented for the solution of the multigroup collision probability equations arising in reactor physics calculations. The method is a block relaxation scheme, involving the direct solution by inversion of the equations for a single group, and it has the conceptual advantage over the successive over-relaxation method that problems without upscatter, which are of interest in fast reactor design, can be solved without inner iteration.
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    Some iterative methods for solving the matrix equation Ax = b
    (Australian Atomic Energy Commission, 1968-10) Doherty, G
    This paper reviews the salient features of a number of iterative methods for solving the matrix equation Ax = b, and includes a brief description of the calling sequences to Fortran subroutines written for the IBM 360/50 with an assessment of the computational efficiency of the different methods for low order full matrices. Some attention is given to the question of acceleration and the necessity for double precision arithmetic.
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    ZHEX - a three dimensional diffusion code for hexagonal, z geometry
    (Australian Atomic Energy Commission, 1974-03) Doherty, G
    A description is given of ZHEX, a multigroup, finite difference diffusion code for hexagonal-z geometry. The code was written for an IBM360/50 run in MVT mode using HASP and employs dynamic storage allocation, direct access data sets and some double precision arithmetic. The basic calculation block contains one plane of mesh points for one group so that core storage requirements are independent of the numbers of groups and axial planes. With the present overlay structure a 250 MW fast reactor requires 246K and a 1,000 MW fast reactor 342K. Calculation times are given for some realistic sample problems.