Coupled 100-group neutron and 21-group gamma-ray cross sections for EPR calculations

Plaster, D.M.; Santoro, R.T.; Ford, William E.

doi:10.2172/4208056

Cited by 24 publications

(13 citation statements)

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“…A radial interval size of about 2% of the meteorite's radius gave essentially the same results that finer intervals did. The neutron energy interval or group structure used in ANISN is the GAM II structure [Joanou and Dudek, 1963] to take advantage of the extensive EPR-DLC37 [Plaster et aL, 1975]…”

Section: Neutron-source Energy Dependencementioning

confidence: 99%

Cosmogenic neutron‐capture‐produced nuclides in stony meteorites

et al. 1986

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The distribution of neutrons with energies below 15 MeV in spherical stony meteoroids is calculated using the ANISN neutron‐transport code. The source distributions and intensities of neutrons are calculated using cross sections for the production of tritium. The meteoroid's radius and chemical composition strongly influence the total neutron flux and the neutron energy spectrum, whereas the location within a meteoroid only affects the relative neutron intensities. Meteoroids must have radii of more than 50 g/cm2 before they have appreciable fluxes of neutrons near thermal energies. Meteoroids with high hydrogen or low iron contents can thermalize neutrons better than chondrites can. Rates for the production of 60Co, 59Ni, and 36Cl are calculated with these neutron fluxes and evaluated neutron‐capture cross sections and are reported for carbonaceous chondrites with high hydrogen contents, L‐chondrites, and aubrites. For most meteoroids with radii <300 g/cm2, the production rates of these neutron‐capture nuclides increase monotonically with depth. The highest calculated 60Co production rate in an ordinary chondrite is 375 atoms/min/g‐Co at the center of a meteoroid with a 250 g/cm2 radius. The production rates calculated for spallogenic 60Co and 59Ni are greater than the neutron‐capture rates for radii less than ∼50–75 g/cm2. Only for very large meteorpids and chlorine‐rich samples is the neutron‐capture production of 36Cl important. The results of these calculations are compared with those of previous calculations and with measured activities in many meteorites.

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Section: Neutron-source Energy Dependencementioning

confidence: 99%

Cosmogenic neutron‐capture‐produced nuclides in stony meteorites

et al. 1986

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“…11 Correlations between the errors in I:x and all other cross sectiohs 11 is an appreciable part of the tota1 variance, then one may conclude that the errors and error correlations in this partial cross section contribu.te significantly to the standard deviation.…”

Section: Xmentioning

confidence: 97%

“…The transport calculations were carried out with the discrete ordinates code ANISN [10], using a P 3 scattering expansion and an S 12 quadrature, and the coupled neutron-gamma-ray cross-section library of Plaster, Santoro, and Ford [11].…”

Section: Geometry and Details Of The Calculationsmentioning

confidence: 99%

“…The standard deviation is the quantity of most interest since it reflects the errors and the error correlations in·all of the cross sections, but some information on the importance of the errors and error correlations _in a particular partial cross section may be obtained by considering the individual contributions to the· variance ·given in Tables IV and V. If, for example, for a particular partial cross section, x, the algebraic sum of the contributions to the variance from 11 Errors 'in E II and .…”

Section: Uncertainties In the Calculated Responses Due To Cross-sectimentioning

confidence: 99%

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Uncertainties in Calculated Heating and Radiation Damage in the Toroidal Field Coil of a Tokamak Experimental Power Reactor Due to Neutron Cross-Section Errors

1977

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“…In the first calculation the test cell with no injector present was considered, and in the second calculation the test cell with an injector present was considered, but in this calculation the radiation sources were the activation photons produced by neutrons that stream through the penetration in.the igloo and the activation photons produced inside the igloo that stream through the penetration in the igloo. The first calculation 11 With no injector 11 was carried out assuming cylindrical symmetry about the test cell vertical axis as indicated in Fig. 1.…”

mentioning

confidence: 99%