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Brolley, J.E.; Fowler, J.L.; Schlacks, L.K.

doi:10.1103/physrev.88.618

Cited by 73 publications

(18 citation statements)

References 17 publications

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“…The measured data for the ratio essentially confirm the estimates by the two approaches. In all, this indicates that the measurements of Bormann et al [81] and Brolley et al [82] for the total (n, 2n) cross sections are too high.…”

Section: The (N 2n) Reactionsmentioning

confidence: 73%

Reaction mechanisms of fast neutrons on stable Mo isotopes below 21 MeV

et al. 2005

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A large number of new measurements with the activation technique were performed for (n,2n) and neutron-induced Z = 1,2 reaction cross sections on the stable molybdenum isotopes in the energy range from 13.5 to 21 MeV. First results were obtained for the 92 Mo(n,2n) Mo(n,x) 97 Nb m , and 100 Mo(n,α) 97 Zr reactions, above 16 MeV. A significant number of high-accuracy 14 MeV measurements were performed which are in good agreement with the measurements above 16 MeV for reactions studied in both energy ranges. The rather complete database for the molybdenum isotopes was analyzed with two different sets of consistent model calculations: a local and a global approach. The global approach (a blind calculation with the TALYS code) provides a good overall description of the dominant reaction channels, although the (n,α) reactions for the heavy isotopes are overpredicted. The local approach (an adjusted calculation with the STAPRE-H code) describes the shapes and magnitudes of the excitation functions well from the reaction thresholds up to 21 MeV using a consistent parameter set, which was optimized based on all experimental information for the nuclei at hand and their immediate neighbors. The agreement between experimental and calculated data is, in general, good both at the maxima and at the tails of the excitation functions, and both for total activation cross sections of a particular channel and for cross sections leading to isomers, showing the viability of the level densities, the optical models, and the γ widths. Comparison of the two model calculations with the data indicates the relevance of an appropriate treatment for preequilibrium (PE) α-particle emission for the description of the data above 14 MeV. Comparison between the model calculations shows largely different PE deuteron emission contributions to the total ( Z = 1, A = 1) cross sections with an additional marked difference in energy dependence. This suggests that emission spectra around 20 MeV are required to establish the magnitude of the PE deuteron emission contribution to this process. New γ -ray strength functions were established by verification against average (n,γ ) data and were demonstrated to give good agreement with the measured isomer production cross sections.

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Section: The (N 2n) Reactionsmentioning

confidence: 73%

Reaction mechanisms of fast neutrons on stable Mo isotopes below 21 MeV

et al. 2005

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“…There are a number of measurements below 34 MeV [lll, 112,113,1151 in addition to the (old) measurement at 90 MeV by Mcmillan and York [114]. Our calculated cross section is approximately two times smaller than these measurements.…”

Section: 32mentioning

confidence: 52%

“…The various experimental measurements are fairly consistent with each other, and our calculations describe them well. E, (MeV) Figure 29: Calculated (n, 2n) cross section compared to experimental measurements [lll, 112,113,1141 Kerma Factors 75 8 …”

Section: Comparison With (N 12') Measurementsmentioning

confidence: 99%

Evaluated cross-section libraries and kerma factors for neutrons up to 100 MeV on {sup 12}C

Chadwick¹,

Blann²,

Cox³

et al. 1995

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DIscLAlMERThis document was pwpared s an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the UNversity of California nor any of their employees, makes any warranty, expres or implied, or aseumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference Abstract A program is being carried out at Lawrence Livermore National Laboratory to develop high-energy evaluated nuclear data libraries for use in Monte Carlo simulations of cancer radiation therapy. In this report we describe evaluated cross sections and kerma factors for neutrons with incident energies up to 100 MeV on 12C; in subsequent reports we shall describe our high-energy libraries for neutrons on I4N, l60, 31P and 40Ca, as well as accelerator collimator and shielding materials. The aim of this effort is to incorporate advanced nuclear physics modeling methods, with new experimental measurements, to generate cross section libraries needed for an accurate simulation of dose deposition in fast neutron therapy.The evaluated libraries are based mainly on nuclear model calculations, benchmarked to experimental measurements where they exist. We use the GNASH code system, which includes Hauser-Feshbach, preequilibrium, and direct reaction mechanisms. The libraries tabulate elastic and nonelastic cross sections, angle-energy correlated production spectra for light ejectiles with A54, and kinetic energies given to light ejectiles and heavy recoil fragments. The major steps involved in this effort are: (1) development and validation of nuclear models for incident energies up to 100 MeV; (2) collation of experimental measurements, including new results from Louvain-la-Nueve and Los Alamos; (3) extension of the Livermore ENDL formats for representing highenergy data; (4) calculation and evaluation of nuclear data; and (5) validation of the libraries. We describe the evaluations in detail, with particu1a.r emphasis on our new high-energy modeling developments. Our evaluations agree well with experimental measurements of integrated and differential cross sections. We compare our results with the recent ENDF/B-VI cvaluatioii which extends up to 32 MeV. We also compare kerma factors resulting from our evaluated microscopic cross sections with measurements, providing an important integral benchmarking of the libraries. The evaluated libraries are described and illustrated in detail. bmJBVnON OF MIS.. Contents AbstractA program is being carried out at Lawrence Livermore National Laboratory to develop high-energy evaluated nuclear data libraries for use in Monte Carlo simulations of cancer radiation therapy. In this report we describe evaluated cross sections and kerma factors for neutrons with incident energies up to 100 MeV on 12C; in subsequent reports we shall describe our high-energy libraries for neutrons on I4N, l60, 31P and 40Ca, ...

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“…NaCl was precipitated by the addition of w-butanol which had been saturated with HC1 gas. 5 The NaCl precipitate was filtered onto a tared No. 50 Whatman Filter circle (f-in.…”

Section: (C) Preparation Of Na 22 Samples For Countingmentioning

confidence: 99%

(n, 2n) Cross Section ofNa23at 14.1 Mev

Prestwood

1955

Phys. Rev.

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An experimental determination of this cross section was made on six individual samples and involved the use of 47r counting, low background counting, neutron monitoring, and sample thickness corrections. The value obtained is 13.8±2.2 millibarns and the error quoted is twice the standard deviation obtained from the six samples. The experimental work is described in detail and a discussion of the possible errors is given.

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(n,2n) Reactions inC12,

Cited by 73 publications

References 17 publications

Reaction mechanisms of fast neutrons on stable Mo isotopes below 21 MeV

Reaction mechanisms of fast neutrons on stable Mo isotopes below 21 MeV

Evaluated cross-section libraries and kerma factors for neutrons up to 100 MeV on {sup 12}C

(n, 2n) Cross Section ofNa23at 14.1 Mev

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