A systematic investigation of reaction cross sections and isomer ratios for neutrons up to 20 MeV on Ni-isotopes and 59Co by measurements with the activation technique and new model studies of the underlying reaction mechanisms

Semkova, V.; Avrigeanu, V.; Glodariu, T.; Koning, A. J.; Plompen, A.; Smith, Donald L.; Sudár, S.

doi:10.1016/j.nuclphysa.2003.11.005

Cited by 57 publications

(85 citation statements)

References 45 publications

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“…These calculations will be referred to as global approach or TALYS calculations, interchangeably. The second set of calculations concerns models used previously for the analysis of the target nucleus 51 V [6,13], the isotopes of nickel and 59 Co [31] by means of the computer codes DWUCK4 [32], and the updated version of STAPRE-H95 [33]. Here too, a consistent set of parameters is used for each nucleus that is involved in the calculations.…”

Section: Nuclear Model Calculationsmentioning

confidence: 99%

“…[31] for Ni isotopes 044617-4 TABLE III. Measured activation cross sections (mb) for Mo isotopes between 13.5 and 14.8 MeV.…”

Section: A Global Approachmentioning

confidence: 99%

“…However, a new version (0.59) of the TALYS code [30] was used, although the description given in Ref. [31] regarding the choices for the optical model [34,35], the direct reaction (distorted-wave Born approximation, DWBA, using ECIS97 [36]), the preequilibrium contributions with the two-component exciton model using Kalbach systematics [37], the level density model [38,39], and the γ widths can be almost completely repeated verbatim for the calculations that were performed in this work. The main difference here from the work reported in Ref.…”

Section: Reactionmentioning

confidence: 99%

“…The main difference here from the work reported in Ref. [31] is that new parameters for the matrix element of the internal transition rates of the exciton model have been developed [40], and a modified expression for the shell-dependent total level density parameter has been used. Also, a more modern implementation of Kalbach's complex particle emission model has been used, improving the description of (n, d) up to (n, α) channels.…”

Section: Reactionmentioning

confidence: 99%

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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: Nuclear Model Calculationsmentioning

confidence: 99%

“…[31] for Ni isotopes 044617-4 TABLE III. Measured activation cross sections (mb) for Mo isotopes between 13.5 and 14.8 MeV.…”

Section: A Global Approachmentioning

confidence: 99%

Section: Reactionmentioning

confidence: 99%

Section: Reactionmentioning

confidence: 99%

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

et al. 2005

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“…6: Present calculations of a) (n, n ), (n, 2n) and b) (n, α), (n, nα) cross sections for 59 Co from threshold energies to 25 MeV which are compared with the experimental data taken from the other works [39][40][41] their threshold energies to 25 MeV, compared with the experimental data [39][40][41]. Some of the experimental data shown in Fig.…”

Section: A 59 Comentioning

confidence: 99%

Measurement and model analysis of(n,xα)cross sections for Cr, Fe,59Co, and
Kunieda
¹
,
Haight
²
,
Kawano
³

et al. 2012
Phys. Rev. C
26
0
3
0
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Neutron reactions that produce alpha-particles have been investigated experimentally and analyzed by reaction model calculations for incident neutron energies from threshold to 150 MeV on elemental chromium and iron. The cross sections were measured at the Los Alamos Neutron Science Center by direct observation of alpha-particles. Previous data on isotopes 59 Co and 58,60 Ni were also included in the analysis. The model calculations are made for both statistical decay and pre-equilibrium processes. This study particularly focuses on the pre-equilibrium cluster emission, which is described by the clustering exciton model of Iwamoto and Harada. We calculate the alphaparticle formation factors numerically without any approximations that appeared in the original model. The model parameter ∆R, the nuclear surface area where the pickup reaction may occur, is determined by fitting the calculated alpha-particle energy spectra to experimental data. The calculated alpha-particle production cross sections agree well with the measured data, except for the Cr case. With a simple sensitivity study for the level density parameters, it is reported that relatively small changes in the level density parameters improve reproduction of experimental data significantly. Our realistic model calculations for the pre-equilibrium process shed light on uncertainties in the nuclear level densities in the statistical decay calculation.

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Investigation of Some Stellar Iron Group Fusion Materials for (n, p) Reactions

et al. 2011

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A systematic investigation of reaction cross sections and isomer ratios for neutrons up to 20 MeV on Ni-isotopes and 59Co by measurements with the activation technique and new model studies of the underlying reaction mechanisms

Cited by 57 publications

References 45 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

Measurement and model analysis of(n,xα)cross sections for Cr, Fe,59Co, and
Kunieda
¹
,
Haight
²
,
Kawano
³

et al. 2012
Phys. Rev. C
26
0
3
0
View full text Add to dashboard Cite

Investigation of Some Stellar Iron Group Fusion Materials for (n, p) Reactions

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A systematic investigation of reaction cross sections and isomer ratios for neutrons up to 20 MeV on Ni-isotopes and 59Co by measurements with the activation technique and new model studies of the underlying reaction mechanisms

Cited by 57 publications

References 45 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

Measurement and model analysis of(n,xα)cross sections for Cr, Fe,59Co, andKunieda1, Haight2, Kawano3 et al. 2012Phys. Rev. C26030View full textAdd to dashboardCite

Investigation of Some Stellar Iron Group Fusion Materials for (n, p) Reactions

Contact Info

Product

Resources

About

Measurement and model analysis of(n,xα)cross sections for Cr, Fe,59Co, and
Kunieda
¹
,
Haight
²
,
Kawano
³

et al. 2012
Phys. Rev. C
26
0
3
0
View full text Add to dashboard Cite