Excitation functions of (n, α) reaction cross-sections for some important isotopes from threshold to 20 MeV

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Abstract

The (n, α) reaction cross-sections from threshold to ∼20 MeV on some important nuclides 42Ca, 50,53Cr, 56,57Fe, 58,62Ni, and 63,65Cu involved in the reactor shielding design have been calculated using the Hauser–Feshbach statistical model with preequilibrium effects by involving PCROSS option in Empire 2.19. The transmission coefficients for neutrons in the entrance channel are calculated using the optical model potential of Koning. In the exit channel optical model potential of Avrigeanu has been used. The experimental values have been chosen carefully for all the isotopes, from EXFOR data base. The calculations are compared with existing experimental data as well as with evaluated data files (ENDF/B-VI.0 and JENDL-3.3). A good agreement between the calculated and experimental data validates the nuclear model approaches with increased predictive power to supplement and extend the nuclear database that is required for several applications.

Research highlights

► Excitation functions for 53,42Ca, 57Fe isotopes having no entries in the EXFOR. ► Emphasis on Gilbert Cameron formalism for level density calculations. ► Suitability of Avrigeanu’s alpha potential for the (n, α) reaction cross-sections. ► Supports the ENDF/B-VI data library.

Introduction

The (n, α) reactions cross-section data is of paramount importance from the viewpoint of fusion and advanced fission reactor technology especially for calculations on nuclear transmutation rates, nuclear heating and radiation damage to the materials used in the construction of the core and inner walls of the reactor. Most of the (n, α) reaction cross-section data are available at ∼14 MeV. New nuclear energy system requires significant amount of new nuclear data in extended energy region and improvement of the presently available nuclear data. The present situation of (n, α) reaction cross-section data for the energy region from threshold to ∼20 MeV is still scanty and discrepant because preparing a mono-energetic neutron source for activation experiment in this energy region (except ∼14 MeV) presents some difficulties. Moreover, limitations of the activation technique to the stable products, unsuitable half lives and uncertain decay schemes account for the lack of the data. This lack of experimental data has to be compensated by the development of reliable calculation methods. EMPIRE-II code Herman et al. (2007) has opened up options for calculating cross-sections for various reaction channels. In this paper, we present model based calculations for (n, α) reaction cross-sections on isotopes which have been identified in IAEA nuclear data committee report INDC(SEC) – 95/URSF as priority isotopes for new nuclear energy generating systems.

Section snippets

Calculations

The cross-sections for (n, α) reactions on 42Ca, 50,53Cr, 56,57Fe, 58,62Ni, and 63,65Cu from threshold to ∼20 MeV have been calculated using the computer code EMPIRE-II which is a recent and versatile code for nuclear cross-section calculations. These cross-sections are theoretically calculated using full featured Hauser–Feshbach statistical model with preequilibrium and direct contributions. The nuclear structure input to the calculations like nuclear masses, discrete energy levels and level

Results and discussion

The results of the calculations are plotted in Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9. The bell like shape of the excitations curves is typical characteristics of compound nucleus which rises abruptly above the reaction threshold and descends due to the competitive reactions and the increase of the preequilibrium contribution with neutron energy. For 42Ca, 53Cr, and 57Fe isotopes there are no entries in the EXFOR data library. The limitations of the activation

Conclusions

The present study done on the (n, α) reaction cross-sections for the isotopes of interest to nuclear fission and fusion reactors is thus significant in the context of the existing discrepant nuclear database available for these isotopes. The model based calculations of (n, α) reaction cross-sections of the nuclides performed in the present study showed that the Gilbert–Cameron formalism for level density calculations is appropriate in the energy range from threshold to 20 MeV for the studied

References (35)

  • J. Kantele et al.

    Some activation cross-sections for 14.7 MeV neutrons

    Nucl. Phys.

    (1962)
  • A.J. Koning et al.

    Local and global nucleonoptical models from 1 KeV to 200 MeV

    Nucl. Phys. A

    (2003)
  • O.I. Artemèv

    Cross sections for (n, p) and (n, α) reactions on chromium, iron, copper and molybdenum nuclei at a neutron energy of 14.8 MeV

    Atomnaya Energiya

    (1980)
  • V. Avrigeanu et al.

    Global optical potentials for emitted alpha particles

    Phys. Rev. C

    (1994)
  • Belgya, T., et al., 2006. Handbook for calculation of nuclear reaction data, RIPL-2 IAEA-TECDOC-1506 IAEA, Vienna....
  • E.T. Bramlitt et al.

    Rare nuclear reactions induced by 14.7 MeV neutrons

    Phys. Rev.

    (1963)
  • Clator, I.G., 1969. Neutron induced reactions between 14.4 and 16.7MeV. Thesis or dissertation Name....
  • F. Cserpák et al.

    Excitation functions and isomeric cross section ratios of the 63Cu(n, α)60Com, g, 65Cu(n, α)62Com, g and 60Ni(n, p)60Com, g processes from 6 to 15 MeV

    Phys. Rev., Part C Nucl. Phys.

    (1994)
  • C. Derndorfer et al.

    Investigation of the 50Cr(n, α)47Ti reaction at En = 14.1 MeV

    Zeitschrift fuer Physik, A

    (1981)
  • Ercan, A. et al., 1991. 14.6MeV neutron induced reaction cross-sections measurements. In: Conf. Nucl. Data Sci....
  • Evaluated Nuclear Data File. ENDF BNL,...
  • A. Fessler et al.

    Excitation functions of 50Cu(n, np+pn+d)49V, 58Ni(n, a)55Fe, 58Ni(n, ap+pa)54Mn and 62Ni(n, a)59Fe reactions

    Radiochim. Acta

    (1999)
  • Filatenkov, A.A., et al., 1999. Systematic measurement of activation cross sections At neutron energies from 13.4 to...
  • Fukuda, K., et al., 1978. Activation cross-sections on Fe, Co, Ni, Zr and Mo for 14.6MeV neutrons, vol. 44. Japanese...
  • A. Gilbert et al.

    A composite nuclear-level density formula with shell corrections

    Can. J. Phys.

    (1965)
  • L.R. Greenwood

    Recent research in neutron dosimetry and damage analysis for materials irradiations

    Am. Soc. Test. Mater. Rep.

    (1987)
  • A.K.M. Harun-Ar-Rashid

    Measurement of cross-sections for the reactions 65Cu(n, alpha)62gCo, 65Cu(n, p)65Ni, 65Cu(n, 2n)64Cu, 58Ni(n, 2n)57Ni and 58Ni(n, p)58m+g Co at 14.8 MeV neutron energy

    Indian J. Phys.

    (2006)
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