Evaluation of neutron total and capture cross sections on99Tc in the unresolved resonance region

Nobuyuki Iwamoto,Tatsuya Katabuchi

doi:10.1051/epjconf/201714602049

Nobuyuki Iwamoto, Tatsuya Katabuchi

Open Access

https://doi.org/10.1051/epjconf/201714602049

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Abstract

Long-lived fission product Technetium-99 is one of the most important radioisotopes for nuclear transmutation. The reliable nuclear data are indispensable for a wide energy range up to a few MeV, in order to develop environmental load reducing technology. The statistical analyses of resolved resonances were performed by using the truncated Porter-Thomas distribution, coupled-channels optical model, nuclear level density model and Bayes' theorem on conditional probability. The total and capture cross sections were calculated by a nuclear reaction model code CCONE. The resulting cross sections have statistical consistency between the resolved and unresolved resonance regions. The evaluated capture data reproduce those recently measured at ANNRI of J-PARC/MLF above resolved resonance region up to 800 keV.

Highlights

Radioactive Technetium-99 has a characteristic of long half-life (2.11 × 105 yr)
The experiments by time-of-flight and lead slowingdown time techniques have been performed for capture cross section up to the unresolved resonance region [2,3,4,5,6]
The experiment by the time-of-flight method was recently made with a NaI(Tl) spectrometer of ANNRI installed at the Materials and Life Science Experimental Facility (MLF) of J-PARC [7]

Summary

Introduction

Radioactive Technetium-99 has a characteristic of long half-life (2.11 × 105 yr). This long-lived fission product is generated by e.g. 235U fission in nuclear power plants and the cumulative fission yield exceeds 6% [1]. The experiments by time-of-flight and lead slowingdown time techniques have been performed for capture cross section up to the unresolved resonance region [2,3,4,5,6]. Their measured data show a dispersion of ∼20% in that region. The capture cross section was obtained over a wide region from the thermal energy up to several hundred keV energies

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Results

Conclusion