EPJ Web of Conferences (Jan 2020)

Measurement of the neutron capture cross-section of 237Np using ANNRI at MLF/J-PARC

  • Rovira Gerard,
  • Katabuchi Tatsuya,
  • Tosaka Kenichi,
  • Matsuura Shota,
  • Terada Kazushi,
  • Iwamoto Osamu,
  • Kimura Atsushi,
  • Nakamura Shoji,
  • Iwamoto Nobuyuki

DOI
https://doi.org/10.1051/epjconf/202023901017
Journal volume & issue
Vol. 239
p. 01017

Abstract

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The neutron capture-cross section of 237Np was measured using the Accurate Neutron-Nucleus Reaction Measurement Instrument (ANNRI) with special emphasis in the region of interest for the core design of Accelerator-Driven Systems (ADS), from 0.5 to 500 keV. A neutron time-of-flight method was employed using the NaI(Tl) spectrometer in the ANNRI beamline at the Japanese Proton Accelerator Research Complex (J-PARC) together with the pulse-height weighting technique. The cross-section was determined by normalizing the results to JENDL-4.0 cross-section data at the first resonance of 237Np. In the 0.5 to 500 keV range, the present preliminary results present better agreement with previous experiments of Weston et al [3]. Experimental data from Esch et al [6] is about 15% lower than the present results. In comparision with evaluated data, ENDF/B-VIII.0 offers better agreement from 0.5 to 10 keV than with JENDL-4.0. From 0.5 to 10 keV JENDL-4.0 underestimates the present results by 10-15%. Nontheless, over 10 keV energy JENDL-4.0 shows good agreement up to 500 keV. The present preliminary cross-section has uncertainties of about 5% from 0.5 to 35 keV, a value lower than the uncertainties present in JENDL-4.0 of 6-10%. However, over 35 keV the total uncertainties steadily increase and amount to 10% at 500 keV.