Measurement of energy spectra and spatial distributions of neutron beams provided by the ANNRI beamline for capture cross-section measurements at the J-PARC/MLF

K. Kino, M. Furusaka, F. Hiraga, T. Kamiyama, Y. Kiyanagi, K. Furutaka, S. Goko, H. Harada, M. Harada, T. Kai, A. Kimura, Tadahiro Kin, F. Kitatani, M. Koizumi, F. Maekawa, S. Meigo, S. Nakamura, M. Ooi, M. Ohta, M. OshimaY. Toh, M. Igashira, T. Katabuchi, M. Mizumoto

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We measured the energy spectra and spatial distributions of the neutron beam of Accurate Neutron-Nucleus Reaction Measurement Instrument (ANNRI) at the Japan Proton Accelerator Research Complex/Materials and Life Science Experimental Facility (J-PARC/MLF). Our research team designed and built ANNRI to measure nuclear data with high precision. The measurements of the neutron beam were performed on three types of beams provided by ANNRI in the neutron energy range from 1.5 meV to 10 keV. The energy spectra show a typical feature of para-hydrogen moderator, and the absolute intensities almost agree with predictions based on both a simulation calculation of the Japan Spallation Neutron Source (JSNS) and a neutron transmission calculation of the beamline. The available neutron intensities at 21.5 m are 7.5×105, 1.6×104, and 1.1×105 n/cm2/s in the energy ranges 1.525 meV, 0.91.1 eV, and 0.91.1 keV, respectively, under the 17.5 kW JSNS operation. The measured spatial distributions of the beams formed by three different collimators are consistent with those expected from the collimator-system design of the beamline. The beam sizes in FWHM are about 29, 14, and 11 mm for the three different beam collimators. The edges of the spatial distributions are relatively sharp, enabling us to measure the nuclear data successfully.

Original languageEnglish
Pages (from-to)58-66
Number of pages9
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Issue number1
Publication statusPublished - Jan 1 2011
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Instrumentation

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