JAEA-Conf 2011-002 - 日本原子力研究開発機構

JAEA-Conf 2011-002
6. Measurements of Neutron Capture Cross Sections at
J-PARC/MLF/ANNRI (2)
Measurements of Neutron Capture Cross Sections of
Long-Lived Fission Products using a high intensity pulsed neutron source
J. HORI1, T. FUJII1, S. FUKUTANI1, M. FURUSAKA4, K. FURUTAKA2, S. GOKO2,a, H. HARADA2, F. HIRAGA4, M. IGASHIRA3, T. KAMIYAMA4, T. KATABUCHI3, A. KIMURA2, T. KIN 2, K. KINO4,b, F. KITATANI2, Y. KIYANAGI4, M. KOIZUMI2, M. MIZUMOTO3, S. NAKAMURA2, M. OHTA2,c, M. OSHIMA2, K. TAKAMIYA1, and Y. TOH2 1Research Reactor Institute, Kyoto University
2Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency
3Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology
4Graduate School of Engineering, Hokkaido University
Present address : a Hokkaido University, b High Energy Accelerator Research Organization, c Osaka University
e-mail: hori@rri.kyoto-u.ac.jp
The neutron capture cross sections of 93Zr, 99Tc and 107Pd have been measured relative to
the 10B(n,) standard cross section by the neutron time-of-flight (TOF) method. Neutron
capture rays were measured with a 4 Ge spectrometer as a part of the Accurate
Neutron-Nucleus Reaction measurement Instrument (ANNRI) installed at the neutron Beam
Line No.4 (BL04) of the Material and Life science experimental Facility (MLF) in the Japan
Proton Accelerator Research Complex (J-PARC). This paper presents the preliminary results.
1. Introduction
The neutron capture cross sections of long-lived fission products (LLFPs) are of great
importance for the research of the nuclear transmutation of radioactive waste. Seven nuclei of
79Se, 93Zr, 99Tc, 107Pd, 126Sn, 129I and 135Cs were selected as the most important LLFPs [1]. At
first, the current status of experimental data on neutron capture cross sections of those nuclei
is summarized briefly.
There are no experimental data for 79Se. As for the status of 126Sn and 135Cs, there are
only available experimental data with the activation method. It is noted that the only
experimental result of 126Sn was recently reported at the thermal energy [2]. For 93Zr and
107Pd, the experimental data obtained by the neutron time-of-flight (TOF) method at the Oak
Ridge Electron Linear Accelerator (ORELA) are only available in the resonance region [3,4].
Since a pair of C6D6 detectors was used as a capture -ray detector in the works, the effects
due to the isotope impurities contained in a sample were subtracted by using the other
experimental data on those isotopes. Therefore, the uncertainty associated with subtraction