Measurements of the Am neutron capture and total cross sections with ANNRI at J-PARC

Kimura, Atsushi; Nakamura, Shoji; Terada, Kazushi*; Nakao, Taro*; Mizuyama, Kazuhito*; Iwamoto, Nobuyuki; Iwamoto, Osamu; Harada, Hideo; Katabuchi, Tatsuya*; Igashira, Masayuki*; et al.

Journal of Nuclear Science and Technology, 56(6), p.479 - 492, 2019/06

https://doi.org/10.1080/00223131.2019.1598508

Cross section measurements of Gd(n,) induced by thermal and epithermal neutrons

Mastromarco, M.*; Manna, A.*; Aberle, O.*; Andrzejewski, J.*; Harada, Hideo; Kimura, Atsushi; n_TOF Collaboration*; 116 of others*

European Physical Journal A, 55(1), p.9_1 - 9_20, 2019/01

https://doi.org/10.1140/epja/i2019-12692-7

Measurements of neutron total and capture cross sections of Am with ANNRI at J-PARC

Terada, Kazushi*; Kimura, Atsushi; Nakao, Taro*; Nakamura, Shoji; Mizuyama, Kazuhito*; Iwamoto, Nobuyuki; Iwamoto, Osamu; Harada, Hideo; Katabuchi, Tatsuya*; Igashira, Masayuki*; et al.

Journal of Nuclear Science and Technology, 55(10), p.1198 - 1211, 2018/10

https://doi.org/10.1080/00223131.2018.1485519

Systematic effects on cross section data derived from reaction rates in reactor spectra and a re-analysis of Am reactor activation measurements

erovnik, G.*; Schillebeeckx, P.*; Becker, B.*; Fiorito, L.*; Harada, Hideo; Kopecky, S.*; Radulovic, V.*; Sano, Tadafumi*

Nuclear Instruments and Methods in Physics Research A, 877, p.300 - 313, 2018/01

https://doi.org/10.1016/j.nima.2017.09.064

Methodologies to derive cross section data from spectrum integrated reaction rates were studied. The Westcott convention and some of its approximations were considered. The accuracy of the results strongly depends on the assumptions that are made about the neutron energy distribution, which is mostly parameterised as a sum of a thermal and an epi-thermal component. Resonance integrals derived from such data can be strongly biased. When the energy dependence of the cross section is known and information about the neutron energy distribution is available, a method to correct for a bias on the cross section at thermal energy is proposed. Reactor activation measurements to determine the thermal Am(n, ) cross section reported in the literature were reviewed, where the results were corrected to account for possible biases. These data combined with results of time-of-flight measurements give a capture cross section 720 (14) b for Am(n, ) at thermal energy.

Technical developments for accurate determination of amount of samples used for TOF measurements

Terada, Kazushi; Nakao, Taro; Nakamura, Shoji; Kimura, Atsushi; Iwamoto, Osamu; Harada, Hideo; Takamiya, Koichi*; Hori, Junichi*

EPJ Web of Conferences (Internet), 146, p.03019_1 - 03019_4, 2017/09

https://doi.org/10.1051/epjconf/201714603019

The research project entitled "Research and development for Accuracy Improvement of neutron nuclear data on Minor ACtinides (AIMAC)" has been started to improve the reliability of the neutron cross section date of MAs. In order to obtain accurate cross section data, it is indispensable to determine the amount of MA sample accurately and non-destructively. However, the uncertainty concerning the amount of sample is not assured in some cases. Therefore, as a part of the AIMAC project, this study is aimed to development the technique for accurate determination of the amount of samples by two different methods: -ray spectroscopic method and calorimetric method. This contribution presents the developed techniques together with results obtained by two independent techniques.

Developments of a new data acquisition system at ANNRI

Nakao, Taro; Terada, Kazushi; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Osamu; Harada, Hideo; Katabuchi, Tatsuya*; Igashira, Masayuki*; Hori, Junichi*

EPJ Web of Conferences (Internet), 146, p.03021_1 - 03021_4, 2017/09

https://doi.org/10.1051/epjconf/201714603021

A new data acquisition system (DAQ system) in J-PARC Materials and Life Science Experimental Facility (MLF) ANNRI was developed. Increasing beam power of MLF in recent years allows beam line users to obtain high quantity experimental data yields. Compared to 2008, more than 20 times beam current is achieved in 2015. For the purpose to correspond strong beam power of MLF, a new DAQ system for the array of the Ge detectors in ANNRI is developed. The DAQ system is also going to be used for processing signals from a Li glass detector, which is under development at ANNRI for measurement of total neutron cross sections. Commissioning experiment of a new DAQ system at ANNRI was performed by using 0.1mmt Au sample with 500kW J-PARC proton beam power. An applicability of time-of-flight method for both neutron capture and total cross-sections measurements was checked. ADC and TDC nonlinearity, energy resolution, multi-channel coincidence and dead time performance for the array of the Ge detectors were also evaluated. The dead time value for Ge detectors was successfully decreased to 1/4 from the previous DAQ system with minor deterioration on energy resolution. The author would like to thank the accelerator and technical staff at J-PARC for operation of the accelerator and the neutron production target and for the other experimental supports. Present study includes the result of "Research and Development for accuracy improvement of neutron nuclear data on minor actinides" entrusted to the Japan Atomic Energy Agency by the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT).

Improving nuclear data accuracy of Am and Np capture cross sections

erovnik, G.*; Schillebeeckx, P.*; Cano-Ott, D.*; Jandel, M.*; Hori, Junichi*; Kimura, Atsushi; Rossbach, M.*; Letourneau, A.*; Noguere, G.*; Leconte, P.*; et al.

EPJ Web of Conferences (Internet), 146, p.11035_1 - 11035_4, 2017/09

https://doi.org/10.1051/epjconf/201714611035

High precision analysis of isotopic composition for samples used for nuclear cross-section measurements

Shibahara, Yuji*; Hori, Junichi*; Takamiya, Koichi*; Fujii, Toshiyuki*; Fukutani, Satoshi*; Sano, Tadafumi*; Harada, Hideo

EPJ Web of Conferences (Internet), 146, p.03028_1 - 03028_4, 2017/09

https://doi.org/10.1051/epjconf/201714603028

Characterization of the n_TOF EAR-2 neutron beam

Chen, Y. H.*; Tassan-Got, L.*; Harada, Hideo; Kimura, Atsushi; n_TOF Collaboration*; 130 of others*

EPJ Web of Conferences (Internet), 146, p.03020_1 - 03020_4, 2017/09

https://doi.org/10.1051/epjconf/201714603020

The experimental area 2 (EAR-2) at CERNs neutron time-of-flight facility (n_TOF), which is operational since 2014, is designed and built as a short-distance complement to the experimental area 1 (EAR-1). The Parallel Plate Avalanche Counter (PPAC) monitor experiment was performed to characterize the beam profile and the shape of the neutron flux at EAR-2. The prompt -flash which is used for calibrating the time-of-flight at EAR-1 is not seen by PPAC at EAR-2, shedding light on the physical origin of this -flash.

Dissemination of data measured at the CERN n_TOF facility

Dupont, E.*; Otsuka, Naohiko*; Harada, Hideo; Kimura, Atsushi; n_TOF Collaboration*; 224 of others*

EPJ Web of Conferences (Internet), 146, p.07002_1 - 07002_4, 2017/09

https://doi.org/10.1051/epjconf/201714607002

The n_TOF neutron time-of-flight facility at CERN is used for high quality nuclear data measurements from thermal energy up to hundreds of MeV. In line with the CERN open data policy, the n_TOF Collaboration takes actions to preserve its unique data, facilitate access to them in standardised format, and allow their re-use by a wide community in the fields of nuclear physics, nuclear astrophysics and various nuclear technologies. The present contribution briefly describes the n_TOF outcomes, as well as the status of dissemination and preservation of n_TOF final data in the international EXFOR library.