Gubler, P.; Bratkovskaya, E.*; Song, T.*
EPJ Web of Conferences, 274, p.07015_1 - 07015_6, 2022/12
Kajimoto, Ryoichi; Nakamura, Mitsutaka; Kamazawa, Kazuya*; Inamura, Yasuhiro; Iida, Kazuki*; Ikeuchi, Kazuhiko*; Ishikado, Motoyuki*
EPJ Web of Conferences, 272, p.02007_1 - 02007_8, 2022/11
Gubler, P.; Bratkovskaya, E.*
EPJ Web of Conferences, 271, p.09004_1 - 09004_4, 2022/11
Yamamoto, Takeshi; Fujita, Manami; Gogami, Toshiyuki*; Harada, Takeshi*; Hayakawa, Shuhei*; Hosomi, Kenji; Ichikawa, Yudai; Ishikawa, Yuji*; Kamata, K.*; Kanauchi, H.*; et al.
EPJ Web of Conferences, 271, p.03001_1 - 03001_5, 2022/11
Nakajima, Kenji; Kikuchi, Tatsuya*; Kawamura, Seiko; Kambara, Wataru*
EPJ Web of Conferences, 272, p.02012_1 - 02012_8, 2022/11
We will present some of attempts on AMATEAS, a cold-neutron chopper spectrometer at a pulsed source, to increase time-windows at a single-measurement condition. One of ways is that, by allowing interveined trajectories on the time-of-flight diagram, the usable width selectable for is can be increased. Based on our experiences, the conditions of pulse repetition rate multiplication based polychromatic measurements on chopper spectrometers at pulsed sources will be discussed. Optimization of wide-band polychromatic measurements and a generalized formulated condition will be proposed. Application of our idea to existing spectrometers and to the criteria design of an optimized chopper spectrometer will be also discussed with suggesting further possibility to improve efficiency by modifying the pulse shaping chopper.
Fukaya, Yuji; Goto, Minoru; Nakagawa, Shigeaki; Nakajima, Kunihiro*; Takahashi, Kazuki*; Sakon, Atsushi*; Sano, Tadafumi*; Hashimoto, Kengo*
EPJ Web of Conferences, 247, p.09017_1 - 09017_8, 2021/02
The Japan Atomic Energy Agency (JAEA) started the Research and Development (R&D) to improve nuclear prediction techniques for High Temperature Gas-cooled Reactors (HTGRs). The objectives are to introduce a generalized bias factor method to avoid full mock-up experiment for the first commercial HTGR and to introduce reactor noise analysis to High Temperature Engineering Test Reactor (HTTR) experiment to observe subcriticality. To achieve the objectives, the reactor core of graphite-moderation system named B7/4"G2/8"p8EUNU+3/8"p38EU(1) was newly composed in the B-rack of Kyoto University Critical Assembly (KUCA). The core is composed of the fuel assembly, driver fuel assembly, graphite reflector, and polyethylene reflector. The fuel assembly is composed of enriched uranium plate, natural uranium plate and graphite plates to realize the average fuel enrichment of HTTR and it's spectrum. However, driver fuel assembly is necessary to achieve the criticality with the small-sized core. The core plays a role of the reference core of the bias factor method, and the reactor noise was measured to develop the noise analysis scheme. In this study, the overview of the criticality experiments is reported. The reactor configuration with graphite moderation system is rare case in the KUCA experiments, and this experiment is expected to contribute not only for an HTGR development but also for other types of a reactor in the graphite moderation system such as a molten salt reactor development.
Sakon, Atsushi*; Nakajima, Kunihiro*; Takahashi, Kazuki*; Hohara, Shinya*; Sano, Tadafumi*; Fukaya, Yuji; Hashimoto, Kengo*
EPJ Web of Conferences, 247, p.09009_1 - 09009_8, 2021/02
In graphite-reflected thermal reactors, even a detector placed far from fuel region may detect a certain degree of the correlation amplitude. This is because mean free path of neutrons in graphite is longer than that in water or polyethylene. The objective of this study is experimentally to confirm a high flexibility of neutron detector placement in graphite reflector for reactor noise analysis. The present reactor noise analysis was carried out in a graphite-moderated and -reflected thermal core in Kyoto University Critical Assembly (KUCA). BF proportional neutron counters (1" dia.) were placed in graphite reflector region, where the counters were separated by about 35cm and 30cm -thick graphite from the core, respectively. At a critical state and subcritical states, time-sequence signal data from these counters were acquired and analyzed by a fast Fourier transform (FFT) analyzer, to obtain power spectral density in frequency domain. The auto-power spectral density obtained from the counters far from the core contained a significant degree of correlated component. A least-squares fit of a familiar formula to the auto-power spectral density data was made to determine the prompt-neutron decay constant. The decay constant was 63.314.5 [1/s] in critical state. The decay constant determined from the cross-power spectral density and coherence function data between the two counters also had a consistent value. It is confirmed that reactor noise analysis is possible using a detector placed at about 35cm far from the core, as we expected.
Watanabe, Yukinobu*; Sadamatsu, Hiroki*; Araki, Shohei*; Nakano, Keita*; Kawase, Shoichiro*; Kin, Tadahiro*; Iwamoto, Yosuke; Satoh, Daiki; Hagiwara, Masayuki*; Yashima, Hiroshi*; et al.
EPJ Web of Conferences, 239, p.20012_1 - 20012_4, 2020/09
Accelerator-based neutron sources induced by deuteron beams are attractive for study of nuclear transmutation of radioactive waste as well as radiation damage for fusion reactor materials. In the present work, we have carried out a Double Differential cross section (DDX) measurement for Li at 200 MeV in the Research Center for Nuclear Physics (RCNP), Osaka University. A deuteron beam accelerated to 200 MeV was transported to the neutron experimental hall and focused on a thin Li target. Emitted neutrons from the target were detected by two different-size EJ301 liquid organic scintillators located at two distances of 7 m and 20 m, respectively. The neutron DDXs were measured at six angles from 0 to 25). The neutron detection efficiencies of the detectors were calculated by SCINFUL-QMD code. We will present the results of the present DDX measurement and compare them with theoretical model calculations with DEURACS and PHITS.
Nakayama, Shinsuke; Iwamoto, Osamu; Watanabe, Yukinobu*
EPJ Web of Conferences, 239, p.03014_1 - 03014_4, 2020/09
Intensive neutron sources using deuteron accelerators have been proposed for various applications such as irradiation test for fusion reactor materials and production of radioisotopes for medical use. In addition, transmutation system using deuteron-induced spallation reactions has been recently proposed for LLFPs. Accurate and comprehensive deuteron nuclear data are indispensable in the design study of such facilities. Under the above situations, we have been developing a code system dedicated for deuteron-induced reactions, which is called DEURACS. In the present work, calculations using DEURACS are compared with available experimental data up to 200 MeV such as DDXs for emission of neutron or light charged particles. We also analyze isotopic production cross sections of residual nuclei. Validation of the present modelling in DEURACS is discussed through comparison with the experimental data.
Iwamoto, Osamu; Iwamoto, Nobuyuki; Shibata, Keiichi; Ichihara, Akira; Kunieda, Satoshi; Minato, Futoshi; Nakayama, Shinsuke
EPJ Web of Conferences, 239, p.09002_1 - 09002_6, 2020/09
Iwamoto, Nobuyuki; Nakamura, Shoji; Kimura, Atsushi; Katabuchi, Tatsuya*; Rovira, G.*; Hara, Kaoru*; Iwamoto, Osamu
EPJ Web of Conferences, 239, p.17016_1 - 17016_4, 2020/09
Iwamoto, Yosuke; Meigo, Shinichiro
EPJ Web of Conferences, 239, p.20011_1 - 20011_4, 2020/09
PHITS including the NRT model can calculate displacement cross sections of materials for various particle irradiations in wide energy range. Recently, Nordlund et al. provided the athermal recombination corrected (arc) displacement per atom (dpa) function providing more physically realistic descriptions of primary defect creation in materials. Therefore, the arc-dpa will be used for efficient predictions of the usable lifetime of materials in various accelerator facilities. In this work, the arc-dpa function related with the defect production efficiency was implemented in the radiation damage model in PHITS. As a result, for the displacement cross sections of Cu and W under proton irradiations with energies above 100 MeV, the arc-dpa cross sections are smaller than the NRT-dpa cross sections by a factor of about 3. In this presentation, we will present the arc-dpa cross sections for proton, deuteron and heavy-ion irradiations in the energy region between 100 MeV/u and 3 GeV/u.
Hashimoto, Shintaro; Sato, Tatsuhiko
EPJ Web of Conferences, 239, p.03015_1 - 03015_4, 2020/09
Particle transport simulation codes based on the Monte Carlo technique have been successfully applied to shielding calculations in accelerator facilities. Estimation of not only statistical uncertainties, which depend on the number of trials, but also systemic uncertainties, which are caused by uncertainty of total cross section models, is required to confirm the reliability of the simulation results. We evaluated unclear quantities of internal parameters included in the total cross section model by the KALMAN code, which is based on the least squares technique, comparing with experimental data of the total cross section. The uncertainties in the total cross sections obtained by the new model are comparable to the experimental errors. In the present study, the systematic uncertainty included in the simulation results can be estimated by performing the transport calculations with variation of the internal parameters within their unclear quantities.
Dupont, E.*; Bossant, M.*; Capote, R.*; Carlson, A. D.*; Danon, Y.*; Fleming, M.*; Ge, Z.*; Harada, Hideo; Iwamoto, Osamu; Iwamoto, Nobuyuki; et al.
EPJ Web of Conferences, 239, p.15005_1 - 15005_4, 2020/09
Katabuchi, Tatsuya*; Iwamoto, Osamu; Hori, Junichi*; Kimura, Atsushi; Iwamoto, Nobuyuki; Nakamura, Shoji; Shibahara, Yuji*; Terada, Kazushi*; Rovira, G.*; Matsuura, Shota*
EPJ Web of Conferences, 239, p.01044_1 - 01044_4, 2020/09
Fleming, M.*; Chadwick, M.*; Brown, D.*; Capote, R.*; Ge, Z.*; Herman, M.*; Ignatyuk, A.*; Ivanova, T.*; Iwamoto, Osamu; Koning, A.*; et al.
EPJ Web of Conferences, 239, p.15003_1 - 15003_5, 2020/09
Fleming, M.*; Bernard, D.*; Brown, D.*; Chadwick, M. B.*; De Saint Jean, C.*; Dupont, E.*; Ge, Z.*; Harada, Hideo; Hawari, A.*; Herman, M.*; et al.
EPJ Web of Conferences, 239, p.15002_1 - 15002_4, 2020/09
Rodriguez, D.; Abbas, K.*; Crochemore, J.-M.*; Koizumi, Mitsuo; Nonneman, S.*; Pedersen, B.*; Rossi, F.; Seya, Michio*; Takahashi, Tone
EPJ Web of Conferences, 239, p.17005_1 - 17005_5, 2020/09
Iwamoto, Hiroki; Meigo, Shinichiro; Matsuda, Hiroki
EPJ Web of Conferences, 239, p.06001_1 - 06001_6, 2020/09
no abstracts in English
Matsuda, Hiroki; Meigo, Shinichiro; Iwamoto, Hiroki; Maekawa, Fujio
EPJ Web of Conferences, 239, p.06004_1 - 06004_4, 2020/09
For the Accelerator-Driven nuclear transmutation System (ADS), nuclide production yield estimation in the lead-bismuth target is important to manage the target. However, experimental data of nuclide production yield by spallation and high-energy fission reactions are scarce. In order to obtain the experimental data, we experimented in J-PARC using Pb and Bi samples. The samples were irradiated with protons at various kinematic energy points between 0.4 and 3.0 GeV. After the irradiation, the nuclide production cross section over Be to Re was obtained by spectroscopic measurement of decay gamma-rays from the samples with HPGe detectors. The present experimental results were compared with the evaluated data (JENDL-HE/2007) and the calculation with the PHITS code and the INCL++ code. The present experiment data showed consistency with other experimental data with better accuracy than other ones. In reactions to produce light nuclides, JENDL and calculation with the PHITS and INCL++ for Be production agreed with the data.Na production, however, underestimated about 1/10 times. For middle to heavy nuclide productions cases, both calculations agreed with the experiment by a factor of two. JENDL showed lower energy having a maximum value of excitation function maximal value than the experimental data.