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Dupont, E.*; 大塚 直彦*; 原田 秀郎; 木村 敦; n_TOF Collaboration*; 他224名*
EPJ Web of Conferences, 146, p.07002_1 - 07002_4, 2017/09
被引用回数：4 パーセンタイル：90.81(Nuclear Science & Technology)CERNのn_TOF中性子飛行時間測定施設は、高品質の核データを熱エネルギーから数百MeVまでのエネルギー範囲で測定するために利用されている。CERNのデータ公開ポリシーに従い、核物理、宇宙核物理、原子力技術分野の広いコミュニティーに対し取得データを提供するため、n_TOF国際共同研究により取得されたデータは、標準的なフォーマットでの公開を目指している。本論文では、n_TOF国際共同研究によりこれまでに得られた様々なデータ及び関連情報を集約するとともに、国際的標準フォーマットであるEXFOR形式での整備状況について報告する。
Pu(n, 
) cross section at n_TOF-EAR1 for MOX fuels; Preliminary results in the RRRLerendegui-Marco, J.*; Guerrero, C.*; 原田 秀郎; 木村 敦; n_TOF Collaboration*; 他115名*
EPJ Web of Conferences, 146, p.11045_1 - 11045_4, 2017/09
被引用回数：1 パーセンタイル：61.21(Nuclear Science & Technology)軽水炉及び高速炉でのMOX燃料利用にあたり、高精度の中性子捕獲断面積及び核分裂断面積が必要とされており、NEAの専門家会合WPEC-26の報告書によれば、特にPuの中性子捕獲断面積について、500eVから500keVのエネルギー領域に対して7
12%の精度が必要とされている。しかしながら、keV領域の測定値としては、不確かさが約35%と大きな1970年代のデータしかこの40年間存在しなかった。本論文では、n_TOF施設の第1実験室において測定実験を実施し、取得したデータを解析して得られた個々の中性子共鳴パラメータ及びその平均値について暫定結果を示す。
Gunsing, F.*; Aberle, O.*; 原田 秀郎; 木村 敦; n_TOF Collaboration*; 他147名*
EPJ Web of Conferences, 146, p.11002_1 - 11002_6, 2017/09
被引用回数：4 パーセンタイル：90.81(Nuclear Science & Technology)CERNのn_TOF中性子飛行時間測定施設は、2001年の事業開始以来、数多くの実験データ取得に利用されてきた。長期に渡り利用された中性子飛行距離185mの第1実験室に加え、2014年からは中性子飛行距離20mの第2実験室が利用可能となり、施設の測定能力が大幅に向上した。n_TOF施設における核データ測定研究活動について総括的に報告する。
Pu(n,f) cross-section at the CERN n_TOF facility; First results from experimental area II (EAR-2)Stamatopoulos, A.*; Tsinganis, A.*; Colonna, N.*; 原田 秀郎; 木村 敦; n_TOF Collaboration*; 他126名*
EPJ Web of Conferences, 146, p.04030_1 - 04030_4, 2017/09
被引用回数：6 パーセンタイル：95.25(Nuclear Science & Technology)The accurate knowledge of the neutron-induced fission cross-sections of actinides and other isotopes involved in the nuclear fuel cycle is essential for the design of advanced nuclear systems, such as Generation-IV nuclear reactors. Such experimental data can also provide the necessary feedback for the adjustment of nuclear model parameters used in the evaluation process, resulting in the further development of nuclear fission models. In the present work, the Pu(n,f) cross-section was measured at CERN n_TOF facility relative to the well-known 
U(n,f) cross section, over a wide range of neutron energies, from meV to almost MeV, using the time-of-flight technique and a set-up based on Micromegas detectors. This measurement was the first experiment to be performed at n_TOF new experimental area (EAR-2), which offers a significantly higher neutron flux compared to the already existing experimental area (EAR-1).Preliminary results as well as the experimental procedure, including a description of the facility and the data handling and analysis, are presented.
Lerendegui-Marco, J.*; Cort
s-Giraldo, M. A.*; Guerrero, C.*; 原田 秀郎; 木村 敦; n_TOF Collaboration*; 他114名*
EPJ Web of Conferences, 146, p.03030_1 - 03030_4, 2017/09
被引用回数：0 パーセンタイル：0.08(Nuclear Science & Technology)Monte Carlo (MC) simulations are an essential tool to determine fundamental features of a neutron beam, such as the neutron flux or the ray background, that sometimes can not be measured or at least not in every position or energy range. Until recently, the most widely used MC codes in this field had been MCNPX and FLUKA. However, the Geant4 toolkit has also become a competitive code for the transport of neutrons after the development of the native Geant4 format for neutron data libraries, G4NDL. In this context, we present the Geant4 simulations of the neutron spallation target of the n TOF facility at CERN, done with version 10.1.1 of the toolkit. The first goal was the validation of the intra-nuclear cascade models implemented in the code using, as benchmark, the characteristics of the neutron beam measured at the first experimental area (EAR1), especially the neutron flux and energy distribution, and the time distribution of neutrons of equal kinetic energy, the so-called Resolution Function. The second goal was the development of a Monte Carlo tool aimed to provide useful calculations for both the analysis and planning of the upcoming measurements at the new experimental area (EAR2) of the facility.
Be(n,
) and Be(n,p) cross-section measurement for the cosmological lithium problem at the n_TOF facility at CERNBarbagallo, M.*; Colonna, N.*; Aberle, O.*; 原田 秀郎; 木村 敦; n_TOF Collaboration*; 他125名*
EPJ Web of Conferences, 146, p.01012_1 - 01012_4, 2017/09
被引用回数：1 パーセンタイル：61.21(Nuclear Science & Technology)The Cosmological Lithium Problem refers to the large discrepancy between the abundance of primordial Li predicted by the standard theory of Big Bang Nucleosynthesis and the value inferred from the so-called "Spite plateau" in halo stars. A possible explanation for this longstanding puzzle in Nuclear Astrophysics is related to the incorrect estimation of the destruction rate of Be, which is responsible for the production of 95% of primordial Lithium. While charged-particle induced reactions have mostly been ruled out, data on the Be(n,) and Be(n,p) reactions are scarce or completely missing, so that a large uncertainty still affects the abundance of Li predicted by the standard theory of Big Bang Nucleosynthesis. Both reactions have been measured at the n_TOF facility at CERN, providing for the first time data in a wide neutron energy range.
Chiaveri, E.*; Aberle, O.*; Andrzejewski, J.*; 原田 秀郎; 木村 敦; n_TOF Collaboration*; 他111名*
EPJ Web of Conferences, 146, p.03001_1 - 03001_4, 2017/09
被引用回数：1 パーセンタイル：61.21(Nuclear Science & Technology)The CERN n_TOF neutron beam facility is characterized by a very high instantaneous neutron flux, excellent TOF resolution at the 185m long flight path (EAR-1), low intrinsic background and coverage of a wide range of neutron energies, from thermal to a few GeV. The overall efficiency of the experimental program and the range of possible measurements has been expanded with the construction of a second experimental area (EAR-2), located 20m on the vertical of the n_TOF spallation target. This upgrade, which benefits from a neutron flux 30 times higher than in EAR-1, provides a substantial extension in measurement capabilities, opening the possibility to collect data on neutron cross-section of isotopes with short half-lives or available in very small amounts. We will discuss the innovative features of the EAR-2 neutron beam that make possible to perform very challenging measurements on short-lived radioisotopes or sub-mg samples, out of reach up to now at other neutron facilities around the world. Finally, the future perspectives of the facility will be presented.
Pm and 
Tm for astrophysicsGuerrero, C.*; Lerendegui-Marco, J.*; Domingo-Pardo, C.*; 原田 秀郎; 木村 敦; n_TOF Collaboration*; 他113名*
EPJ Web of Conferences, 146, p.01007_1 - 01007_4, 2017/09
被引用回数：1 パーセンタイル：61.21(Nuclear Science & Technology)The neutron capture cross section of several key unstable isotopes acting as branching points in the s-process are crucial for stellar nucleosynthesis studies, but they are very challenging to measure due to the difficult production of sufficient sample material, the high activity of the resulting samples, and the actual (n,) measurement, for which high neutron fluxes and effective background rejection capabilities are required. Capture cross section of Pm and Tm have been measured for time-of-flight measurements at the CERN n_TOF facility using the 19 and 185m beam lines. Activation experiments on the same Pm and Tm targets with a high-intensity 30 keV quasi-Maxwellian flux of neutrons will be performed using the SARAF accelerator and the Liquid-Lithium Target (LiLiT) in order to extract the corresponding Maxwellian Average Cross Section (MACS). The status of these experiments and preliminary results will be presented and discussed as well.
Be(n, ) reaction at n_TOFCosentino, L.*; Musumarra, A.*; Barbagallo, M.*; Pappalardo, A.*; 原田 秀郎; 木村 敦; n_TOF Collaboration*; 他126名*
Nuclear Instruments and Methods in Physics Research A, 830, p.197 - 205, 2016/09
被引用回数：19 パーセンタイル：86.84(Instruments & Instrumentation)The newly built second experimental area EAR2 of the n_TOF spallation neutron source at CERN allows to perform (n, charged particles) experiments on short-lived highly radioactive targets. This paper describes a detection apparatus and the experimental procedure for the determination of the cross-section of the Be(n, ) reaction, which represents one of the focal points toward the solution of the cosmological Lithium abundance problem, and whose only measurement, at thermal energy, dates back to 1963. This newly developed setup could likely be useful also to study other challenging reactions requiring the detectors to be installed directly in the neutron beam.
Wei
, C.*; Chiaveri, E.*; Girod, S.*; Vlachoudis, V.*; 原田 秀郎; 木村 敦; n_TOF Collaboration*; 他126名*
Nuclear Instruments and Methods in Physics Research A, 799, p.90 - 98, 2015/11
被引用回数：76 パーセンタイル：99.02(Instruments & Instrumentation)At the neutron time-of-flight facility n_TOF at CERN a new vertical beam line was constructed in 2014, in order to extend the experimental possibilities at this facility to an even wider range of challenging cross-section measurements of interest in astrophysics, nuclear technology and medical physics. The design of the beamline and the experimental hall was based on FLUKA Monte Carlo simulations, aiming at maximizing the neutron flux, reducing the beam halo and minimizing the background from neutrons interacting with the collimator or back-scattered in the beam dump. The present paper gives an overview on the design of the beam line and the relevant elements and provides an outlook on the expected performance regarding the neutron beam intensity, shape and energy resolution, as well as the neutron and photon backgrounds.
