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Chen, S.*; Browne, F.*; Doornenbal, P.*; Lee, J.*; Obertelli, A.*; Tsunoda, Yusuke*; Otsuka, Takaharu*; Chazono, Yoshiki*; Hagen, G.*; Holt, J. D.*; et al.
Physics Letters B, 843, p.138025_1 - 138025_7, 2023/08
Times Cited Count:1 Percentile:0.02(Astronomy & Astrophysics)Gamma decays were observed in Ca and Ca following quasi-free one-proton knockout reactions from Sc. For Ca, a ray transition was measured to be 1456(12) keV, while for Ca an indication for a transition was observed at 1115(34) keV. Both transitions were tentatively assigned as the decays. A shell-model calculation in a wide model space with a marginally modified effective nucleon-nucleon interaction depicts excellent agreement with experiment for level energies, two-neutron separation energies, and reaction cross sections, corroborating the formation of a new nuclear shell above the N = 34 shell. Its constituents, the and orbitals, are almost degenerate. This degeneracy precludes the possibility for a doubly magic Ca and potentially drives the dripline of Ca isotopes to Ca or even beyond.
Rodriguez, D.; Abbas, K.*; Bertolotti, D.*; Bonaldi, C.*; Fontana, C.*; Fujimoto, Masami*; Geerts, W.*; Koizumi, Mitsuo; Macias, M.*; Nonneman, S.*; et al.
Proceedings of INMM & ESARDA Joint Annual Meeting 2023 (Internet), 8 Pages, 2023/05
Elekes, Z.*; Juhsz, M. M.*; Sohler, D.*; Sieja, K.*; Yoshida, Kazuki; Ogata, Kazuyuki*; Doornenbal, P.*; Obertelli, A.*; Achouri, N. L.*; Baba, Hidetada*; et al.
Physical Review C, 106(6), p.064321_1 - 064321_10, 2022/12
Times Cited Count:2 Percentile:0.02(Physics, Nuclear)The low-lying level structure of V and V was investigated for the first time. The neutron knockout reaction and inelastic proton scattering were applied for V while the neutron knock-out reaction provided the data for V. Four and five new transitions were determined for V and V, respectively. Based on the comparison to our shell-model calculations using the Lenzi-Nowacki-Poves-Sieja (LNPS) interaction, three of the observed rays for each isotope could be placed in the level scheme and assigned to the decay of the first 11/2 and 9/2 levels. The (,) excitation cross sections for V were analyzed by the coupled-channels formalism assuming quadrupole plus hexadecapole deformations. Due to the role of the hexadecapole deformation, V could not be unambiguously placed on the island of inversion.
Enciu, M.*; Liu, H. N.*; Obertelli, A.*; Doornenbal, P.*; Nowacki, F.*; Ogata, Kazuyuki*; Poves, A.*; Yoshida, Kazuki; Achouri, N. L.*; Baba, Hidetada*; et al.
Physical Review Letters, 129(26), p.262501_1 - 262501_7, 2022/12
Times Cited Count:4 Percentile:46.35(Physics, Multidisciplinary)The one-neutron knockout from Ca was performed at 230 MeV/nucleon combined with prompt spectroscopy. The momentum distributions corresponding to the removal of and neutrons were measured. The cross sections are consistent with a shell closure at the neutron number , found as strong as at and in Ca isotopes from the same observables. The analysis of the momentum distributions leads to a difference of the root-mean-square radii of the neutron and orbitals of 0.61(23) fm, in agreement with the modified-shell-model prediction of 0.7 fm suggesting that the large root-mean-square radius of the orbital in neutron-rich Ca isotopes is responsible for the unexpected linear increase of the charge radius with the neutron number.
Koiwai, Takuma*; Wimmer, K.*; Doornenbal, P.*; Obertelli, A.*; Barbieri, C.*; Duguet, T.*; Holt, J. D.*; Miyagi, Takayuki*; Navrtil, P.*; Ogata, Kazuyuki*; et al.
Physics Letters B, 827, p.136953_1 - 136953_7, 2022/04
Times Cited Count:4 Percentile:52.69(Astronomy & Astrophysics)no abstracts in English
Linh, B. D.*; Corsi, A.*; Gillibert, A.*; Obertelli, A.*; Doornenbal, P.*; Barbieri, C.*; Chen, S.*; Chung, L. X.*; Duguet, T.*; Gmez-Ramos, M.*; et al.
Physical Review C, 104(4), p.044331_1 - 044331_16, 2021/10
Times Cited Count:5 Percentile:46.8(Physics, Nuclear)no abstracts in English
Browne, F.*; Chen, S.*; Doornenbal, P.*; Obertelli, A.*; Ogata, Kazuyuki*; Utsuno, Yutaka; Yoshida, Kazuki; Achouri, N. L.*; Baba, Hidetada*; Calvet, D.*; et al.
Physical Review Letters, 126(25), p.252501_1 - 252501_7, 2021/06
Times Cited Count:10 Percentile:69.3(Physics, Multidisciplinary)Direct proton-knockout reactions of Sc were studied at the RIKEN Radioactive Isotope Beam Factory. Populated states of Ca were investigated through -ray and invariant-mass spectroscopy. Level energies were calculated from the nuclear shell model employing a phenomenological inter-nucleon interaction. Theoretical cross sections to states were calculated from distorted-wave impulse approximation estimates multiplied by the shell model spectroscopic factors. Despite the calculations showing a significant amplitude of excited neutron configurations in the ground-state of Sc, valence proton removals populated predominantly the ground-state of Ca. This counter-intuitive result is attributed to pairing effects leading to a dominance of the ground-state spectroscopic factor. Owing to the ubiquity of the pairing interaction, this argument should be generally applicable to direct knockout reactions from odd-even to even-even nuclei.
Juhsz, M. M.*; Elekes, Z.*; Sohler, D.*; Utsuno, Yutaka; Yoshida, Kazuki; Otsuka, Takaharu*; Ogata, Kazuyuki*; Doornenbal, P.*; Obertelli, A.*; Baba, Hidetada*; et al.
Physics Letters B, 814, p.136108_1 - 136108_8, 2021/03
Times Cited Count:5 Percentile:46.8(Astronomy & Astrophysics)The nuclear structure of Ar was studied by the (,2) reaction using -ray spectroscopy for the bound and unbound states. Comparing the results to our shell-model calculations, two bound and six unbound states were established. The low cross sections populating the two bound states of Ar could be interpreted as a clear signature for the presence of significant sub-shell closures at neutron numbers 32 and 34 in argon isotopes.
Corts, M. L.*; Rodriguez, W.*; Doornenbal, P.*; Obertelli, A.*; Holt, J. D.*; Menndez, J.*; Ogata, Kazuyuki*; Schwenk, A.*; Shimizu, Noritaka*; Simonis, J.*; et al.
Physical Review C, 102(6), p.064320_1 - 064320_9, 2020/12
Times Cited Count:11 Percentile:73.66(Physics, Nuclear)Low-lying excited states in the = 32 isotope Ar were investigated by in-beam -ray spectroscopy following proton- and neutron-knockout, multinucleon removal, and proton inelastic scattering at the RIKEN Radioactive Isotope Beam Factory. The energies of the two previously reported transitions have been confirmed, and five additional states are presented for the first time, including a candidate for a 3 state. The level scheme built using coincidences was compared to shell-model calculations in the model space and to predictions based on chiral two- and three-nucleon interactions. Theoretical proton- and neutron-knockout cross sections suggest that two of the new transitions correspond to 2 states, while the previously proposed 4 state could also correspond to a 2 state.
Corts, M. L.*; Rodriguez, W.*; Doornenbal, P.*; Obertelli, A.*; Holt, J. D.*; Lenzi, S. M.*; Menndez, J.*; Nowacki, F.*; Ogata, Kazuyuki*; Poves, A.*; et al.
Physics Letters B, 800, p.135071_1 - 135071_7, 2020/01
Times Cited Count:31 Percentile:96.23(Astronomy & Astrophysics)Excited states in the = 40 isotone Ti were populated via the V(,)Ti reaction at 200 MeV/nucleon at the Radioactive Isotope Beam Factory and studied using -ray spectroscopy. The energies of the and transitions, observed here for the first time, indicate a deformed Ti ground state. These energies are increased compared to the neighboring Cr and Fe isotones, suggesting a small decrease of quadrupole collectivity. The present measurement is well reproduced by large-scale shell-model calculations based on effective interactions, while ab initio and beyond mean-field calculations do not yet reproduce our findings.
Chen, S.*; Lee, J.*; Doornenbal, P.*; Obertelli, A.*; Barbieri, C.*; Chazono, Yoshiki*; Navrtil, P.*; Ogata, Kazuyuki*; Otsuka, Takaharu*; Raimondi, F.*; et al.
Physical Review Letters, 123(14), p.142501_1 - 142501_7, 2019/10
Times Cited Count:47 Percentile:92.65(Physics, Multidisciplinary)no abstracts in English
Rodriguez, P.; Senzaki, Masao; Sekine, Megumi
Proceedings of INMM 60th Annual Meeting (Internet), 9 Pages, 2019/07
The ISCN of the JAEA has been providing assistance, specifically to Asian countries, for the past 8 years, since its establishment in 2010. The ratification of the Protocol Additional (AP) to the safeguards agreement, had involved some changes in the Asian countries resource infrastructures to adhere with the respective States obligations on nuclear non-proliferation. During the 7th FNCA workshop held in Mito, Japan in September 2017, under the Nuclear Security and Safegaurds Project (NSSP), a 3-year plan on the formulation of a generic set of Fundamentals on the Implementation of the Additional Protocol was proposed. To formulate this set of fundamentals, there was a need to prepare a set of Examples of good practices on the implementation of the AP based on the FNCA members experience. The ISCN was tasked to prepare the template and conduct the needed survey among the FNCA members of the project on nuclear security and safeguards. This paper provides a preliminary summary and analysis of the responses received. This paper presents the analysis of the good practices that were implemented in order for the States to satisfy the requirements of the IAEA, as stipulated in the AP. The nuclear fuel cycle characteristics of the involved Asian countries are quite different in several aspects, thus entailing a diverse strategy in resource infrastructure development. This paper describes how every country may have different approaches towards achieving the same objectives. It is worthwhile to look into these various practices, find commonality and share the experience. The objective of formulating a set of fundamentals on AP implementation will be achieved through a compilation and analysis of good practices and shared experiences among its members. The preliminary result on this project was introduced at the 8th FNCA workshop held in Beijing, China in September 2018.
Miyaji, Noriko; Vidaurre, J.; Hori, Masato; Rodriguez, P.; Robertson, K.*
Proceedings of IAEA Symposium on International Safeguards; Building Future Safeguards Capabilities (Internet), 5 Pages, 2018/11
Koizumi, Mitsuo; Rossi, F.; Rodriguez, D.; Takamine, Jun; Seya, Michio; Bogucarska, T.*; Crochemore, J.-M.*; Varasano, G.*; Abbas, K.*; Pedersen, B.*; et al.
EPJ Web of Conferences, 146, p.09018_1 - 09018_4, 2017/09
Times Cited Count:3 Percentile:86.43(Nuclear Science & Technology)Flavigny, F.*; Doornenbal, P.*; Obertelli, A.*; Delaroche, J.-P.*; Girod, M.*; Libert, J.*; Rodriguez, T. R.*; Authelet, G.*; Baba, Hidetada*; Calvet, D.*; et al.
Physical Review Letters, 118(24), p.242501_1 - 242501_6, 2017/06
Times Cited Count:38 Percentile:86.73(Physics, Multidisciplinary)Chen, S.*; Doornenbal, P.*; Obertelli, A.*; Rodriguez, T. R.*; Authelet, G.*; Baba, Hidetada*; Calvet, D.*; Chteau, F.*; Corsi, A.*; Delbart, A.*; et al.
Physical Review C, 95(4), p.041302_1 - 041302_6, 2017/04
Times Cited Count:26 Percentile:88.02(Physics, Nuclear)Koizumi, Mitsuo; Rossi, F.; Rodriguez, D.; Takamine, Jun; Seya, Michio; Bogucarska, T.*; Crochemore, J.-M.*; Varasano, G.*; Abbas, K.*; Pedersen, B.*; et al.
EUR-28795-EN (Internet), p.868 - 872, 2017/00
Koizumi, Mitsuo; Heyse, J.*; Mondelaers, W.*; Paradela, C.*; Pedersen, B.*; Schillebeeckx, P.*; Seya, Michio; Rodriguez, D.; Takamine, Jun
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-36-Kai Nenji Taikai Rombunshu (Internet), 6 Pages, 2015/12
The fission-product yield distributions are unique for each fissionable nuclide and interrogating neutron energy. Ratios of fissile materials (e.g. U, Pu, and Pu), therefore, could be deduced from differences in the observed neutron-induced Delayed Gamma-ray (DG) spectra characterized by the difference of these yields. This DG Spectroscopy (DGS) project includes research and development of a measurement system along with confirming and improving nuclear data. Experiments will be held at multiple facilities, including ITU/Ispra (Italy), IRMM/Geel (Belgium), and KURRI/Kumatori (Japan), using a wide range of neutron sources and nuclear material sample targets. The experimental efforts of this DGS project are described in this presentation.
Rodriguez, D.; Heyse, J.*; Koizumi, Mitsuo; Mondelaers, W.*; Pedersen, B.*; Schillebeeckx, P.*; Seya, Michio; Takamine, Jun
Proceedings of INMM 56th Annual Meeting (Internet), 8 Pages, 2015/07
There is a growing interest regarding how to effectively safeguard NM, specifically how to efficiently determine the composition of mixed materials. Currently researchers of the JAEA and JRC are discussing the development of a NDA system using a pulsed DT neutron source. The system will utilize a combination of DDA, NRTA, PGA, and DGS techniques. Of specific interest is applying this system toward determining the Pu/U composition of purified MOX fuel and non-purified NM. The DGS technique has the potential to establish fissionable material ratios to relatively high precision. These fission products generate time-dependent -ray energy spectra that extend well above 3 MeV, a benefit when applied to the NM of interest that have high passive emissions. This presentation will describe initial studies regarding the precision that the DGS portion of this system can obtain and how it will be used in conjunction with the other techniques to analyze the composition of the NM of interest.
MacDougall, G. J.*; Savici, A. T.*; Aczel, A. A.*; Birgeneau, R. J.*; Kim, H.*; Kim, S.-J.*; Ito, Toshimitsu*; Rodriguez, J. A.*; Russo, P. L.*; Uemura, Yasutomo*; et al.
Physical Review B, 81(1), p.014508_1 - 014508_7, 2010/01
Times Cited Count:11 Percentile:46.11(Materials Science, Multidisciplinary)