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H Baba - One of the best experts on this subject based on the ideXlab platform.
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β decay half lives of 55 neutron rich Isotopes beyond the n 82 shell gap
Physical Review C, 2020Co-Authors: S Nishimura, Peter Moller, H Baba, M R Mumpower, R Lozeva, C B Moon, A Odahara, F Browne, R DaidoAbstract:The $\beta$-decay half-lives of 55 neutron-rich nuclei $^{134-139}$Sn, $^{134-142}$Sb, $^{137-144}$Te, $^{140-146}$I, $^{142-148}$Xe, $^{145-151}$Cs, $^{148-153}$Ba, $^{151-155}$La were measured at the Radioactive Isotope Beam Factory (RIBF) employing the projectile fission fragments of $^{238}$U. The nuclear level structure, which relates to deformation, has a large effect on the half-lives. The impact of newly-measured half-lives on modeling the astrophysical origin of the heavy elements is studied in the context of $r$ process nucleosynthesis. For a wide variety of astrophysical conditions, including those in which fission recycling occurs, the half-lives have an important local impact on the second ($A$ $\approx$ 130) peak.
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magic nature of neutrons in 54 ca first mass measurements of 55 57 ca
Physical Review Letters, 2018Co-Authors: S Michimasa, N Fukuda, H Baba, M Kobayashi, Y Kiyokawa, Shuichi Ota, D S Ahn, G P A Berg, M Dozono, T FurunoAbstract:We perform the first direct mass measurements of neutron-rich calcium Isotopes beyond neutron number 34 at the RIKEN Radioactive Isotope Beam Factory by using the time-of-flight magnetic-rigidity technique. The atomic mass excesses of ^{55-57}Ca are determined for the first time to be -18650(160), -13510(250), and -7370(990) keV, respectively. We examine the emergence of neutron magicity at N=34 based on the new atomic masses. The new masses provide experimental evidence for the appearance of a sizable energy gap between the neutron 2p_{1/2} and 1f_{5/2} orbitals in ^{54}Ca, comparable to the gap between the neutron 2p_{3/2} and 2p_{1/2} orbitals in ^{52}Ca. For the ^{56}Ca nucleus, an open-shell property in neutrons is suggested.
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94 β decay half lives of neutron rich 55cs to 67ho experimental feedback and evaluation of the r process rare earth peak formation
Physical Review Letters, 2017Co-Authors: S Nishimura, G Lorusso, P H Regan, Peter Moller, E Ideguchi, G S Simpson, P A Soderstrom, P M Walker, H Watanabe, H BabaAbstract:the beta-decay half-lives of 94 neutron-rich nuclei 144-151Cs; 146-155Ba; 148-156La; 150-158Ce; 153-160Pr; 156-162Nd; 159-163Pm; 160-166Sm; 161-168eu; 165-170Gd, 166-172Tb; 169-173Dy; 172-175Ho, and 2 isomeric states 174mEr and 172mDy were measured at the Radioactive Isotope Beam Factory providing a new experimental basis to test theoetical models. Strikingl large drops of beta-decay half-lives are observed at neutron-number N=97 for Ce, Pr, Nd and Sm and N=105 for eu, Gd, Tb and Dy.
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nucleus 26 o a barely unbound system beyond the drip line
Physical Review Letters, 2016Co-Authors: Y Kondo, H Baba, T Nakamura, R Tanaka, R Minakata, S Ogoshi, N A Orr, N L Achouri, T Aumann, F DelaunayAbstract:The unbound nucleus ^{26}O has been investigated using invariant-mass spectroscopy following one-proton removal reaction from a ^{27}F beam at 201 MeV/nucleon. The decay products, ^{24}O and two neutrons, were detected in coincidence using the newly commissioned SAMURAI spectrometer at the RIKEN Radioactive Isotope Beam Factory. The ^{26}O ground-state resonance was found to lie only 18±3(stat)±4(syst) keV above threshold. In addition, a higher lying level, which is most likely the first 2^{+} state, was observed for the first time at 1.28_{-0.08}^{+0.11} MeV above threshold. Comparison with theoretical predictions suggests that three-nucleon forces, pf-shell intruder configurations, and the continuum are key elements to understanding the structure of the most neutron-rich oxygen Isotopes beyond the drip line.
S Nishimura - One of the best experts on this subject based on the ideXlab platform.
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determination of beta delayed neutron emission probability limits of rhodium Isotopes by gamma ray spectroscopy
27th International Nuclear Physics Conference INPC 2019, 2020Co-Authors: R Shearman, G Lorusso, A Boso, P H Regan, S Nishimura, A Jungclaus, Y ShimizuAbstract:The decay of five neutron-heavy rhodium Isotopes were studied at the Radioactive Isotope Beam Factory (RIBF) Facility at the RIKEN Nishina Center after relativistic fission of 238U beam on a thick beryllium target. Previously unknown associated gamma-ray decay energies are reported for each nuclide, and through evaluating the intensity of the 2+ → 0+ E2 transition in the even-even palladium daughter nuclei, 120,122,124Pd, from the beta-tagged gamma-ray spectra an upper or lower limit of beta-delayed neutron emission is deduced for each nuclei. A general, expected trend of increasing Pn is observed in the direction of the neutron drip line
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β decay half lives of 55 neutron rich Isotopes beyond the n 82 shell gap
Physical Review C, 2020Co-Authors: S Nishimura, Peter Moller, H Baba, M R Mumpower, R Lozeva, C B Moon, A Odahara, F Browne, R DaidoAbstract:The $\beta$-decay half-lives of 55 neutron-rich nuclei $^{134-139}$Sn, $^{134-142}$Sb, $^{137-144}$Te, $^{140-146}$I, $^{142-148}$Xe, $^{145-151}$Cs, $^{148-153}$Ba, $^{151-155}$La were measured at the Radioactive Isotope Beam Factory (RIBF) employing the projectile fission fragments of $^{238}$U. The nuclear level structure, which relates to deformation, has a large effect on the half-lives. The impact of newly-measured half-lives on modeling the astrophysical origin of the heavy elements is studied in the context of $r$ process nucleosynthesis. For a wide variety of astrophysical conditions, including those in which fission recycling occurs, the half-lives have an important local impact on the second ($A$ $\approx$ 130) peak.
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94 β decay half lives of neutron rich 55cs to 67ho experimental feedback and evaluation of the r process rare earth peak formation
Physical Review Letters, 2017Co-Authors: S Nishimura, G Lorusso, P H Regan, Peter Moller, E Ideguchi, G S Simpson, P A Soderstrom, P M Walker, H Watanabe, H BabaAbstract:the beta-decay half-lives of 94 neutron-rich nuclei 144-151Cs; 146-155Ba; 148-156La; 150-158Ce; 153-160Pr; 156-162Nd; 159-163Pm; 160-166Sm; 161-168eu; 165-170Gd, 166-172Tb; 169-173Dy; 172-175Ho, and 2 isomeric states 174mEr and 172mDy were measured at the Radioactive Isotope Beam Factory providing a new experimental basis to test theoetical models. Strikingl large drops of beta-decay half-lives are observed at neutron-number N=97 for Ce, Pr, Nd and Sm and N=105 for eu, Gd, Tb and Dy.
Ram S. Lokhande - One of the best experts on this subject based on the ideXlab platform.
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Application of Br-82 as a Radioactive tracer Isotope to study bromide ion-isotopic exchange reaction in strongly basic anion exchange resin Duolite A-161
Russian Journal of Physical Chemistry A, 2009Co-Authors: Ram S. Lokhande, P. U. Singare, S. R. D. TiwariAbstract:In the present investigation Br-82 Radioactive Isotope was used as a tracer to study the kinetics of exchange reaction taking place between the ion exchange resin and the external bromide ion solution. In an attempt to study the reversible bromide ion-isotopic exchange reaction kinetics, it was expected that whether the initial step was the exchange of Radioactive bromide ions from the solution on to the ion exchange resin (forward reaction), or from the ion exchange resin in to the solution (reverse reaction), the two ion-isotopic exchange reactions should occur simultaneously, which was further confirmed from the values of specific reaction rate 0.122 and 0.123 min^−1 respectively obtained under identical experimental conditions. The Radioactive tracer technique employed in the present investigation will be useful for characterization of various industrial grade ion exchange resins.
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the application of the Radioactive tracer technique to study the kinetics of bromide Isotope exchange reaction with the participation of strongly basic anion exchange resin indion ff ip
Russian Journal of Physical Chemistry A, 2008Co-Authors: Ram S. Lokhande, P. U. Singare, T S PrabhavalkarAbstract:In the present investigation, the 82Br Radioactive Isotope was used as a tracer to study the kinetics and mechanism of the exchange reaction between an ion exchange resin and an external solution of bromide ions. In an attempt to study the reversible bromide Isotope exchange reaction kinetics, it was expected that whether the initial step was the exchange of Radioactive bromide ions from the solution to the ion exchange resin (forward reaction) or from the ion exchange resin to the solution (reverse reaction), the two ion-Isotope exchange reactions should occur simultaneously, which was further confirmed by the experimental values of specific reaction rates, 0.142 and 0.141 min−1, respectively. The results will be useful to standardize the process parameters so as to achieve optimum use of ion exchange resins in various industrial applications.
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the kinetics and mechanism of bromide ion Isotope exchange reaction in strongly basic anion exchange resin duolite a 162 determined by the Radioactive tracer technique
Russian Journal of Physical Chemistry A, 2007Co-Authors: Ram S. Lokhande, P. U. Singare, P KarthikeyanAbstract:In the present investigation, 82Br Radioactive Isotope was used as a tracer to study the kinetics and mechanism of exchange reaction between an ion exchange resin and an external bromide ion solution. In an attempt to study the reversible bromide ion isotopic exchange reaction kinetics, it was expected that whether the initial step was the exchange of Radioactive bromide ions from the solution into the ion exchange resin (forward reaction) or from the ion exchange resin into the solution (reverse reaction), two ion isotopic exchange reactions should occur simultaneously, which was further confirmed by the experimental specific reaction rates of 0.130 and 0.131 min−1, respectively. The results can be used to standardize process parameters so as to optimize the utilization of ion exchange resins in various industrial applications.
N Fukuda - One of the best experts on this subject based on the ideXlab platform.
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magic nature of neutrons in 54 ca first mass measurements of 55 57 ca
Physical Review Letters, 2018Co-Authors: S Michimasa, N Fukuda, H Baba, M Kobayashi, Y Kiyokawa, Shuichi Ota, D S Ahn, G P A Berg, M Dozono, T FurunoAbstract:We perform the first direct mass measurements of neutron-rich calcium Isotopes beyond neutron number 34 at the RIKEN Radioactive Isotope Beam Factory by using the time-of-flight magnetic-rigidity technique. The atomic mass excesses of ^{55-57}Ca are determined for the first time to be -18650(160), -13510(250), and -7370(990) keV, respectively. We examine the emergence of neutron magicity at N=34 based on the new atomic masses. The new masses provide experimental evidence for the appearance of a sizable energy gap between the neutron 2p_{1/2} and 1f_{5/2} orbitals in ^{54}Ca, comparable to the gap between the neutron 2p_{3/2} and 2p_{1/2} orbitals in ^{52}Ca. For the ^{56}Ca nucleus, an open-shell property in neutrons is suggested.
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spallation reaction study for fission products in nuclear waste cross section measurements for 137cs 90sr and 107pd on proton and deuteron
2016 International Conference on Nuclear Data for Science and Technology ND 2016, 2017Co-Authors: H Wang, H Otsu, H Sakurai, Masayuki Aikawa, P Doornenbal, T Ando, Shouhei Araki, Sidong Chen, N Chiga, N FukudaAbstract:Spallation reactions for the long-lived fission products 137 Cs, 90 Sr and 107 Pd have been studied for the purpose of nuclear waste transmutation. The cross sections on the proton- and deuteron-induced spallation were obtained in inverse kinematics at the RIKEN Radioactive Isotope Beam Factory. Both the target and energy dependences of cross sections have been investigated systematically. and the cross-section differences between the proton and deuteron are found to be larger for lighter fragments. The experimental data are compared with the SPACS semi-empirical parameterization and the PHITS calculations including both the intra-nuclear cascade and evaporation processes.
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spallation reaction study for the long lived fission products in nuclear waste cross section measurements for 137cs 90sr and 107pd using inverse kinematics method
Energy Procedia, 2017Co-Authors: H Wang, H Otsu, H Sakurai, P Doornenbal, N Fukuda, T Isobe, T Kubo, N Chiga, S Kubono, Giusseppe LorussoAbstract:Abstract Spallation reaction study has been performed for the long-lived fission products 137Cs, 90Sr and 107Pd. Isotopic cross sections on proton and deuteron were obtained by using the inverse kinematics technique at the RIKEN Radioactive Isotope Beam Factory. It was found that the deuteron-induced cross sections are larger than the proton-induced ones for the light-mass products. The experimental data were compared with the SPACS semi-empirical parameterization and a theoretical calculation including both the intra-nuclear cascade and evaporation models by the PHITS transport code. It was found that the spallation reaction could be a promising mechanism for the transmutation of 137Cs and 90Sr due to the large total cross section.
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spallation reaction study for fission products in nuclear waste cross section measurements for 137cs and 90sr on proton and deuteron
Physics Letters B, 2016Co-Authors: H Wang, H Otsu, H Sakurai, Masayuki Aikawa, P Doornenbal, N Fukuda, T Isobe, S Kawakami, S Koyama, T KuboAbstract:Abstract We have studied spallation reactions for the fission products 137 Cs and 90 Sr for the purpose of nuclear waste transmutation. The spallation cross sections on the proton and deuteron were obtained in inverse kinematics for the first time using secondary beams of 137 Cs and 90 Sr at 185 MeV/nucleon at the RIKEN Radioactive Isotope Beam Factory. The target dependence has been investigated systematically, and the cross-section differences between the proton and deuteron are found to be larger for lighter spallation products. The experimental data are compared with the PHITS calculation, which includes cascade and evaporation processes. Our results suggest that both proton- and deuteron-induced spallation reactions are promising mechanisms for the transmutation of Radioactive fission products.
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identification of new Isotopes 125 pd and 126 pd produced by in flight fission of 345 mev nucleon 238 u first results from the riken ri beam factory
Journal of the Physical Society of Japan, 2008Co-Authors: Tetsuya Ohnishi, N Fukuda, T Kubo, K Kusaka, A Yoshida, K Yoshida, M Ohtake, Y Yanagisawa, Hiroyuki Takeda, Daisuke KamedaAbstract:A search for new Isotopes using in-flight fission of a 345 MeV/nucleon 238 U beam has been carried out in the commissioning experiment of the next-generation in-flight Radioactive Isotope beam separator BigRIPS at the RI Beam Factory at the RIKEN Nishina Center. Two neutron-rich palladium Isotopes 125 Pd and 126 Pd were observed for the first time, which demonstrates the great potential of the RIKEN RI beam factory.
H Wang - One of the best experts on this subject based on the ideXlab platform.
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Spallation reaction study for long-lived fission products in nuclear waste
'EDP Sciences', 2020Co-Authors: H Wang, H Otsu, H Sakurai, Masayuki Aikawa, T Ando, Shouhei Araki, Sidong Chen, N Chiga, Deuksoon Ahn, P DoornenbalAbstract:Spallation reaction for the long-lived fission product 107Pd has been studied for the purpose of nuclear waste transmutation. The isotopic-distribution cross sections on both proton and deuteron were obtained at 118 MeV/nucleon in inverse kinematics at the RIKEN Radioactive Isotope Beam Factory. A large cross-section difference was found between the proton and deuteron results for the light-mass products. The data were compared with the SPACS semi-empirical parameterization and the PHITS calculations including both the intranuclear cascade and evaporation processes. In addition, the potential of spallation reaction for transmutation of 107Pd is discussed
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spallation reaction study for fission products in nuclear waste cross section measurements for 137cs 90sr and 107pd on proton and deuteron
2016 International Conference on Nuclear Data for Science and Technology ND 2016, 2017Co-Authors: H Wang, H Otsu, H Sakurai, Masayuki Aikawa, P Doornenbal, T Ando, Shouhei Araki, Sidong Chen, N Chiga, N FukudaAbstract:Spallation reactions for the long-lived fission products 137 Cs, 90 Sr and 107 Pd have been studied for the purpose of nuclear waste transmutation. The cross sections on the proton- and deuteron-induced spallation were obtained in inverse kinematics at the RIKEN Radioactive Isotope Beam Factory. Both the target and energy dependences of cross sections have been investigated systematically. and the cross-section differences between the proton and deuteron are found to be larger for lighter fragments. The experimental data are compared with the SPACS semi-empirical parameterization and the PHITS calculations including both the intra-nuclear cascade and evaporation processes.
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spallation reaction study for the long lived fission products in nuclear waste cross section measurements for 137cs 90sr and 107pd using inverse kinematics method
Energy Procedia, 2017Co-Authors: H Wang, H Otsu, H Sakurai, P Doornenbal, N Fukuda, T Isobe, T Kubo, N Chiga, S Kubono, Giusseppe LorussoAbstract:Abstract Spallation reaction study has been performed for the long-lived fission products 137Cs, 90Sr and 107Pd. Isotopic cross sections on proton and deuteron were obtained by using the inverse kinematics technique at the RIKEN Radioactive Isotope Beam Factory. It was found that the deuteron-induced cross sections are larger than the proton-induced ones for the light-mass products. The experimental data were compared with the SPACS semi-empirical parameterization and a theoretical calculation including both the intra-nuclear cascade and evaporation models by the PHITS transport code. It was found that the spallation reaction could be a promising mechanism for the transmutation of 137Cs and 90Sr due to the large total cross section.
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spallation reaction study for fission products in nuclear waste cross section measurements for 137cs and 90sr on proton and deuteron
Physics Letters B, 2016Co-Authors: H Wang, H Otsu, H Sakurai, Masayuki Aikawa, P Doornenbal, N Fukuda, T Isobe, S Kawakami, S Koyama, T KuboAbstract:Abstract We have studied spallation reactions for the fission products 137 Cs and 90 Sr for the purpose of nuclear waste transmutation. The spallation cross sections on the proton and deuteron were obtained in inverse kinematics for the first time using secondary beams of 137 Cs and 90 Sr at 185 MeV/nucleon at the RIKEN Radioactive Isotope Beam Factory. The target dependence has been investigated systematically, and the cross-section differences between the proton and deuteron are found to be larger for lighter spallation products. The experimental data are compared with the PHITS calculation, which includes cascade and evaporation processes. Our results suggest that both proton- and deuteron-induced spallation reactions are promising mechanisms for the transmutation of Radioactive fission products.
