Dimitriou, P.*; Dillmann, I.*; Singh, B.*; Piksaikin, V.*; Rykaczewski, K. P.*; Tain, J. L.*; Algora, A.*; Banerjee. K.*; Borzov, I. N.*; Cano-Ott, D.*; et al.
Nuclear Data Sheets, 173, p.144 - 238, 2021/03
-delayed neutron emission has been of interest since the discovery of nuclear fission. In nuclear power reactors, delayed-neutron data play a crucial role in reactor kinetics calculations and safe operation. -delayed neutron data also have a significant impact in the field of nuclear structure and astrophysics especially as nuclei farther away from stability are explored at the new generation of radioactive beam facilities. Several compilations of -decay half-lives and delayed-neutron emission probabilities are available, however, complete documentation of measurements and evaluation procedures is often missing for these properties. Efforts to address this gap in nuclear data and create an updated compilation and evaluation of -delayed neutron properties were undertaken under the auspices of the International Atomic Energy Agency (IAEA) which formed a Coordinated Research Project (CRP) on "Development of a Reference Database of Beta-delayed Neutron Emission Data". In this paper we summarize the work that was performed and present the results of the CRP.
Tsubakihara, Kosuke*; Okumura, Shin*; Ishizuka, Chikako*; Yoshida, Tadashi*; Minato, Futoshi; Chiba, Satoshi*
Journal of Nuclear Science and Technology, 58(2), p.151 - 165, 2021/02
Shizuma, Toshiyuki*; Minato, Futoshi; Omer, M.*; Hayakawa, Takehito*; Ogaki, Hideaki*; Miyamoto, Shuji*
Physical Review C, 103(2), p.024309_1 - 024309_8, 2021/02
Low-lying dipole transitions in Pb were measured via nuclear photon scattering using a quasi-monochromatic, linearly polarized photon beam. The electric () and magnetic () dipole strengths were extracted for excitation energies up to 6.8 MeV. The present (,) results, combined with (,) data from the literature, were used to investigate the and photoabsorption cross sections near the neutron separation energy by comparison with predictions of the particle-vibration coupling on top of the quasi-particle random phase approximation (PVC+QRPA).
Minato, Futoshi; Koura, Hiroyuki
Kaku Deta Nyusu (Internet), (127), p.46 - 62, 2020/10
no abstracts in English
Kaku Deta Nyusu (Internet), (127), p.33 - 37, 2020/10
no abstracts in English
EPJ Web of Conferences, 242, p.05004_1 - 05004_6, 2020/09
We are now developing new decay data using microscopic theoretical models and experimental data newly measured since JENDL/DDF-2015. It includes not only new evaluations of standard decay data information such as half-lives, delayed neutron branching ratios, etc but also theoretically calculated delayed neutron spectra that have not been included in the series of JENDL decay data. We present the detail of the decay data and several results of summation calculation using the decay data and post JENDL/FPY-2011 data produced by TIT group. We also introduce recent theoretical studies for the evaluation of incident neutron energy dependence of fission product yields.
Ciccarelli, M.*; Minato, Futoshi; Naito, Tomoya*
Physical Review C, 102(3), p.034306_1 - 034306_9, 2020/09
Tsukada, Kazuaki; Nagai, Yasuki*; Hashimoto, Shintaro; Minato, Futoshi; Kawabata, Masako*; Hatsukawa, Yuichi*; Hashimoto, Kazuyuki*; Watanabe, Satoshi*; Saeki, Hideya*; Motoishi, Shoji*
Journal of the Physical Society of Japan, 89(3), p.034201_1 - 034201_7, 2020/03
We found anomalously large yields of Ga, Ga, Zn and Cu by neutron irradiation on a ZnO sample in a polyethylene shield. Neutron beams are generated from the Be() reaction for 50 MeV deuterons. The yields obtained were more than 20 times larger than those in the unshielded sample. On the other hand, the yields of Ga, Ga, Zn and Cu from a metallic Zn sample and the yields of Cu, Ni and Zn from the ZnO and Zn samples were almost insensitive to the shield conditions. This finding would provide us a unique capability of accelerator neutrons to simultaneously produce a large amount of several radioisotopes, including proton induced reaction products, by using a single sample. The experimental data were compared with the yields estimated by using the Particle and Heavy Ion Transport code System and the result was discussed.
Minato, Futoshi; Tanimura, Yusuke*
European Physical Journal A, 56(2), p.45_1 - 45_18, 2020/02
For nuclei, three-body model of inert core can provide an understanding of pairing correlations in the ground state and spin-isospin excitations. However, residual core-nucleon interactions can impact the core nucleus significantly. The effect of core excitations thus has to be included for the detailed understanding of the ground state and the spin-isospin properties. We solve the three-body problem including core vibrational states to obtain the ground state as well as the spin-excitations. By including the effect of core excitation, (a) magnetic moment, (b) the enegy difference between the first and the excited states, (c) B(M1) and B(GT), are improved. It was also found that the root mean squares of distances between proton and neutron, and the center of mass of valence prton and neutron and core slightly increase.
Kunieda, Satoshi; Furutachi, Naoya; Minato, Futoshi; Iwamoto, Nobuyuki; Iwamoto, Osamu; Nakayama, Shinsuke; Ebata, Shuichiro*; Yoshida, Toru*; Nishihara, Kenji; Watanabe, Yukinobu*; et al.
Journal of Nuclear Science and Technology, 56(12), p.1073 - 1091, 2019/12
A new nuclear data library, JENDL/ImPACT-2018, is developed for an innovative study on the transmutation of long-lived fission products. Nuclear reaction cross- sections are newly evaluated for incident neutrons and protons up to 200 MeV for 163 nuclides including long-lived nuclei such as Se, Zr, Pd and Cs. Our challenge is an evaluation of cross-sections for a number of unstable nuclei over a wide energy range where the experimental data are very scarce. We estimated cross- sections based on a nuclear model code CCONE that incorporates an advanced knowledge on the nuclear structure theory and a model-parameterization based on a new experimental cross-sections measured by the inverse kinematics. Through comparisons with available experimental data on the stable isotopes, it is found that the present data give predictions of cross-sections better than those in the existing libraries.
Furutachi, Naoya; Minato, Futoshi; Iwamoto, Osamu
Physical Review C, 100(1), p.014610_1 - 014610_7, 2019/07
We investigated the probability distribution of thermal neutron capture cross sections () deduced stochastically with the resonance parameters randomly sampled from Wigner and Porter-Thomas distributions. We found that the typical probability distribution has an asymmetric shape. While there is a long tail on the large side due to a resonance happening to be close to the thermal energy, the multiresonance contribution considerably reduces the probability on the small side. We also found that the probability distributions have a similar shape if nuclei have an average resonance spacing sufficiently larger than an average radiation width. We compared the typical probability distribution with the distribution of the experimental values of 193 nuclei and found a good agreement between them.
Furutachi, Naoya*; Minato, Futoshi; Iwamoto, Osamu
Journal of Nuclear Science and Technology, 56(5), p.412 - 424, 2019/05
A phenomenological level density model that has different level density parameter sets for the state densities of the spherical and the deformed states, and the optimization of the parameters using the experimental data of the average s-wave neutron resonance spacing are presented. The transition to the spherical state from the deformed one is described using the parameters derived from a microscopic nuclear structure calculation. The nuclear reaction calculation has been performed by the statistical model using the present level density. Resulting cross sections for various reactions with the spherical, deformed and transitional target nuclei shows a fair agreement with the experimental data, which indicates the effectiveness of the present model. The role of the rotational collective enhancement in the calculations of those cross sections is also discussed.
Journal of Nuclear Science and Technology, 55(9), p.1054 - 1064, 2018/09
Incident neutron energy dependence of delayed neutron yields of uranium and plutonium isotopes are investigated. A summation calculation of decay and fission yield data is employed, and the energy dependence of the latter part is considered in a phenomenological way. Our calculation systematically reproduces the energy dependence of delayed neutron yields by introducing an energy dependence of the most probable charge and the odd-even effect. We also tested modification of the evaluated fission yield data of the JENDL/FPY-2011 by replacing fission yields of some important delayed neutron precursors with those of the present result. New yield data show improvements in delayed neutron yield, not changing accuracy of the original decay heat calculation.
Tsukada, Kazuaki; Nagai, Yasuki*; Hashimoto, Kazuyuki*; Kawabata, Masako*; Minato, Futoshi; Saeki, Hideya*; Motoishi, Shoji*; Ito, Masatoshi*
Journal of the Physical Society of Japan, 87(4), p.043201_1 - 043201_5, 2018/04
Koura, Hiroyuki; Minato, Futoshi; Iimura, Hideki
Nihon Genshiryoku Gakkai-Shi ATOMO, 60(1), p.35 - 40, 2018/01
no abstracts in English
Minato, Futoshi; Fukui, Tokuro
EPJ Web of Conferences, 163, p.00037_1 - 00037_5, 2017/11
The capture reaction can be divided into two parts, that is the compound and direct processes. For most stable nuclei, the compound process occupies a large part of the neutron capture cross section. However, it has been pointed out that the direct process comes to play a comparable role to the compound one at a low energy in light and neutron-rich nuclei, where the number of resonance state at the neutron threshold energy is relatively small. In addition, there is an interference term between the direct and compound processes. However, it is usually neglected for most nuclei, because either of the compound or the direct process is more important than the other, its contribution becomes negligible. However, some experiment data have given an implication of the existence of the interference effect, and Mengoni and Otsuka reported that the experimental results of capture cross section can be described by taking into account it. It is then natural as a next step to have a concern whether the interference effect comes to play a role for neutron-rich nuclei as well. We therefore calculate the neutron capture reaction for neutron-rich nuclei and study the interference effect on it. We will present some results for neutron-rich nuclei and the interference effect becomes important.
Minato, Futoshi; Tsukada, Kazuaki*; Sato, Nozomi*; Watanabe, Satoshi*; Saeki, Hideya*; Kawabata, Masako*; Hashimoto, Shintaro; Nagai, Yasuki*
Journal of the Physical Society of Japan, 86(11), p.114803_1 - 114803_6, 2017/11
We have measured the yield of Mo, the mother nuclide of Tc used in nuclear diagnostic procedure. Mo was produced by Mo(,)Mo using neutrons with thermal energy up to about 40 MeV, provided by C(,). The Mo yield agrees with an estimated yield with the use of the latest data of C(,) and the evaluated cross section given in the JENDL. Based on this, a new calculation was carried out to produce Mo to seek for a good economical condition. Various conditions such as the MoO sample mass, the distance between the carbon target and the sample, the radius of the deuteron beam, and the neutron irradiation time were considered. The calculated Mo yield indicates that about 30% of the Mo demand in Japan can be fulfilled with a single accelerator. The elusion of Tc from the Mo twice per day would meet about 50% of the Mo demand.
Fukui, Tokuro*; Minato, Futoshi
Physical Review C, 96(5), p.054608_1 - 054608_8, 2017/11
Shizuma, Toshiyuki*; Hayakawa, Takehito*; Daito, Izuru*; Ogaki, Hideaki*; Miyamoto, Shuji*; Minato, Futoshi
Physical Review C, 96(4), p.044316_1 - 044316_10, 2017/10
The low-lying dipole strength in Cr was measured in nuclear resonance fluorescence experiments using a quasi-monochromatic, linearly polarized photon beam. The parities of the excited dipole states were determined by the intensity asymmetry of resonantly scattered -rays with respect to the polarization plane of the incident photon beam. The summed magnetic dipole (M1) strength was determined as at excitation energies between 7.5 and 12.1 MeV; the summed electric dipole (E1) strength was obtained as fm. The observed M1 and E1 strengths were compared via random phase approximation calculations using the Skyrme interaction. The effects of 2 particle-2 hole configuration mixing and tensor force on dipole strength distributions were investigated.