Authors:H. Nakahara, K. Sueki, W. Sato, and K. Akiyama
Radiochemical techniques have been applied in various ways to the study of fullerenes and metallofullerenes for the past several years, and they have provided invaluable information pertaining to the stability, structures, and formation of the novel carbon material. This paper reviews those experimental results that have fully shown the usefulness and uniqueness of radionuclides demonstrated in the field of fullerene science.
Authors:K. Sueki, Y. Oura, W. Sato, H. Nakahara, and T. Tomizawa
Nondestructive determination of major and trace elements within voluminous materials has been demonstrated by prompt γ-ray
neutron activation analysis. Some fragmented pieces of pottery bowls considered to have been produced in the late 18th century
were analyzed by a new internal monostandard method, and noticeable differences of the elemental contents and significant
correlations of the elemental distributions were observed among the samples. The possibility of identification of producing
areas of unearthened material is demonstrated by the analytical results and the applicability of this method to the investigation
of precious samples in a completely nondestructive way is verified in practice.
Authors:W. Sato, H. Ueno, A. Taniguchi, Y. Itsuki, Y. Kasamatsu, A. Shinohara, K. Asahi, and Y. Ohkubo
The time-differential perturbed angular correlation (TDPAC) method was applied to a study on the behavior of 140Ce atoms implanted in highly oriented pyrolytic graphite (HOPG). Exponential-type gradual attenuation of the directional anisotropy
of the relevant γ-ray cascade was observed in the perturbation patterns. From temperature dependence of the relaxation rate,
a thermally activated dynamic motion of the probe atoms was suggested.
Authors:H. Nakahara, Y. Oura, K. Sueki, M. Ebihara, W. Sato, Sk. Latif, T. Tomizawa, S. Enomoto, C. Yonezawa, and Y. Ito
An internal monostandard method for PGAA is proposed for completely non-destructive analysis of elements in bulky samples by the use of a neutron beam guided out from the reactor. The method is essentially the same as the k0 method except that it corrects for the change of relative -ray counting efficiencies caused by the absorption and scattering of neutrons and absorption of -rays within the sample. Some examples of applications to archaeological samples of earthen wares, bronze mirrors, and to voluminous meteorite samples are demonstrated, and its future application to the in-situ studies of distribution and metabolism of a certain elements in animals is also explained.
Authors:W. Sato, K. Sueki, K. Kikuchi, K. Kobayashi, S. Suzuki, Y. Achiba, H. Nakahara, Y. Ohkubo, F. Ambe, and K. Asai
Time-differential perturbed angular correlation method was applied to Ce@C82 in order to investigate the electronic properties of the encaged Ce atom. The nuclear quadrupole frequency of the nuclear
spin of the Ce was successfully determined as ωQ = 6.5(3)·107 rad/s, which is much greater than what has already been estimated for Ce4+ and La3+ in other compounds. By comparing the present value with the values for the Ce4+ and La3+, it was inferred that the valence state of the encaged Ce atom is trivalent.
Authors:T. Braun, P. Bull, J. Fardy, I. Haiduc, F. Macasek, W. McDowell, N. Misak, J. Navratil, and T. Sato
Some recent developments in separation techniques with applications to nuclear analytical methods are summarised. The projects discussed are part of an International Atomic Energy Agency Coordinated Research Programme and cover both fundamental studies of the mechanism of various separation processes, and practical applications of novel radiochemical procedures. The processes include methods of sorption, ion exchange and solvent extraction. Applications to neutron activation analysis, photon electron rejecting alpha liquid scintillation spectrometry and X-ray fluorescence spectrometry are described.
Authors:Y. Kobayashi, Y. Tsuruoka, M. Kubo, H. Nonaka, Y. Yamada, Y. Sakai, H. Shoji, W. Sato, A. Shinohara, Y. Watanabe, and H. Matsue
In order to investigate the physical and chemical effects of neutron capture reaction, a neutron in-beam Mössbauer spectroscopic
study on two isomorphs of iron disulfide: pyrite and marcasite, were carried out with a parallel plate avalanche counter at
room temperature. In both compounds only two major products accounted for the obtained spectrum: one with Mössbauer parameters
close to the parent compound and the other one considered to be a new product. The yield of the parent-like species was different
in the two isomorphs.
Authors:Y Kobayashi, M. Kubo, Y. Yamada, T. Saito, H. Ueno, H. Ogawa, W. Sato, K. Yoneda, H. Watanabe, N. Imai, H. Miyoshi, and K. Asahi
In-beam Mössbauer spectra of 57Fe, decayed from short-lived 57Mn (T1/2 = 1.45 min) implanted into potassium permanganate, KMnO4, were measured at temperatures between 11 K and 130 K. This is the first application of a secondary RI beam to the study of valence states after nuclear transformation. The in-beam Mössbauer spectra obtained below 90 K could be analyzed with two components, a doublet and a singlet. From the calculations of the molecular orbital wave functions, the singlet is suggested to be substitutional 57Fe atoms for Mn-sites in tetrahedral [MnO4]– with an unusually high valence state of Fe8+.
Authors:W. Sato, H. Ueno, H. Watanabe, H. Ogawa, H. Miyoshi, N. Imai, A. Yoshimi, K. Yoneda, D. Kameda, Y. Kobayashi, and K. Asahi
A new 19F probe disintegrated from short-lived 19O has been developed for the first time for time-differential perturbed angular correlation method. The angular correlation coefficient for the relevant cascade has been experimentally estimated to be A22 = -0.17±0.01. As the first application of this technique to condensed matter physics, the probe was implanted in polycrystalline fullerene C60. We have observed two contrastive perturbations acting on the probe nuclei, which reflect electrostatic and dynamic interactions with the extranuclear field.
Authors:K. Ninomiya, H. Sugiura, T. Nakatsuka, Y. Kasamatsu, H. Kikunaga, W. Sato, T. Yoshimura, H. Matsumura, K. Takamiya, M. Kubo, K. Sueki, A. Yokoyama, Y. Hamajima, T. Miura, K. Nishiyama, and A. Shinohara
The electronic X-ray energies of muonic atoms were precisely measured. The atomic number (Z) dependence of the energy difference between electronic X-rays of muonic atoms and Z-1 atoms (energy shift) was systematically investigated. The energy shifts in the low-Z region were compared with those of the high-Z region that had been obtained experimentally and theoretically in previous work. An obvious difference between these two
regions was found in the atomic-number dependence of the energy shift. We also compared the energy shifts of muonic atoms
with those of pionic atoms.