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  • Author or Editor: K. Iida x
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Nano-composite (RE)-Ba-Cu-O bulk superconductors containing non-superconducting phase inclusions of composition RE 2 Ba 4 CuMO y (the '2411' phase), where M = W, Nb, Ag and Bi, embedded in the REBa 2 Cu 3 O 7- d (RE-123) superconducting matrix have been fabricated successfully. The 2411-phase has typical dimensions in the range 10-300 nm and is stable under the substitution of any rare earth element on the Y site for all M elements. The 2411-phase is paramagnetic in nature and is characterized by a double perovskite cubic crystallographic structure. All phases within the (RE)-2411 family are chemically inert within the RE-123 matrix and do not coarsen appreciably at elevated temperatures during processing. Most significantly, the (RE)-2411 phase forms effective flux pinning sites within the superconducting matrix, since their size is comparable to that of the coherence length of RE-Ba-Cu-O. A direct correlation between the RE 2 Ba 4 CuMO y phase inclusions content in the RE-123 matrix and increased magnetic flux pinning has been observed. The flux pinning force and the current densities increase by an order of magnitude for the nano-composites compared to that of bulk, melt processed RE-Ba-Cu-O without inclusions, confirming their potential for improved current carrying performance when processed in the form of bulk, thin-film or coated conductors.

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Authors: T. Katabuchi, S. Watanabe, N. Ishioka, Y. Iida, H. Hanaoka, K. Endo and S. Matsuhashi

Abstract  

The radionuclide 67Cu was produced via the 68Zn(p,2p)67Cu reaction by irradiating enriched 68Zn targets with 70 MeV proton beam. Copper-67 was chemically separated from the zinc target by ion-exchange chromatography using Chelex-100 chelating ion-exchange resin. Procedure for recovery of the enriched 68Zn was developed. The target recovery yield of this method was evaluated to be more than 97%.

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Abstract  

The size distributions of 38Cl, 39Cl, 82Br and 84Br aerosols generated by irradiations of argon and krypton gases containing di-octyl phthalate (DOP) aerosols with 45 MeV and 65 MeV quasi-monoenergetic neutrons were measured in order to study the formation mechanism of radioactive particles in high energy radiation fields. The effects of the size distribution of the radioactive aerosols on the size of the added DOP aerosols, the energy of the neutrons and the kinds of nuclides were studied. The observed size distributions of the radioactive particles were explained by attachment of the radioactive atoms generated by the neutron-induced reactions to the DOP aerosols.

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Authors: S. Watanabe, Y. Iida, N. Suzui, T. Katabuchi, S. Ishii, N. Kawachi, H. Hanaoka, S. Watanabe, S. Matsuhashi, K. Endo and N. Ishioka

Abstract  

Copper-64 was produced by the 64Ni(p, n)64Cu reaction using enriched 64NiO target. We investigated and compared the production yield of 64Cu for proton beams of various energies by using a thick target. Enriched 64Ni was recovered with high yield by simple procedures. Imaging studies using positron emission tomography (PET) and positron emitting tracer imaging system (PETIS) were performed. We obtained clear images in PET and PETIS studies. The results of this study indicate that 64Cu can be utilized as a biomedical tracer for the molecular imaging both in animals and plants.

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