(RE)-Ba-Cu-O bulk superconductors containing non-superconducting phase
inclusions of composition RE
'2411' phase), where M = W, Nb, Ag and Bi, embedded in the REBa
(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
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.
Authors:T. Katabuchi, S. Watanabe, N. Ishioka, Y. Iida, H. Hanaoka, K. Endo and S. Matsuhashi
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%.
Authors:A. Endo, K. Sato, H. Noguchi, Su. Tanaka, T. Iida, S. Furuichi, Y. Kanda and Y. Oki
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.
Authors:S. Watanabe, Y. Iida, N. Suzui, T. Katabuchi, S. Ishii, N. Kawachi, H. Hanaoka, S. Watanabe, S. Matsuhashi, K. Endo and N. Ishioka
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.