The retentions of cobalt, copper and zinc recoils were studied in the mixed crystal system of -cobalt phthalocyanine and -zinc phthalocyanine. It was suggested that a part of the retentions of cobalt and zinc recoils was due to a competitive process. The relationship between the retentions of the zinc recoils and their recoil energy in different matrices was discussed.
Aerosol-size distributions of218Po were determined for the accelerator tunnel air sampled during machine operation and for the basement air of a concrete
building, where the number and the size distribution of non-radioactive aerosols are greatly different from each other. The218Po distributions depended very much on the size distributions of ambient non-radioactive aerosols, and could be well explained
by an attachment model of218Po to ambient non-radioactive aerosols.
Authors:H. Shoji, Y. Maruyama, K. Ogawa, Y. Oki, and N. Ikeda
A series of metal -diketonates were irradiated with bremsstrahlung of maximum energy of 50 MeV and the recoil behavior of7Be, formed from12C of ligands through12C(, n)7Be reaction, was investigated.7Be nuclides thus formed were detected partially as central metal atoms of the complexes. Complex yields of7Be were compared and an anomalously high yield was observed in tris-acetylacetonatocobalt(III) [Co(acac)3].
Authors:Y. Igarashi, A. Yamakawa, Y. Oki, R. Seki, and N. Ikeda
Uranium in Japanese tobacco leaves and in Japanese human hair was determined by the fission track method. It was found that the uranium content in smokers' hair was higher than that in non-smokers' one and a part of uranium was lost from tobacco leaves by ashing at 500–700 °C. These two results suggest that uranium would be inhaled through smoking.
Authors:Y. Kanda, Y. Oki, A. Endo, M. Numajiri, and K. Kondo
The irradiation of atmospheric air with high-energy protons has been performed at the 12 GeV proton synchrotron. The specific activity of 13N, one of the principal airborne radioactivities, was measured as a function of the irradiation time at a dose rate of about 6·1016 eV/g/s, and compared with the calculated values. The predominant chemical species of 13N produced were found to be 13N2and 13NO2. Their proportions were approximately 55% for 13N2 and 45% for13NO2, being almost independent of the irradiation time. Smaller quantities of 13NO and H13NO2 were also observed. Measurements of radiolytic products showed that ozone is a main product and that NO2predominates among the products of nitrogen compounds, including HNO2 and HNO3. The G-value for ozone formation in air was estimated from the experimental data as 6.4 molecules/100 eV.
The chemical effect of7Be recoils formed through a12C/, n/7Be process from ligand carbon atoms was investigated in a several phthalocyanines. It was found that7Be-phthalocyanine was synthesized by7Be recoil. Net radiochemical yields of7Be-phthalocyanine were estimated to be 10–20% for copper and zinc phthalocyanines, while for metal-free phthalocyanines, yields above 90% were obtained.
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:M. Numajiri, K. Masumoto, T. Miura, Y. Oki, T. Suzuki, and K. Kondo
Although the estimation of 14C radioactivity is very important from a radiation safety viewpoint at high-intensity and high-energy accelerator facilities, it is very difficult, since there is little information concerning the production cross sections by high-energy nuclear reactions. In this work, the 14C production cross section was measured for the nuclear spallation reaction of aluminum with 12-GeV protons. The chemical separation method of 14C was also studied.
Authors:T. Suzuki, Y. Oki, M. Numajiri, T. Miura, K. Kondo, N. Oshima, T. Hayashi, H. Nakamura, and Y. Ito
The polymerization process of bisphenol-A dicyanate (BADCy) has been studied using a positron-annihilation lifetime technique (PAL). The polymerization was conducted at 150°C, and the process was followed by PAL. Seven kinds of samples with different curing times were also formed at 150°C, and the relation between the period of the curing time and the degree of polymerization was studied. It has been shown that theo-Ps lifetime increases in samples with a higher polymerization than 85%, which is consistent with measurements of the specific volume of BADCy.