[en] Concentration limits of ¹¹C, ¹³N and ¹⁵O in drain water were estimated for radiation safety design of high-energy accelerators. These short-lived radionuclides are produced in cooling water of high-energy accelerators through nuclear reactions. The estimated limits were 1 x 10¹ Bq/cm³ for ¹¹C, 2 x 10¹ Bq/cm³ for ¹³N and 8 x 10¹ Bq/cm³ for ¹⁵O. (author)

[en] The cross-sections for the reactions ¹²C(antip,antip')¹²C^* (2⁺, 4.44 Mev; o⁺, 7.65 Mev; 3^-, 9.64 Mev) are calculated in terms of the antiproton-nucleon scattering amplitude, the elastic-scattering amplitude of antiprotons on mass-11 nuclei and the inelastic-transition densities obtained by analysing inelastic electron scattering data. The results reproduce the available data at 180 and 46.8 MeV. The relation of the cross-sections for the inelastic- to the elastic-scattering amplitude is discussed. The cross-sections for inelastic scattering even at small angles serve to rule out such an optical potential that gives rise to the backward peak in the cross-sections for elastic scattering

[en] Air has been irradiated with high energy protons at the 12 GeV proton synchrotron to obtain the following parameters essential for the internal dose evaluation from airborne ¹¹C produced through nuclear spallation reactions: the abundance of gaseous and particulate ¹¹C, chemical forms, and particle size distribution. It was found that more than 98% of ¹¹C is present as gas and the rest is aerosol. The gaseous components were only ¹¹CO and ¹¹CO₂, and their proportions were approximately 80% and 20%, respectively. The particulate ¹¹C was found to be sulphate and/or nitrate aerosols having a log-normal size distribution; the measurement using a diffusion battery showed a geometric mean radius of 0.035 μm and a geometric standard deviation of 1.8 at a beam intensity of 6.8x1¹¹ proton.pulse^-1 and an irradiation time of 9.6 min. By taking the chemical composition and particle size into account, effective doses both from internal and from external exposures per unit concentration of ¹¹C were calculated for various room sizes. The values can be used to evaluate the effective dose from the airborne ¹¹C produced in the accelerator tunnels. (author)

[en] The break-up reactions of light nuclei (⁴He, ³He and ³H) induced by anti p give information on anti pn amplitudes. The neutron knock-out process is sensitive to anti pn amplitudes. The comparison between the neutron and proton knock-out processes gives a useful tool to get information on anti pn amplitudes. (orig.)

[en] The recoil behaviour of central metal atoms has been investigated in copper and zinc phthalocyanine mixed crystal systems in thermal neutron irradiation or bremsstrahlung irradiation. The retentions of copper nuclides showed similar tendencies for both irradiations, decreasing with increasing mole fraction of zinc phthalocyanine, while the retentions of zinc nuclides showed various features depending on the kind of irradiation, the radionuclide concerned and the temperature. (author)

[en] The retentions of cobalt, copper and zinc recoils were studied in the mixed crystal system of α-cobalt phthalocyanine and α-zinc phthalocyanine. The hot atoms studied were produced through photonuclear or (n,γ) reactions. 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. (author) 14 refs.; 4 figs

[en] In this paper the cross sections for the nucleon knock-out reactions on light nuclei induced with antiprotons are calculated in the framework of the Glauber approach. It is investigated how bar pN amplitudes are reflected in the cross sections. The reactions are useful to extract information of the bar pn scattering amplitude, since the cross sections are sensitive to the bar pN scattering amplitudes

[en] Since the revised Japanese Radiation Protection Law requires that the dose equivalent of neutron be evaluated with double the quality factor, it becomes necessary to review the neutron dose equivalent with the new quality factor. At high energy proton accelerators, stray neutrons are produced mostly at target stations for secondary beam lines and beam dumps. Stray neutrons are also produced by a beam loss along the beam lines. The stray neutrons after penetrating through shields have widely varying energies from thermal to nearly the accelerated proton energies. Here, the Bonner sphere spectrometer and activation detectors are used to obtain neutron energy spectra outside the shield of the EP2 proton beamline in the counter wall at the National Laboratory of High Energy Physics. Results agree well with the calculation by O'Brien and a dose equivalent deduced from the spectrum is also comparable with the regular field monitoring at the Laboratory using a dose equivalent rem counter. In the measurements made, higher energy neutrons than 20MeV are observed and contribute 50 % to the dose equivalent. As a result, it seems reasonable that, in the regular field monitoring with a rem counter, readings of the counter are doubled in evaluating the radiation level in μSv/h. (N.K.)

[en] Uranium in Japanese tobacco leaves and human hair was determined by the fission track method. It was found that the uranium content in smokers' hair was higher than in non-smokers'. Furthermore, a part of uranium was lost from tobacco leaves by ashing at 500-700 deg C. These two results suggest that uranium would be inhaled through smoking. (author) 12 refs.; 2 tabs

[en] The chemical effect of ⁷Be recoils formed through a ¹²C (γ,nα)⁷Be process from ligand carbon atoms was investigated in several phthalocyanines. It was found that ⁷Be-phthalocyanine was synthetized by ⁷Be recoil. Net radiochemical yields of ⁷Be-phthalocyanine were estimated to be 10-20% for copper and zinc phthalocyanines, while for metal-free phthalocyanines more than 90% were obtained. (author)