Search

Method for production of alpha emitter 149 Tb by irradiation of 151 Eu with 70 MeV 3 He nuclei is proposed. For the first time, the cross sections for the formation of isotopes 149,150,151,152 Tb were measured experimentally using a stack foil technique in the 3 He particles energy range 70 → 12 MeV. The thick target yield of 149 Tb is 39 MBq/μAh, or 230 MBq/μA 149 Tb at saturation. The optimal energy range from the point of view of radioisotopic purity is 70 → 40 MeV. At these conditions about 150 MBq/μA 149 Tb can be produced in 8 hours irradiation, which is sufficient for therapeutic applications. The main impurities are 150 Tb (~100% in activity) and 151 Tb (~30% in activity). The proposed method surpasses its counterparts by the high content of the target isotope in the natural mixture and the simplicity of the radiochemical separation of 149 Tb from the bulk target material.

We study the possibility of increasing the specific activity of 99 Mo produced by irradiating molybdenum targets with the use of the Szilard-Chalmers effect. According to the Szilard-Chalmers effect, recoil atoms of the 99 Mo radionuclide can be produced in nuclear reactions and retained in surrounding buffer substance. The objective of our work is to measure the yield of recoil atoms in the buffer as a function of the molybdenum layer thickness. The yield of recoil 99 Mo atoms in the 100 Mo(p,x) 99 Mo nuclear reaction as a function of metallic molybdenum nanolayer thickness has been measured. Measurements were carried out after irradiation of nanolayers in the U-150 cyclotron with 28-MeV protons. Nanolayers of molybdenum with thickness of 30 to 220 nm were produced by magnetron sputtering on sapphire plates. The yield of the mass of 99 Mo recoil atoms was found to be the highest with the molybdenum layer thickness of 80 ± 5 nm. The enrichment factor (EF) has been defined as a ratio of the 99 Mo collector specific activity (SA) to the entire target SA before separation as EF = 1200 ± 150. The specific activity of 99 Mo produced in the collector was estimated to be approximately equal to 25 Ci·g -1 ., (© 2019 John Wiley & Sons, Ltd.)

This study assessed the effects of combined low-dose neutron and γ-ray irradiation on hippocampal neurogenesis and hippocampal-dependent memory. Neural progenitor cell division and survival were evaluated in brain sections and whole hippocampal preparations following head irradiation at a dose of 0.34 Gy for neutron radiation and 0.36 Gy for γ-ray radiation. Hippocampal-dependent memory formation was tested in a contextual fear conditioning task following irradiation at doses of 0.4 Gy for neutron radiation and 0.42 Gy for γ-ray radiation. Cell division was suppressed consistently along the entire dorsoventral axis of the hippocampus 24 h after the irradiation, but quiescent stem cells remained unaffected. The control and irradiated mice showed no differences in terms of exploratory behavior or anxiety 6 weeks after the irradiation. The ability to form hippocampus-dependent memory was also unaffected. The data may be indicative of a negligible effect of the low-dose of fast neutron irradiation and the neurogenesis suppression on animal behavior at 6 weeks after irradiation.