Anodic behaviour of zirconium monocrystals in chloride solutions

The investigation of the alpha decay of odd-odd isotopes of sup(210, 208, 206, 204)At and 212Fr is carried out. The π root 2 alpha-spectrograph has been used. Astatine and francium isotopes have been produced in the deep fission reaction under irradiation of targets from metallic thorium or uranium in the form of plates with the internal proton beam (E=660 MeV) of a synchrocyclotron. Monoisotopic samples of these nuclides have been used. The 110At alpha-spectrum with a monoisotopic sample is investigated for the first time. The obtained data on energy and intensity of eight alpha-transitions turned to be more accurate as compared with the already known. The energies of transitions are refined: 5465.5, 5443.0 and 5387 keV. The alpha-group with Esub(α)=5131 keV has not been detected. The part of the 210At alpha decay is obtained to equal (0.18+-0.002)%. The existence of 208At three alpha transitions detected earlier is confirmed, the values of relative intensities and energies of these transitions are refined. The intensity of 208At possible transitions with the energies of 5.40<E<5.80 MeV does not exceed 0.3% for an alpha decay. The measurement of 206At alpha spectra is performed in the 5.40-6.00 MeV energy range. Besides the previously known alpha group with Esub(α)=5703 keV three new groups with Esub(α)=5774, 5767, 5734 keV have been found. The obtained value of the part of alpha decay (0.70+-0.14)% is somewhat less than the already known. For 204At besides the earlier known alpha group with Esub(α)=(5953+-3)keV other alpha groups with the intensity above 10% of that observed in the energy range of 5.80-6.10 MeV have not been found. The part of the 204At alpha decay is obtained to be equal (3+-1)%. The intensities of 212Fr alpha transitions are refined and particularly alpha lines with the 6262 keV energy. The values of energies and intensities for alpha lines investigated confirm the known data. The results obtained are presented in a form of tables and diagrams