Radioactive Haloes. Possible Identification of ‘Hibernium’

Abstract

SOME years ago, Prof. Joly (Proc. Roy. Soc., A, 102, 682; 1923) discovered radioactive haloes which could not be ascribed to any known radioactive product. One class, not unlike thorium haloes, he called X-haloes; asecond class, of radii less than those of other haloes, he called ‘hibernium’ haloes, hibernium being the suggested name for the new radioelement causing the halo. Recently, S. Iimori and J. Yoshimura(Sci. Papers Inst. Phys. Ghem. Res. Tokyo, 5, 11; 1926) have found a class of haloes not unlike X-haloes which they call Z-haloes. They suggest that the X-haloes and possibly the haloes ascribed by Prof. Joly to radon are identical with these, and that they are due to products of the actinium series. Z-Haloes have some times two inner rings smaller in radius than any caused by a known radioactive product, and these they ascribe to two uranium isotopes at the head of the actinium series with half-value periods of the orders of 10¹² and 10²³ years. They also state that their work on Z-haloes definitely establishes that the actinium series originates independently of the uranium series.