The Radioactive Decay ofCs134,Os185,

J. M. Cork

¹

,

James LeBlanc

²

,

W.H. Nester

³

et al.

Abstract

From sources of cesium of high specific activity produced in the pile and studied in photographic magnetic spectrometers, nineteen electron conversion lines are observed. These are interpreted to show the existence of eleven gamma-rays, four of which have not been previously reported. Certain K/L ratios are measured and the resolution of the components of the beta-radiation presented. A plausible decay scheme consisting of seven levels in the resultant barium 134 nucleus is offered.By irradiating osmium sources for various periods in the pile and obtaining successive exposures in magnetic spectrometers, it is possible to determine the energy and half-life of each electron conversion-line. Osmium 185 decays by K capture with a half-life of 96 days. Four gamma-rays are associated with this activity. Osmium 191 decays by a 14-hour isomeric transition followed by beta-emission With 15-day half-life. Two gamma-transitions in sequence follow the beta-decay. Osmium 193 is a beta-emitter with a 31-hour half-life. Some eighteen electron conversion lines are observed which indicate the presence of nine gamma-rays, only three of which had been previously observed.

THE DECAY OF Os191 AND Os193

“…of Cork et al (1953). The errors in energy quoted represent standard deviations in the mean of a t least seven independent determinations except in the case of a few of the weaker lines where only two or three were made.…”

“…The decay of OsIg3 has been studied by Bunlter et al (1950), Swan and Hill (1952), Cork et al (1953), and de Waard (1954. In particular de Waard has firmly established four levels in Oslg3 by means of an electron coincidence spectrometer.…”

The level scheme of 134Ba

“…(b) First-order diffraction profile of the 327 keV gamma ray. The solid lines merely indicate the trend of the data points.Transitions in the 200 keV region have been reported previously 2,6,7,14, is,17,21). A search of the region between 195 keV and 205 keV was made with the curvedcrystal spectrometer.…”

Estudo do decaimento β- do 193Os

“…O engano durou mais de uma década, com diversos estudos sendo publicados com as meias-vidas trocadas [13][14][15][16] . Só em 1952, em um experimento com fótons de 22MeV, Swan e Hill [17] identificam corretamente a meia-vida de 30h com o decaimento do 193 Os para o 193 Ir; neste mesmo artigo já são identificadas nove transições γ do 193 Ir, e nos anos seguintes Cork et al [18] e Waard [19] já esboçam os primeiros esquemas de níveis para este núcleo, ainda que com poucas transições e diversos erros de posicionamento.…”