Optical Isomer Shift for the Spontaneous-Fission IsomerAmm240

Autor: J. P. Young, C. E. Bemis, J. R. Beene, S. D. Kramer
Rok vydání: 1979
Předmět:
Zdroj: Physical Review Letters. 43:1854-1858
ISSN: 0031-9007
DOI: 10.1103/physrevlett.43.1854
Popis: The optical isomer shift in the $^{8}S_{\frac{7}{2}}\ensuremath{\rightarrow}^{10}P_{\frac{7}{2}}$ atomic transition in neutral americium has been measured for the \ensuremath{\sim}1-ms spontaneously fissioning isomer, $^{240}\mathrm{Am}^{m}(\mathrm{S}\mathrm{F})$. With use of a laser-excited optical pumping technique, this transition is shifted by +2.6 \ifmmode\pm\else\textpm\fi{} 0.2 \AA{} to 6407.2\ifmmode\pm\else\textpm\fi{}0.2 \AA{} implying a difference in nuclear mean square radii, $\ensuremath{\delta}〈{r}^{2}〉$, of 5.1\ifmmode\pm\else\textpm\fi{}0.2 ${\mathrm{fm}}^{2}$ between the fission isomer and the normal ground state. These experiments provide the first direct experimental proof for the large deformations expected for fission isomers.
Databáze: OpenAIRE