Das gyromagnetische Verh�ltnis des 2+-Rotationsniveaus von Hf178 und weitere Untersuchungen zum Zerfall von W178

Abstract

The nuclearg-factor of the 2+ rotational state of Hf178 was determined by a measurement of the rotation of the angular correlation between the gamma-group of ∼1350 keV and the 93 keV radiation in an external magnetic field of 49550 gauss. The result is: $$g_R = + 0 \cdot 356 \pm 0 \cdot 035.$$ Liquid sources of 21 days W178 (ammoniumtungstate in aqueous solution) in equilibrium with 9.3 min Ta178 have been used for these measurements. Differential angular correlation measurements showed the existence of a strong time dependent attenuation. The observed attenuation parameters are: $$\begin{gathered} \lambda _2 /\lambda = 0 \cdot 85 \pm 0 \cdot 23 \hfill \\ \lambda _4 /\lambda = 0 \cdot 74 \pm 0 \cdot 10. \hfill \\ \end{gathered} $$ The true coefficients of the angular correlation between the gamma-group of ∼1350 keV and the 93 keV radiation were derived as: $$\begin{gathered} A_2 = + 0 \cdot 330 \pm 0 \cdot 047 \hfill \\ A_4 = 0 \cdot 990 \pm 0 \cdot 060. \hfill \\ \end{gathered} $$ As they are substantially larger than previously published values a reinterpretation of the correlation function is given. The half-life of the 93 keV state was found to be: $$T_{\tfrac{1}{2}} = (1 \cdot 49 \pm 0 \cdot 05) \cdot 10^{ - 9} \sec $$ in good agreement with the coulomb excitation data.