Die magnetischen Momente der 5⁻-Niveaus von Sn¹¹⁸ und Sn¹²⁰

Abstract

The rotations ofγγ-angular correlations in strong external magnetic fields were observed in the decay of 5.1h Sb¹¹⁸ and 5.8d Sb¹²⁰. Values of the gyromagnetic ratios of the 5⁻ two particle states of Sn¹¹⁸ and Sn¹²⁰ were derived.

In the case of 5.1 hours Sb¹¹⁸ the rotation of the 254 keV-1.221 MeVγγ-angular correlation in a field of 40950 Gauss was measured as

$$\omega _L \cdot \tau = 0 \cdot 417 \pm 0 \cdot 038,$$

, and theg-factor of the 5⁻ state was derived as

$$g = - 0 \cdot 068 \pm 0 \cdot 007.$$

.

This value is correct under the assumption that the rotation in the 4⁺ state is negligible. The half life of this state was found to be

$$T_{\tfrac{1}{2}} \underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{ \leqslant } 7 \cdot 10^{ - 10} \sec .$$

In the case of 5.8d Sb¹²⁰ the rotation of the 200 keV-90 keVγγ-angular correlation in a field of 53200 Gauss was found to be

$$\omega _L \cdot \tau = 0 \cdot 150 \pm 0 \cdot 020,$$

and theg-factor of the 5⁻ state was derived as

$$g = - 0 \cdot 074 \pm 0 \cdot 010.$$

The evaluation implies a small correction for the Compton-underground of the high energyγ-transitions. It is assumed that the rotation in the 4⁺ state is negligible. The half life of the 4⁺ state was found to be

$$T_{\tfrac{1}{2}} \underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle-}$}}{ \leqslant } 6 \cdot 10^{ - 10} \sec .$$

The half lives of the 5⁻ states of Sn¹¹⁸ and Sn¹²⁰ were determined as

$$T_{\tfrac{1}{2}} = \left( {21 \cdot 7 \pm 0 \cdot 2} \right) \cdot 10^{ - 9} \sec $$

and

$$T_{\tfrac{1}{2}} = \left( {5 \cdot 53 \pm 0 \cdot 06} \right) \cdot 10^{ - 9} \sec $$

respectively.

Differential angular correlation measurements proved that attenuations in the 5⁻ states by internal fields were very small for the liquid sources used in these experiments.

The results for the gyromagnetic ratios of the 5⁻ states are consistent with the theoretical interpretation of these levels as mainly (h 11/2,s 1/2) two-neutron-configurations.