Decay of ${}^{126}{Sn}$ and of the 19-min and 12.4-day Isomers of ${}^{126}{Sb}$

The

γ

radiations of

\approx 10^{5} - y r

{}^{126}{Sn}

and of the

{}^{126}{Sb}

isomers have been studied with NaI(Tl) scintillation spectrometers and Ge(Li) detectors.

β

-ray spectra were measured with a trans-stilbene scintillation unit, and conversion electrons were examined with Si(Li) detectors. The decay of

{}^{126}{Sn}

involves a 0.25 ± 0.03-MeV

β

transition followed by 21.6-, 23.4-, 42.7-, 64.4-, and 87.7-keV

γ

transitions in

{}^{126}{Sb}

. The 23.4- and 87.7-keV transitions are in prompt coincidence with the

β

rays; the 64.4-keV and either the 21.6- or 42.7-keV transitions deexcite an intermediate delayed level with

t_{\frac{1}{2}} = 0.5 \pm 0.1

μsec. Both the 19-min and the 12.4- day isomers of

{}^{126}{Sb}

have essentially the same 1.90 ± 0.15-MeV maximum

β

-ray endpoint energy; however, the

β

spectrum of the latter is more complex (intense inner groups). The 19-min isomer decays by

β

emission (86%) to excited levels in

{}^{126}{Te}

and by ≤31-keV isomeric transition (14%) to the 12.4-day ground state. The

{}^{126}{Te}

excited levels involved in the decay of both

{}^{126}{Sb}

isomers are at 665(

2^{+}

), 1359(

4^{+}

), 1774(

6^{+}

), 2215, 2395, 2494, 2514, 2702, 2761, 2834, 3086, 3187, and 3413 keV. Spin and parity assignments of

5^{+}

and

8^{-}

are proposed for the 19-min and 12.4-day isomers, respectively. The total

β

-disintegration energy of the

{}^{126}{Sb}

ground state is 3.67 ± 0.15 MeV.

This publication has 19 references indexed in Scilit:

Decay ofSn126and of the 19-min and 12.4-day Isomers ofSb126