3 ms·
> "by looking at the ratio of Cesium 137 and Barium 137, which presumedly someone has done…" That's impractical; the decay product Ba-137 is stable and already
by perihelions 1y ago
> "by looking at the ratio of Cesium 137 and Barium 137, which presumedly someone has done…"
That's impractical; the decay product Ba-137 is stable and already present in much larger amounts, compared against which the Cs-137 decay products are undetectable.