Energy Levels inPo210

Abstract

The $K$-capture decay of ${\mathrm{At}}^{210}$ to levels in ${\mathrm{Po}}^{210}$ has been investigated in detail using conversion electron and $\gamma$-ray spectroscopy, and coincidence techniques. Ten transitions of the following energies and indicated multipolarities have been observed: 0.047 ($E2\mathrm{}$), 0.116 ($M1\mathrm{}$), 0.246 ($E2\mathrm{}$), 0.404, 1.185 ($E2\mathrm{}$), 1.441 ($E1\mathrm{}$), 1.487 ($E1\mathrm{}$), 1.604 ($E1\mathrm{}$), 2.23, and 2.6 Mev. On the basis of these measurements, a consistent decay scheme may be proposed. Tentative $\gamma -\gamma$ angular correlation measurements confirm this scheme. The spin and parity of ${\mathrm{At}}^{210}$ are probably 4-, 5-, or 6±. Some information has also been obtained on other At isotopes. A weak 671-kev $\gamma$ ray not in coincidence (within 0.1 μsec) with $K$ x-rays or $\alpha$ particles appeared in the decay of ${\mathrm{At}}^{211}$. Gamma-ray transitions of 83.8, 91.1, 195, 548, and 784 kev were observed in the decay of ${\mathrm{At}}^{209}$.