Detection of the naturalαdecay of tungsten

The natural $\alpha$-decay of ${}^{180}\mathrm{W}$ has been unambiguously detected for the first time. The $\alpha$ peak is found in a ($\gamma$, $\beta$, and neutron)-free background spectrum. This has been achieved by the simultaneous measurement of phonon and light signals with the CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) cryogenic detectors. A half-life of $T_{1∕2}=(1.8\pm 0.2)\times {10}^{18}\text{years}$ and an energy release of $Q=[2516.4\pm 1.1\left(\mathrm{stat.}\right)\pm 1.2\left(\mathrm{sys.}\right)]\mathrm{keV}$ have been measured. New limits are also set on the half-lives of the other naturally occurring tungsten isotopes.