Speaker
Description
Potassium-40 ($^{40}$K) is a naturally-occurring, radioactive isotope of interest to rare-event searches as a challenging background. In particular, NaI scintillators contain $^{40}$K contamination which produces an irreducible $\sim 3\text{ keV}$ signal originating from this isotope's electron capture (EC) decays. In geochronology, the $\mathcal{O}(\text{Gy})$ lifetime of $^{40}$K is utilized in dating techniques. The direct-to-ground-state EC intensity ($I_\text{EC}$) of this radionuclide has never been measured, and theoretical predictions are highly variable ($I_\text{EC} \sim (0.05(1)–0.22(4))\%$). The poorly understood intensity of this branch may affect the interpretation or precision of experimental results, including those probing DM signals in the (2-6) keV region. The KDK ("potassium decay") experiment is finalizing the first measurement of this $I_\text{EC}$ branch, which uses a coincidence technique between a high-resolution $\mathcal{O}(\text{keV})$ Silicon Drift Detector and a highly-efficient ($\sim 98\%$) $\mathcal{O}(\text{MeV})$ Modular Total Absorption Spectrometer (Oak Ridge National Labs) to differentiate ground and excited state EC decays of $^{40}$K. We report on the status of the main $^{40}$K analysis leading up to unblinding, along with a preliminary measurement of Zinc-65 decays used to test analysis methods.
| email address | 16lmh@queensu.ca |
|---|---|
| Please select: Experiment or Theory | Experiment |
