Speaker
Description
Potassium-40 ($^{40}$K) is a radioactive isotope of potassium that is found in rocks and the human body. It has two daughter isotopes, argon-40 ($^{40}$Ar), and calcium-40 ($^{40}$Ca). The most common decay of $^{40}$K is to $^{40}$Ca via $\beta$- decay, with a branching ratio of approximately 89.25%. The decay to $^{40}$Ar can occur through three methods, electron capture to an excited state of $^{40}$Ar, electron capture to the ground state of $^{40}$Ar, and $\beta$+ decay. The electron capture decay to an excited state of $^{40}$Ar is the most common of the three with a branching ratio of 10.55%. The decay via electron capture to the ground state of $^{40}$Ar was first measured by the potassium decay~(KDK) experiment, and found a branching ratio of approximately 0.1%. The final decay channel is through $\beta$+ decay. This is the rarest decay with a branching ratio of approximately 10$^{-5}$%. This decay was studied previously in the 1960s, however the experimental branching ratio does not agree with modern theoretical predictions. The KDK+ experiment is seeking to accurately measure this branching ratio by using a potassium salt dissolved in a liquid scintillator, and surrounded by 4 external $\gamma$ detectors. $\beta$+ signals are detected using a triple coincidence between the liquid scintillator, for the $\beta$+ interactions, then two back-to-back 511 keV detections in opposing $\gamma$ detectors. This talk presents an overview of the experiment, as well as the work that has been done to characterize the liquid scintillator.
| Keyword-1 | Potassium-40 |
|---|---|
| Keyword-2 | positron |
| Keyword-3 | Liquid Scintillator |
