Preparation and measurement of an ${}^{37}$Ar source for liquid xenon detector calibration

We present the preparation and measurement of the radioactive isotope ${}^{37}\mathrm{A}\mathrm{r}$, which was produced using thermal neutrons from a reactor, as a calibration source for liquid xenon time projection chambers. ${}^{37}\mathrm{A}\mathrm{r}$ is a low-energy calibration source with a half-life of 35.01 days, making it suitable for calibration in the low-energy region of liquid xenon dark-matter experiments. Radioactive isotope ${}^{37}\mathrm{A}\mathrm{r}$ was produced by irradiating ${}^{36}\mathrm{A}\mathrm{r}$ with thermal neutrons. It was subsequently measured in a gaseous xenon time projection chamber (GXe TPC) to validate its radioactivity. Our results demonstrate that ${}^{37}\mathrm{A}\mathrm{r}$ is an effective and viable calibration source that offers precise calibration capabilities in the low-energy domain of xenon-based detectors.