A lab scale experiment for keV sterile neutrino search

We developed a simple small-scale experiment to measure the beta decay spectrum of ${}^3$H. The aim of this research is to investigate the presence of sterile neutrinos in the keV region. Tritium nuclei were embedded in a 1$\times$1$\times$1 cm${}^3$ LiF crystal from the ${}^6$Li(n,$\alpha$)${}^3$H reaction. The energy of the beta electrons absorbed in the LiF crystal was measured with a magnetic microcalorimeter at 40 mK. We report a new method of sample preparation, experiments, and analysis of ${}^3$H beta measurements. The spectrum of a 10-hour measurement agrees well with the expected spectrum of ${}^3$H beta decay. The analysis results indicate that this method can be used to search for keV-scale sterile neutrinos.