Development of liquid scintillators loaded with alkaline earth molybdate nanoparticles for detection of neutrinoless double-beta decay

To determine whether neutrinoless double-beta decay occurs is an enormous challenge in particle physics. For this purpose, developing a highly transparent liquid scintillator that contains a candidate isotope at high concentration is required. In this work, ¹⁰⁰ Mo was selected as the isotope and surface-modified nanoparticles were applied. AMoO ₄ alkaline earth molybdates (A = Ca, Sr, and Ba) were synthesized with a subcritical hydrothermal method so that they were well dispersed in organic solvents. The crystalline phase of the nanoparticles was confirmed with X-ray diffraction measurements. The particle size of SrMoO ₄ nanoparticles was found to be the smallest from a transmission electron microscope examination. The SrMoO ₄ nanoparticles were incorporated in liquid scintillators, resulting in high transparency and efficient scintillation. In conclusion, liquid scintillators loaded with organic modified SrMoO ₄ nanoparticles were successfully developed.