Solar neutrino observation based on fluoride scintillation crystals

A number of experiment groups has measured the neutrino flux from the Sun, that is, the electron neutrino survival probability, so far. Especially, the matter effect on the oscillation (Mikheyev–Smirnov–Wolfenstein effect) was predicted that the survival probability of electron neutrinos tends to decrease at the neutrino energy of a few MeV. However, to fix the effect, it is necessary to improve the measurement accuracy of the electron neutrino survival probability and energy resolution. We propose a new detector concept based on the fluoride inorganic scintillation crystals. A reason for using crystals is that their light yield is larger than that of Cherenkov radiators and liquid organic scintillators, and it is expected to result in high-resolution energy determination. Further, the fluorine-19 captures electron neutrinos ($>3~{\rm MeV}$), then produces a $^{19}$Ne and an electron, where the capture cross section is higher than the scattering. The Neon-19 decays with a half-life of approximately 17 seconds and emits a positron, which then annihilates. Two gamma rays are subsequently emitted. Using pixelated crystals, the coincidence techniques for the four particles, and kinematical event selection, the electron-neutrino events can be identified with strong evidence. In this study, we simulated the feasibility of solar neutrino observations with fluoride scintillation crystals.