We report on a search for coherent elastic neutrino-nucleus scattering ($\mathrm{CE}\nu \mathrm{NS}$) using cryogenic sapphire (${\text{Al}}_2{\mathrm{O}}_3$) detectors deployed at the Mitchell Institute Neutrino Experiment at Reactor (MINER), located near the $1{\mathrm{MW}}_{\mathrm{th}}$ TRIGA research reactor at Texas A&M University. The experiment operated with a primary detector mass of 72 g and achieved a baseline energy resolution of $\sim 40\mathrm{eV}$. Using exposures of $158\mathrm{g}\text{−}\mathrm{days}$ (reactor-ON) and $381\mathrm{g}\text{−}\mathrm{days}$ (reactor-OFF), we performed a statistical background subtraction in the energy region of 0.25–3 keV. A geant4 simulation has been performed to understand the reactor-correlated background present in the data, and it agrees with our observations. After accounting for this background, the profile-${\chi }^2$ analysis yields no statistically significant $\mathrm{CE}\nu \mathrm{NS}$ excess. The best-fit signal strength is consistent with the physical boundary ($\rho =0$), and we set a 90% confidence level upper limit of $\rho <2213$ on the $\mathrm{CE}\nu \mathrm{NS}$ rate relative to the Standard Model prediction. This result indicates that the current analysis is dominated by residual low-energy backgrounds. To have enhanced sensitivity, the MINER Collaboration plans to relocate the experiment to the $85{\mathrm{MW}}_{\mathrm{th}}$ High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). With improved shielding, increased detector mass, and higher antineutrino flux, the upgraded setup is projected to achieve a $3\sigma$ $\mathrm{CE}\nu \mathrm{NS}$ detection within $30\mathrm{kg}\text{−}\mathrm{days}$ of exposure.

Close

PrevNext

View figure in article

• Elastic scattering reactions
• Neutrino interactions
• Nucleus-neutrino interactions
• Particle detection signatures
• Particle interactions
• Cryogenics
• Neutrino detection