Detection of Radon Decay Using the LVD Setup for Searching Neutrinos

The Large Volume Detector (LVD), located in the low-background laboratory of Gran Sasso, Italy, was designed to detect neutrinos from stellar core collapses in our Galaxy. The search for rare events requires careful attention to the experiment’s background, such as the natural radioactivity of rocks and detector materials, as well as the interaction of underground cosmic-ray muons. The LVD setup is capable of detecting gamma quanta from the decay of radon daughter nuclei. We convincingly demonstrate a correlation between the variation in the count rate of background pulses from gamma quanta in the detector and the variation in the concentration of radon nuclei in the experimental hall. We also point out the existence of another source of radon concentration variation — seismic activity.