Some unexpected sporadic increases of an environmental radioactive background have been recorded at mountain level at Baksan Neutrino Observatory (BNO, 1700 m above sea level) using electron-neutron detectors (en-detectors), which could be explained by radioactive aerosol enhancements. The large area inorganic scintillator en-detectors developed for cosmic ray study are continuously monitoring environmental thermal neutron fluxes at various geophysical conditions. Application of the pulse shape discrimination method allows us to select and separately measure both thermal neutrons and radioactive beta-decay nuclides being products of radon decays in air (mostly Rn-222 and Rn-220). There are two en-detector setups running now at BNO, one deep underground while another one at surface. Both installations had recorded some strange sporadic increases of radioactive nuclides in air. In this paper, we present results and the most probable explanation of the significant increases joint by radioactive aerosols production but caused by different reasons: Baksan river floods or nearby underground experiment with powerful Cr-51 radioactive source.

使用电子中子探测器（en-detector）在巴山中微子观测站（BNO，海拔1700 m）的山地上记录到了环境放射性本底的一些意外的零星增加，这可以用放射性气溶胶的增强来解释。为宇宙射线研究而开发的大面积无机闪烁体探测器在不断监测各种地球物理条件下的环境热中子通量。脉冲形状判别方法的应用使我们能够选择并分别测量空气中tron衰变产物（主要是Rn-222和Rn-220）所产生的热中子和放射性β衰变核素。现在，在BNO上运行两种en-detector设置，一种在地下，另一种在地面。两种装置都记录了空气中放射性核素的零星增加。在本文中，我们介绍了放射性气溶胶产生显着增加但由不同原因引起的联合显着增加的结果和最可能的解释：巴克桑河洪水或附近有强力Cr-51放射源的地下实验。