The Seismic Angular Noise of an Industrial Origin Measured by the Precision Laser Inclinometer in the LHC Location Area

— The decreasing of the relaxation time for recovery of the horizontality of the surface of thin layer of the liquid in the cuvette is a new observed phenomenon caused by the meniscus influence in case of the cuvette small inclination. It was experimentally established that the time of reconstruction of the surface of 4 mm thick liquid layer in the cuvette of ∅5 mm at 0.5 µrad of calibration inclining is 0.082 ± 0.006 s. In this case the relative deviation from the liquid surface planarity does not exceed 7%. The physics explanation of the phenomenon observed is proposed. The taking into account of the time duration of liquid surface horizontality reconstruction in the Precision Laser Inclinometer has resulted in the widening of Inclinometer’s sensitivity range up to 12.3 ± 0.9 Hz. The data obtained could be used when seismoisolating of the research equipment.