FIELD: physics.;SUBSTANCE: gravimeter has in a vacuum chamber a ballistic unit with a falling proof mass with a built-in laser interferometer reflector - a device for measuring displacement of the proof mass. The proof mass reflector can be made not only cornered, but also in form of a circular cone with an inner reflecting conical surface with angle of 45° between the generatrix and the axis of the cone. The proof mass is positioned in a top initial position by its top surface, coaxially with the axis of symmetry of a guide rod and a corresponding opening interfaced with it, said opening being located in a fixed flange, and is fixed in the initial position by holding a flexible member on the end of the rod in a fixed position. The ballistic unit also has a trap mounted on the conical section of the free fall trajectory of the proof mass, and a bogie for raising the proof mass to the initial position with a controlled drive.;EFFECT: reliable and accurate fixation of the proof mass in the initial position and reduced angular and spatial deviation of the axis of the proof mass from the vertical during free fall thereof.;2 cl, 3 dwg
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