Patent ID: 8661894

Claim:
An apparatus for micro-gravimetric measurements for geophysical prospecting, whose characteristic is that it comprises: a base frame; a first mass integral to said base frame; a second mass arranged at a distance from said first mass and aligned vertically with respect to said first mass, such that said first and said second mass form a resonator for electromagnetic radiation; means for suspending said second mass, said means for suspending being connected to said base frame and holding resiliently said second mass in order to provide a steady elastic modulus; means for applying an electromagnetic signal to said resonator; means for measuring a resonance frequency of said resonator responsive to said electromagnetic signal, means for correlating the variation of said resonance frequency to a variation of distance between said two masses, and means for correlating the variation of distance to local gravitational acceleration wherein said means for suspending said second mass comprises a torsion pendulum, obtained starting from a cut silicon lamina, said lamina having two opposite C-shaped cuts, in order to separate a fixed portion and a mobile portion, united to each other by two connecting portions urged by torsion by said second suspended mass and said mobile portion; and wherein said two masses consist of sapphire discs located at a predetermined distance.