Gravimeters

A special laboratory was designed to host gravimeters. Given the delicacy of these instruments and its high sensibility, it is necessary to have control over the thermal behaviour of the building (double chamber with air conditioning system in the external one) and the structural behaviour (isolated concrete pillars; 7 concrete pillars for instruments installation).

Yebes Observatory gravimetry laboratory

Types of gravimeters used in RAEGE:

• FG5 absolute gravimeter. In this gravimeter, a freely falling reflective test mass is dropped in a vacuum chamber which causes optical fringes that can be detected at the output of an interferometer. This signal is used to determine the local gravitational acceleration.

FG5 gravimeter

• A10 gravimeter. It is an absolute gravimeter optimized for fast data acquisition, ease of use, and portability in outdoor applications. The instrument allows true field operation in harsh conditions on open outdoor sites in the sun, snow, and wind.

• OSG relative superconducting gravimeter (SG). In this SG gravimeter, levitation of a spherical test mass in an ultra-stable magnetic field replaces the mechanical springs found in previous relative gravitymeters. Observational data can be used for high precision continuous gravity monitoring for geophysical phenomena such as normal modes, mantle rheology, tides, solid Earth-oceans-atmosphere interactions, hydrology, and Earth rotation.