Large Hadron Collider (LHC) at CERN, the European Organization for Nuclear Research, has, on each side of its four experiments, a set of three magnets, called low-beta magnets. These magnets provide the final-focus for the beams that collide head on in the experiments. The magnets have to be permanently monitored with micron precision as they are crucial for collisions with high luminosity in the experiments. The systems used are hydrostatic levelling systems, wire position systems and invarradial systems. The sensors have to withstand a highly radioactive environment,strong magnetic fields and cannot be returned for check and calibration to the manufacturer once exposed to radiation. In order to validate the sensors before their installation in the tunnel, to check them within their measurement system and for check and calibration after use, a series of tests have been put in place
