Magnetic Axis and Geometric Measurement for the LHC Cryomagnet

The LHC cryomagnets are made with several types of magnets which all need to be aligned. Both magnetic and geometric axis need to be well known before the installation in the LHC tunnel. These measurements require integrated controls for optical, magnetic and geometric measurements systems. The measurement sequence as well as the analysis should be adapted to each type of magnet. To perform the measurement, a mole, equipped with a reflector, a CCD camera and Hall probe sensors should be moved along the tubes of the 15 metres long dipole magnets and rotated around its axis. The geometrical measurements are made with an industrial Laser Tracker system. Homemade systems have been developed for the image and magnetic measurements. Each part can be driven separately and form the lower layer of the system. The control, as well as the interaction of these systems, has been integrated into a single system using UDP communication. The harmonic analysis allows verification of the quality and the orientation of the magnetic field of the magnet. The geometric measurement program has been designed as a master, thus controlling all sub-systems and the quality of the acquired data. In order to operate the magnetic and geometric measurement independently, a remote control application has been made. The structure of these two major parts, geometric and magnetic, has been designed so that new functionality can easily be added.