New devices for the magnetic center location of quadrupole magnets

A system is presently under development at SACLAY for determining the location of the magnetic center of superconducting quadrupole magnets. It uses magnetic crystals in garnet film form, with visualization of the results by an optical method. This paper will describe the sensors, the measuring methods and the results which have been obtained so far, they are quite encouraging for long superconducting quadrupoles, for which the classical mechanical methods have reached their limits