Development of permanent magnet quadrupole for particles accelerator

Storage ring light sources are in constant improvement in order to increase the intensity and the coherence of the X-rays beams. These improvements require stronger multipoles magnet in the accelerator lattice. To reach such strength, the magnets apertures are significantly reduced. The reduction of magnet apertures makes the permanent magnet technology very attractive for some magnets provided that they are limited field tuning. Indeed, introduction of PMs structures may lead to better performances for a more compact design. Furthermore, with this technology running cost can be very low. A simple PM based high gradient quadrupole prototype has been built and magnetically characterized. This magnetic structure results from a compromise between performance and technological complexity. It includes simple soft iron parts and PMS blocks. A suitable field quality was obtained with an optimized pole shape. Mechanicals errors during assembly are corrected with shims to reach the required field quality. (author)