New small diameter rotating coil shaft for characterizing new generation of multipolar magnets

The proliferation of ultimate-light source facilities around the world has yielded the need of accurate characterization of small gap magnets. This also applies to multipolar magnets. Clearance diameters down to 10 mm for quadrupoles and sextupoles become to be used and need to be accurately measured. At these small gaps, the high order multipoles influence on electron beam dynamics is high, and it should be well characterized in order to guarantee a feasible operation of the accelerator. To face this challenge, ALBA magnetic measurement laboratory has developed a new rotating coil shaft with a diameter of 10 mm able to be introduced inside narrow-gap multipolar magnets. In this paper we present the design as well as the manufacturing of such a device.