Analysis of the Performance of a Model Quadrupole Magnet for a Linear Accelerator

A model quadrupole magnet for a future linear accelerator has been designed, fabricated, and tested at KEK. The model quadrupole is a superferric superconducting magnet with a design field gradient of 57 T/m. The design field gradient is obtained by saturating the iron yoke. Superferric magnets are considered to have the advantage of simplicity, less sensitivity to the position of the superconductor coils, and are therefore thought to be easier to construct and less expensive than usual superconducting magnets. However, if the iron is heavily saturated, the magnetic field becomes more sensitive to the coil positions. The magnetic properties of the magnet were measured with a harmonic coil, and its field gradient, effective length, and multipole components were compared with a 3D simulation. The results are presented and discussed in this paper.