Array of purcell filters for improving field quality and reducing iron weight in wide aperture superferric magnets

Purcell filters are used for improving the field quality in dipoles and other magnets. These filters are voids in iron poles, which modify the field and improve the field quality of the magnets, especially in wide aperture magnets. Generally, one or two Purcell filters are used in a pole. In this work we have employed a periodic array of Purcell filters in a dipole magnet to reduce the field harmonics and improve the field uniformity. The technique has been applied to improve the design of a 9.750 sector dipole needed in the Super Fragment Separator (Super-FRS) of the upcoming FAIR project. A large reduction in the magnet size and weight has been obtained by using the array. A weight of 50 ton obtained in the original design has come down to 32 ton by the present method.