Magnet and cryostat configurations for a multi-port quadrupole array

This report describes the results of a study of arrays of up to sixteen quadrupoles in a single cryostat surrounded by an induction accelerator that is used for accelerating high current heavy ion beams for fusion. Each quadrupole in the array can have a gradient of 72 T/m, when the quadrupole has a warm bore diameter of 90 mm. An array of sixteen quadrupoles can be made to fit into a round cryostat vacuum vessel with a diameter of 850 mm. If the number of quadrupoles in the array is reduced to nine, the outer diameter of the cryostat is 700 mm. It is proposed that the quadrupole array be conduction cooled using either a 4 K cryocooler or two phase liquid helium in pipes around the magnet array. The two-phase helium can be supplied to a string of multi-bore quadrupoles using a large refrigerator.