DESIGN AND CONSTRUCTION OF A LARGE-APERTURE QUADRUPOLE ELECTROMAGNET

We are currently constructing a prototype quadrupole electromagnet for the proposed Induction Linac Systems Experiments (ILSE) at LBNL. ILSE (PUB-5219, 1989 (Lawrence Berkeley Laboratory)) will address many phy sics and engineering issues relevant to the design of a heavy ion fusi on driver accelerator. The pulsed electromagnet has two layers of curr ent windings and will produce a field gradient of 28 T m(-1), with a u sable aperture radius of 6 cm. It operates at a repetition rate of 1 H z, steady state. In this paper, we discuss how the interaction of vari ous concerns such as maximum dynamic aperture, short lattice period, f ield quality, iron yoke weight, heat transfer, and voltage stand-off h ave led to our particular design choices. We also present two- and thr ee-dimensional numerical calculations concerning field topography and the results of transport simulations of space-charge-dominated ion bea ms with ILSE parameters.