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 physics and engineering issues relevant to the design of a heavy ion fusion driver accelerator. The pulsed electromagnet has two layers of current windings and will produce a field gradient of 28 T m−1, with a usable aperture radius of 6 cm. It operates at a repetition rate of I Hz, steady state. In this paper, we discuss how the interaction of various concerns such as maximum dynamic aperture, short lattice period, field quality, iron yoke weight, heat transfer, and voltage stand-off have led to our particular design choices. We also present two- and three-dimensional numerical calculations concerning field topography and the results of transport simulations of space-charge-dominated ion beams with ILSE parameters.