Project Sherwood is a nation-wide attempt to produce a controlled thermo-nuclear fusion reaction. The Astron experiment, conceived by Nicholas Christofilos, will utilize the effects of a cylindrical layer of relativistic electrons to contain and heat the plasma. A high quality, 200-ampere, 5-Me V electron beam is required to form the electron layer. The electron beam is produced by a linear induction electron accelerator. Three hundred and thirty-three toroidal cores of magnetic material surround an evacuated ceramic accelerating column. The electrons are accelerated by the transverse electric field produced by the changing flux. The magnetic cores are tape-wound toroids of .001", 50% Ni - 50% Fe. Two hundred eighty-eight cores are 24" o.d. x 8-1/2" i. d. x 1/2" thick and the remaining forty-five are 33" o. d. x 18" i. d. x 1/2" thick. Each core is required to support 16 kG for 0.4 psec. The choice of magnetic material was made by testing all available material for the required parameters. Results of these tests are presented.

The work reported here is a continuation of that reported in UCRL-1962. Approximate breakdown voltages and spark damage estimates have been made for the metals Ag, Ti, Aluminum Alloy 52-SO, Stainless Steel 316 and various combinations of Inconel and Cu.