These spallation neutrons convert fertile thorium to protactinium-233 and after 27 days into fissile uranium-233 and drive the fission reaction in the uranium.
Uniquely, EMMA is a new hybrid of a cyclotron and a synchrotron, combining their advantages into a compact, economical form.
In a conventional synchrotron such a variation results in beam loss as the tune hits various resonance conditions.
[4] Richard Garwin and Georges Charpak describe the energy amplifier in detail in their book "Megawatts and Megatons: A Turning Point in the Nuclear Age?"
Earlier, the general concept of the energy amplifier, namely an accelerator-driven subcritical reactor, was covered in "The Second Nuclear Era" (1985), a book by Alvin M. Weinberg and others.