Abstract :
The microtron (electron cyclotron) originated about the same time, if not earlier, than the synchrotron, but because of limitations as well as assets, its development (reviewed here) has been slow. The potentialities of the microtron in various fields of nuclear and electronic research are discussed. Some of its desirable characteristics are: (a) a fixed magnetic field microwave accelerator capable of considerable reduction in size and weight for the energies attainable (30 mev or higher), (b) field or quasi field-emission electron source with possibility of yields comparable to those of linear accelerators, (c) electron output in small bunches with precise control of timing possible, (d) orbital distribution allowing easy extraction of electron beams for special experiments or for use of microtron as an injector to other accelerators, (e) simplified equipment with easy, stable, and reliable operation, (f) the special form "race-track microtron" has further advantages for experimental work, (g) adaptation to F.F.A.G. magnet structures is a possibility still untouched, (h) modified for use with an auxillary magnetic field rising stepwise in time the "synchro-microtron" may attain high electron energies in very short times. Here the steady field structure may even be dispensed with, giving a compact microwave accelerator.