From MAMI to the polytrons - microtrons in the 10 GeV range

Acceleration of electrons allows multiple use of a linac by recirculation. For cw operation it is even required for economic reasons, whether the linac is normal conducting or superconducting. Some supplementary remarks are given on the construction of the cw microtron cascade Mainz Microtron or MAMI. Certain aspects of higher order microtrons as accelerators for up to about 30 GeV are presented (Bicyclotron, Hexatron, Oktotron). Non-isochronous recirculation generally results in a most beneficial output energy stabilisation. The special microtron philosophy allows an elegant method of longitudinal tune control. (R.P.) 19 refs.; 7 figs.; 1 tab