DESIGN AND STATUS OF THE 1.5 GeV-HARMONIC DOUBLE SIDED MICROTRON FOR MAMI

A Harmonic Double Sided Microtron (HDSM) is pres- ently under construction to increase the end energy of the three staged cw Race-Track Microtron (RTM) cascade MAMI from 0.855 to 1.5GeV. This new accelerator, scheduled to come into operation in 2004, consists mainly of two pairs of 90° bending magnets and two linear accel- erators (see Fig. 1). Special features of the HDSM are the operation of the two linacs at different frequencies, 2.45GHz and 4.90GHz, for higher longitudinal stability, and a relatively strong field gradient in the bending mag- nets for the compensation of vertical edge defocu sing. In this paper we will present the main design consid- erations and report the status of construction.