Second slow extraction of relativistic nuclear beams from the Synchrophasotron

The second system of slow extraction of light nuclear beams with an energy from 200 MeV/n to 3 GeV/n has been under operation at the Synchrophasotron (SPT) since 1988. To decrease the dimensions of a strongly divergent beam passing through the fringing field, gradient shims have been installed. This makes it possible to extract and to transport about 30% of a circulating beam. Such a limitation of the extraction coefficient is determined by a one-stage deflecting system consisting of a septum magnet and a quadrupole septum lens. The existing equipment of the straight sections does not allow the second stage of the inner transport line to be installed. During one cycle the operation of the second extraction with the first one (the extraction coefficient is about 90% and the energy 4 GeV/n) increases significantly the efficiency of operation of the SPT for nuclear research.<
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