Beam extraction system of the Synchrophasotron

The creation of a beam extraction system of the Synchrophasotron (SPT) began in the seventies. The high efficiency of the extraction system met the usual requirements - receiving an intense beam and lowering the induced radiation of accelerator parts. But besides that the authors had to have high efficiency because the radiation around the SPT had to reduced as there is no biological shield and experiments with internal beam was limited to 1011ppp. The alternative of an intricate and high cost radiation shield was to extract the beam with an efficiency of more than 90% and to transport it into the external experimental halls with suitable beam stoppers, which allowed the accelerator beam intensity to be increased at least by a factor of ten. The design and operation of this extraction system is described