Progress in study of efficient crystal extraction and collimation at IHEP

The radical efficiency increase of accelerator beam extraction by means of bent crystals is reached by reducing the longitudinal dimension and bending angle of crystals. The usage of short crystals results in reduction of dechanneling losses and in increase of average number of crystal crossings by particle. Both factors allowed to get a 70 GeV beam extraction efficiency more than 80% which was experimentally proved and is in a good agreement with theory predictions. The feasibility of efficient work of crystal at injection energy (1.3 GeV) is demonstrated as well.