Collimation of a Circulating Beam in the U_70 Synchrotron by Use of   Reflections in Axially - Oriented Crystals
  The possibilities of the extraction and collimation of a circulating beam by a new method due to the reflection of particles in crystals with axial orientation were experimentally investigated in the Fall-2010 run at the U_70 synchrotron. Such crystals have positive features, because the axial potential is five times larger than the planar potential. It has been shown that the collimation efficiency can reach 90% due to axial effects in the crystal. Losses of the circulating beam on a collimator have been reduced by several times; this makes it possible to suppress the muon jet near the steel collimator of the circulating beam. 
A. G. Afonin, V. T. Baranov, M. K. Bulgakov, I. S. Voinov, V. N.   Gorlov, I. V. Ivanova, D. M. Krylov, A. N. Lunn'kov, V. A...
physics.acc-ph