High Energy Microbeams and Focusing Limits of Channeling Particles
Presented by Dr. Gennady KOVALEV on 29 Sep 2016 from 18:40 to 19:40
Session: PS3: Poster session
High Energy Microbeams and Focusing Limits of Channeling Particles G.V. Kovalev School of Mathematics, University of Minnesota, Minneapolis, MN 55455,USA The possibility of beam steering of high energy particles by a crystal has been investigated for a long time. Tsyganov was the first who proposed the bent crystal channeling. After the successful demonstration of the bent channeling, it became clear that bent crystals can be used for constructing a focusing element with extremely short focal length and focal spot close to size of one atomic channel. Several crystal devices for focusing were suggested [3-4]. Their common idea is based on differently bent plane channels to provide a 1-D beam convergence to a focal point. Because the crystal planes are naturally parallel, the focusing device must exert an external force making channels converged. Carrigan suggested a simple solution where a monocrystal is partially cut into thin parallel slices with empty gaps between them. To focus the beam the slices should be pressed together. Another solution is to apply a strong external pressure providing channel's convergence of the bulk crystal. The further improvement in this direction are led to mixed crystals with smooth change in the lattice constant. Similar constructions with graded composition layers were suggested and tested for a deflection of particles. All other developments and suggestions are discussed in this work. References  E. N. Tsyganov, Some aspects of the mechanism of a charge particle penetration through a monocrystal, Fermilab,TM-682 (1976) 5.  Y. N. Adishchev, et al, JETP lett. 30 (1979) 402.  R. A. Carrigan, On the possible applications of the steering of charged particles by bent single crystal, Fermilab FN-80/45 (1980) 46.  R. A. Carrigan, The application of channeling in bent crystals to charged particle beams, in: R. A.Carrigan, J. A. Ellison (Eds.), Relativistic Channeling. Plenum, New York, 1987, pp. 339-368.  G. V. Kovalev, Nucl. Instr. and Meth. in Phis. Res. B 207, pp. 428-486.