• V. Guidi, S. Baricordi, P. Dalpiaz, M. Fiorini
  UNIFE, Ferrara
• A.G. Afonin, Y.A. Chesnokov, V.A. Maisheev, I.A. Yazynin
  IHEP Protvino, Protvino, Moscow Region
• G. Ambrosi, B. Bertucci, W.J. Burger, P. Zuccon
  INFN-PG, Perugia
• D. Bolognini, S. Hasan, A. Mozzanica, M. Prest
  Università dell'Insubria & INFN Milano Bicocca, Como
• G. Cavoto, R. Santacesaria, P. Valente
  INFN-Roma, Roma
• G. Della Mea, R. Milan, A. Vomiero
  INFN/LNL, Legnaro (PD)
• A.S. Denisov, Yu.A. Gavrikov, Yu.M. Ivanov, L.P. Lapina, L.G. Malyarenko, V. Skorobogatov, V.M. Suvorov, S.A. Vavilov
  PNPI, Gatchina, Leningrad District
• A.D. Kovalenko, A.M. Taratin
  JINR, Dubna, Moscow Region
• C. Luci
  Università di Roma I La Sapienza, Roma
• A. Mazzolari
  INFN-Ferrara, Ferrara
• W. Scandale
  CERN, Geneva
• E. Vallazza
  INFN-Trieste, Trieste

The H8RD22 collaboration has accomplished an extensive study of axial channeling in the external lines of the CERN SPS. For 400 GeV protons, it was recorded deflection by about 90% of the particles by a short crystal, by far exceeding the performance of previous experiments. Axial channeling with 150 GeV negative hadrons was also firmly observed with deflection capability comparable to the case of positive particles. Near-axis effect such as multiple-volume reflections in a single crystal as a result of the superposition of volume reflections by a series of parallel planes sharing the same axis was investigated with 400 GeV protons. Confirmation of theoretical expectation was observed, in particular most of the particles were deflected by about 50 urad, four times the deflection angle imparted by a single volume reflection of most efficient planes. In this case the angular acceptance was sensitively broader than for the case of channeling. In summary, channeling in axial mode and multi-volume reflections were proven to be two mechanisms for manipulation steering of high-energy particle beams, which side most established techniques such as planar channeling and volume reflection.*

*Contribution on behalf of the H8RD22 collaboration.

• A. Mazzolari, S. Baricordi, P. Dalpiaz, V. Guidi, G. Martinelli, D. Vincenzi
  UNIFE, Ferrara
• E. Bagli
  INFN-Ferrara, Ferrara

Channeling in bent crystals is a technique with high potential to steer charged-particle beams for several applications in accelerators physics. Channeling and related techniques underwent significant progress in the last years. Distinctive features of performance increase was the availability of novel ideas other than new techniques to manufacture the crystal for channeling. We show the technology to fabricate crystals through non conventional silicon micromachining techniques. Characterization of the realized crystals highlighted that the crystals are free of lattice damage induced by the preparation. The crystals were positively tested at the external line H8 of the SPS with 400 GeV protons for investigation on planar and axial channelings as well as on single and multiple volume reflection experiments by the H8-RD22 collaboration. Selected single- and multi-crystal are candidates for the experiment UA9–an experiment on beam collimation at the CERN SPS.