• N.V. Mokhov, G. Annala, A. Apyan, R.A. Carrigan, A.I. Drozhdin, T.R. Johnson, A.M. Legan, R.E. Reilly, V.D. Shiltsev, D.A. Still, R. Tesarek, J.R. Zagel
  Fermilab, Batavia
• R.W. Assmann, V.P. Previtali, S. Redaelli, W. Scandale
  CERN, Geneva
• Y.A. Chesnokov, I.A. Yazynin
  IHEP Protvino, Protvino, Moscow Region
• V. Guidi
  INFN-Ferrara, Ferrara
• Yu.M. Ivanov
  PNPI, Gatchina, Leningrad District
• S. Peggs
  BNL, Upton, Long Island, New York
• M. Prest
  Università dell'Insubria & INFN Milano Bicocca, Como
• S. Shiraishi
  Enrico Fermi Institute, University of Chicago, Chicago, Illinois

Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.

Bent-crystal channeling is a technique with a potential to increase the beam-halo collimation efficiency at high-energy colliders. First measurements at the Tevatron in 2005 have shown that using a 5-mm silicon crystal to deflect the proton beam halo onto a secondary collimator improves the system performance by reducing the machine impedance, beam losses in the collider detectors and irradiation of the superconducting magnets, all in agreement with simulations. Recent results, obtained with substantially improved goniometer and enhanced beam diagnostics, are reported showing channeling collimation of the ~1-TeV circulating proton beam halo at the Tevatron collider. Comprehensive results of computer modeling are presented which allow further developments of the T-980 experiment towards a robust system compatible with requirements to high-efficient collimation at the Tevatron and LHC hadron colliders.

Slides

• 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.