Author: Guidi, V.
Paper Title Page
MOPPD082 Recent T980 Crystal Collimation Studies at the Tevatron Exploiting a Pixel Detector System and a Multi-strip Crystal Array 559
  • D.A. Still, G. Annala, R.A. Carrigan, A.I. Drozhdin, T.R. Johnson, N.V. Mokhov, V. Previtali, R.A. Rivera, V.D. Shiltsev, J.R. Zagel, V.V. Zvoda
    Fermilab, Batavia, USA
  • Y.A. Chesnokov, I.A. Yazynin
    IHEP, Moscow Region, Russia
  • V. Guidi, A. Mazzolari
    INFN-Ferrara, Ferrara, Italy
  • Yu.M. Ivanov
    PNPI, Gatchina, Leningrad District, Russia
  • D. Mirarchi, S. Redaelli
    CERN, Geneva, Switzerland
  Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy through the US LHC Accelerator Research Program (LARP).
With the shutdown of the Tevatron, the T-980 crystal collimation experiment at Fermilab has been successfully completed. Results of dedicated beam studies in May 2011 are described in this paper. For these studies, two multi-strip crystals were installed in the vertical goniometer. A two-plane CMS pixel detector was positioned upstream of the E03 collimator to image beam deflected by the crystals. This new enhanced hardware yielded impressive results. For the first time, a 980-GeV proton halo beam, channeled by an O-shaped crystal of the horizontal goniometer, was imaged using the pixel detector. The performance of this crystal, the first element of the collimation system, was very good. Reproducible results on the reduction of local beam losses were also obtained with an 8-strip crystal. For volume reflection these beam losses were measured with the PIN diodes and loss monitors at the E03 collimator. The long range beam losses for the channeled beam were observed using the F17 collimator one third of the ring downstream of the crystal. The measured channeling efficiency of the O-shaped crystal and the volume reflection efficiency of the 8-strip crystal were both ~70%.