| Paper |
Title |
Page |
| TUPLS016 |
Characterization of Crystals for Steering of Protons through Channelling in Hadronic Accelerators
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1523 |
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- V. Guidi, S. Baricordi, M. Fiorini, G. Martinelli, A. Mazzolari, E. Milan
UNIFE, Ferrara
- E. Boscolo Marchi, G. Della Mea, R. Milan, S. Todros, A. Vomiero
INFN/LNL, Legnaro, Padova
- A. Carnera, D. De Salvador, A. Sambo
Univ. degli Studi di Padova, Padova
- Y.A. Chesnokov
IHEP Protvino, Protvino, Moscow Region
- Yu.M. Ivanov
PNPI, Gatchina, Leningrad District
- W. Scandale
CERN, Geneva
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Channeling of relativistic particles through a crystal may be useful for many applications in accelerators, and particularly for collimation in hadronic colliders. Efficiency proved to be dependent on the state of the crystal surface and hence on the method used for preparation. We investigated the morphology and structure of the surface of the samples that have been used in accelerators with high efficiency. We found that crystal fabrication by only mechanical methods (dicing, lapping, and others) leads to a superficial damaged layer, which is correlated to performance limitation in accelerators. A planar chemical etching was studied and applied in order to remove the superficial damaged layer. RBS analysis with low-energy protons highlighted better crystal perfection at surface, as a result of the etching. Finally, measurement with 70-GeV protons at IHEP demonstrated a superior performance of the chemically cleaned crystals with respect to conventional samples. A protocol for preparation and characterization of crystal for channelling has been developed, which may be of interest for reliable operation with crystals in accelerators.
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| TUPLS022 |
Experimental Study of Crystal Channeling at CERN-SPS for Beam-halo Cleaning
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1538 |
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- M. Fiorini, P. Dalpiaz, V. Guidi
UNIFE, Ferrara
- G. Ambrosi
INFN-PG, Perugia
- R.W. Assmann, I. Efthymiopoulos, L. Gatignon, W. Scandale
CERN, Geneva
- C. Biino
INFN-Torino, Torino
- Y.A. Chesnokov
IHEP Protvino, Protvino, Moscow Region
- Yu.M. Ivanov
PNPI, Gatchina, Leningrad District
- R. Santacesaria
INFN-Roma, Roma
- A.M. Taratin
JINR, Dubna, Moscow Region
- A. Vomiero
INFN/LNL, Legnaro, Padova
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An efficient and robust collimation system is mandatory for any superconducting hadron collider, in particular for the LHC, which will store a beam of unprecedented high intensity and energy. The usage of highly efficient and short primary bent-crystal collimators might be a possibility for reaching nominal and ultimate LHC intensity. Over the last years, groups in Russia (St. Petersburg) and Italy (Ferrara) have developed crystal production methods, which considerably improve the crystal quality. In view of the crystal-collimation experiments at the Tevatron and of the potential improvement compared with the phas·10-1 LHC collimation system, considering the recent progress in crystal technology, we proposed experiments for crystal characterization in the SPS beam lines. Major objectives will be: 1) qualification of the new crystals to be used in the Tevatron; 2) measuring the channeling efficiency of long crystals with 1 mrad and/or 8 mrad bending angle; and 3) comparison of loss patterns around the ring for a crystal with one for amorphous material. In this paper we will report the progress towards the SPS experiment.
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