Crystal lattice can trap and channel particle beams along major crystallographic directions [1]. In a bent crystal, the channeled particles follow the bend [2]. This makes a basis for an elegant technique of beam steering by means of bent channeling crystals, experimentally demonstrated from 3 MeV [3] to nearly 1 TeV [4]. Protons of 70 GeV were bent up to 150 mrad [5] by a 10-cm Si crystal. Efficiency of 85% [6] was demonstrated in crystal extraction of 10¹² beam of 70 GeV protons. See our publications or read by subject:

Many crystal applications at the Large Hadron Collider are considered, such as beam collimation [1] and extraction [2], crystal bending of the LHC beam for in-situ calibration of ATLAS and CMS calorimeters [3], crystal channeling of LHC forward protons [4] and others.

Crystal collimation was first studied in 1989 at IHEP for 3 TeV UNK [1] and in 1991 for 20 TeV SSC [2] colliders. A proof-of-principle experiment in 1998 at IHEP [3] showed a factor-of-2 reduction in the 70-GeV proton accelerator background with a bent crystal incorporated into beam cleaning system. Crystal collimation for heavy ions was studied at RHIC [4], with efficiency of ~25% [5] (world best for ions). The technique promises a 10-fold reduction in the accelerator-related backgrounds in the Tevatron [6] and LHC [7] colliders. A new technique of multiple volume reflection in bent crystals promises a factor of 100-1000 improvement in beam collimation at LHC [8]. Currently, 1 TeV crystal collimation experiment started at the Tevatron [9]. See also theory development [10].

Volume reflection of beam in a bent crystal was predicted in 1987 [1] and seen first in collimation experiments in colliders [2]. Direct measurement of the effect was reported in 2006 [3] from PNPI (Gatchina) and IHEP (Protvino). In 2007, the effect was confirmed at CERN SPS with 400 GeV protons [4]. Multiple volume reflection [5] can be used to steer particles at significant angles. Efficiency of 99.95% is predicted for crystal reflection of 7 TeV protons at 40 microradian angle [6] suitable for beam collimation in the LHC.

More to follow.

2005 edition: Relativistic Channeling and Coherent Phenomena in Strong Fields workshop, Frascati 25-28 July 2005 Reported in CERN Courier Jan 2006, pages 37-38. Published in NIM B Volume 252, Issue 1, Pages 1-148 (2006)

2004 edition: Relativistic Channeling and Related Coherent Phenomena workshop, Frascati 23-26 March 2004 Reported in CERN Courier July 2004, pages 19-20. Published in NIM B Volume 234, Issues 1-2, Pages 1-167 (2005)

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V.M.Biryukov, Yu.A.Chesnokov, V.I.Kotov. Crystal Channeling and its Application at High Energy Accelerators (Springer, Berlin:1997) 219 pages. Buy it at Amazon or Barnes and Noble. Read (and search!) this book online free at books.google.com

V.M.Biryukov, Yu.A.Chesnokov, V.I.Kotov. Steering of high-energy charged particle beams by bent single crystals. Physics-Uspekhi 37 (1994) pp.937-961. (Introduction into theory and experiment, 25 pp review). Download Russian or English version

Since April 14, 1998