Crystal lattice can trap and channel particle beams along major crystallographic directions
In a bent crystal, the channeled particles follow the bend
This makes a basis for an elegant technique of beam steering
by means of bent channeling crystals, experimentally demonstrated from 3 MeV
 to nearly 1 TeV
Protons of 70 GeV were bent up to 150 mrad
 by a 10-cm Si crystal.
Efficiency of 85%  was demonstrated
in crystal extraction of 1012 beam of 70 GeV protons.
or read by subject:
Many crystal applications at the Large Hadron Collider are considered,
such as beam collimation
crystal bending of the LHC beam for in-situ calibration of ATLAS and CMS calorimeters
crystal channeling of LHC forward protons
Crystal collimation was first studied in 1989 at IHEP for 3 TeV UNK
and in 1991 for 20 TeV SSC
A proof-of-principle experiment in 1998 at IHEP
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 ,
with efficiency of ~25%  (world best for ions).
The technique promises a 10-fold reduction in the accelerator-related backgrounds in the
and LHC  colliders.
A new technique of multiple volume reflection in bent crystals promises a factor of 100-1000
improvement in beam collimation at LHC .
Currently, 1 TeV crystal collimation experiment started at the Tevatron
See also theory development
Volume reflection of beam in a bent crystal was predicted in 1987
and seen first in collimation experiments in colliders
Direct measurement of the effect was reported in 2006
PNPI (Gatchina) and IHEP (Protvino).
In 2007, the effect was confirmed at CERN SPS with 400 GeV protons
Multiple volume reflection
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  suitable for beam collimation
in the LHC.