  Bent crystal situated in a circulating beam can serve for efficient slow
extraction or active collimation of the beams. This technique, well established
at 10-1000 GeV, could be efficient also at the energies as low as 0.1-10 GeV
according to the computer simulations presented in this paper. Applications
might include halo scraping in the Spallation Neutron Source or slow extraction
from synchrotrons.
