BEAM HALO CRYSTAL EXTRACTION FROM THE TEVATRON DURING COLLIDER RUNS

We have shown by the computer simulation how to extract 1-TeV beam hal o protons from the Tevatron using a bent crystal. More than 10(7) prot ons per second, now lost on scrapers and collimators, can be extracted in a ''passive'' mode, without interference with colliding beam exper iments. This would reduce background in the colliding beam detectors. The problem of an existing imperfect layer at a bent crystal surface i s solved by means of a thin crystal that is used as a crystal mirror f or beam halo particles. The extraction efficiency can be as large as 9 9%. The availability of an extracted beam will enhance detector R&D st udies at Fermilab and give an additional boost to the U.S. participati on in the LHC experiments. As a second priority, small fixed target ex periments could be carried out. Crystal scrapers-deflectors would also work well for the LHC where background radiation due to a beam halo l oss could be reduced by the factor of 100.