Extraction from the Fermilab Tevatron using channeling with a bent crystal

Experiment 853 at Fermilab is approved to test the possibility of extracting very low intensity beams from the Tevatron using channeling in a bent crystal as the extraction device and RF modulations to move halo beam onto the crystal. The purpose of the experiment is to prove that the extraction technique is feasible, and that it does not create backgrounds for collider experiments which are unacceptable. In the first phase of the experiment, an unbent crystal has been inserted close to the beam at the site of the future bent crystal. In this paper we discuss the technological challenges of the bent crystal and measurements planned with both the unbent and bent crystals