A silicon crystal was used to channel and extract 70 GeV protons from the U-70 accelerator with an efficiency of $85.3\pm 2.8\%$, as measured for a beam of $\sim {10}^{12}$ protons directed towards crystals of $\sim 2\mathrm{mm}$ length in spills of $\sim 2\mathrm{s}$ duration. The experimental data follow very well the prediction of Monte Carlo simulations. This demonstration is important in devising a more efficient use of the U-70 accelerator in Protvino and provides crucial support for implementing crystal-assisted slow extraction and collimation in other machines, such as the Tevatron, RHIC, the AGS, the SNS, COSY, and the LHC.

• Received 12 April 2001

DOI:https://doi.org/10.1103/PhysRevLett.87.094802