Increased Intensity Heavy Ion Beams at ORIC with Cryopumping
Previously reported measurements of heavy ion beam attenuation with pressure have demonstrated the need for additional pumping in the circulating beam region of the Oak Ridge Isochronous Cyclotron (ORIC). Two specially designed 20°K cryopumps, located on the magnet poles, have increased the pumping speed in the circulating beam region by about a factor of 3. This has led to increased intensity for beams of heavy ions of elements that can be condensed by the cryopumps (e. g., oxygen, nitrogen, etc.). The improved vacuum has led to an increased understanding of a beam loss in the internal region of the cyclotron. Measured cross sections for beam loss and the cross section energy dependence have been determined.