Generation and diagnostics of uncaptured beam in the Fermilab Tevatron and its control by electron lenses

In the Collider Run II, the Tevatron operates with 36 high intensity bunches of 980 GeV protons and antiprotons. Particles not captured by the Tevatron RF system pose a threat to quench the superconducting magnet during acceleration or at beam abort. We describe the main mechanisms for the origination of this uncaptured beam, and present measurements of its main parameters by means of a newly developed diagnostics system. The Tevatron Electron Lens is effectively used in the Collider Run II operation to remove uncaptured beam and keep its intensity in the abort gaps at a safe level.