• V.A. Lebedev, J.-F. Ostiguy, N. Solyak
  Fermilab, Batavia
• A.V. Aleksandrov, A.P. Shishlo
  ORNL, Oak Ridge, Tennessee

A beam loss in the superconducting part of the SNS linac has been observed during its commissioning and operation. Although this loss does not prevent the SNS high power operation it results in an almost uniform irradiation of linac components and increased radiation levels in the tunnel. A multi-particle tracking could not explain the beam loss and its dependence on the machine parameters. It was recently found that the loss is related to the intrabeam particle collisions resulting in a stripping of one of two H^- ions. The paper describes experimental observations and corresponding calculations of the intrabeam stripping.