• S. Hesselbach, G.A. Moortgat-Pick
  Durham University, Durham
• I.R. Bailey, L.J. Jenner
  Cockcroft Institute, Warrington, Cheshire
• J.-L. Fernandez-Hernando
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• S. Riemann, A. Schälicke, A. Ushakov
  DESY Zeuthen, Zeuthen
• J. Rochford
  STFC/RAL/ASTeC, Chilton, Didcot, Oxon
• L. Zang
  The University of Liverpool, Liverpool

Energy deposition in the conversion targets of positron sources for future linear colliders will lead to thermal shock waves which could limit the targets' lifetimes. For the International Linear Collider baseline source, we have studied the energy deposition in a target taking the higher harmonics of the undulator radiation fully into account and applying hydrodynamical models for the resulting heat flow to determine the thermal stress in the target and to assess its survivability.