• J. Gronberg, A. Abbott, C.G. Brown, J.B. Javedani, W.T. Piggott
  LLNL, Livermore, California
• J.A. Clarke
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire

The positron source at a future TeV scale electron linear collider will need to generate positrons at a rate two orders of magnitude larger than have been previously achieved. We report on a design of a 3.5 Tesla pulsed flux concentrator magnet which uses liquid nitrogen cooling of the flux concentrator plates to reduce the electrical resistance leading to reduced energy deposition and the ability to generate the required 1 ms pulse duration. This magnet can double the collection efficiency of positrons emitted from the target.