1. Development of a Positron Production Target for the ILC Positron Source Capture Optics Positron beam pipe/ NC rf cavity Target wheel Vacuum feedthrough Motor Photon beam pipe  Water-cooled rotating wheel.  0.4 r.l. titanium alloy rim.  Radius ~1 m.  Rotates at ~1000 rpm. The University of Liverpool, LLNL and SLAC are carry out design studies of the ILC e + source conversion target. Project Overview LLNL - draft design Undulator Photon Beam (2) *  “Proportional to undulator length” Target Systems Key sub systems Target wheel Drive system Cooling system Vacuum system Remote-handling system Diagnostic and control systems Not to scale! For illustration only. Target Wheel Design LLNL - draft design Numbers refer to LLNL study of earlier solid- disc design with 220 kW photon beam. Eddy Current Simulations LLNL - preliminary Initial “Maxwell 3D” indicate: ~2 MW eddy current power loss for 1m radius solid Ti disc in 6T field of AMD. <20 kW power loss for current design. Simulations yet to be calibrated to SLAC rotating disc experiment. Power Deposition & Cooling Approximately 10% of photon beam power is deposited in target wheel LLNL - draft design Water fed into wheel via rotating water union on drive shaft. Remote-Handling Each hot cell consists of: Super-structure and shielding 2 lead glass windows (1m x 1m viewing area, 1m thick) 2 pairs of master-slave manipulators In-cell crane Ventilation system Camera and sound system (8 videos cameras) Posting port Miscellaneous tools… Photon beam Full maintenance remote- handling concept. Two hot cells. Based on ISIS second target station. Remote Handling (2) Alternative single hot cell design. Suited to two targets in series. P. Sutcliffe, University of Liverpool. Cheapest option may be to move any faulty target to a holding cell until ‘cool’ enough to be handled manually. Will depend on component reliability. Summary and Outlook Prototypes will be developed to demonstrate: Stability of rotating target Reliability of drive mechanism and vacuum seals. Rotation of target in B field of capture optics. Reliability of water- cooling system for required thermal load Engineering techniques for manufacture of water- cooling channels. A design has been developed for a conversion target that satisfies the requirements of the ILC positron source. Simulations and modelling of the target systems is ongoing. A remote-handling design is being investigated. Work supported by the Commission of the European Communities under the 6 th Framework Programme “Structuring the European Research Area”, contract number RIDS-011899. This work was performed under the auspices of the U.S. Department of Energy by the University of California,Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48. Work supported by the U.S. Department of Energy under contract number DE- AC02-76SF00515. Undulator Photon Beam Undulator K=1, 1cm period, 100m Nominal ILC parameters. Neglect collimation. Target ~500 m downstream. Total photon beam power ~145 kW Average photon energy ~ 13MeV Beam spot rms ~1 mm Simulations using SPECTRA I.R. Bailey 1,3,V. Bharadwa,j 4,P. Cooke 3,J.B. Dainton 1,3, J. Gronberg 2,D. Mayhall 2,T. Piggott 2,D.J. Scott 1,3,J. Sheppard 4,W. Stein 2,P. Sutcliffe 3 1 Cockcroft Institute, Daresbury Laboratory, Warrington, Cheshire, WA4 4AD, UK. 2 Lawrence Livermore National Lab, Livermore, CA 94551, USA. 3 Department of Physics, University of Liverpool, Liverpool, L69 7ZE, UK. 4 Stanford Linear Accelerator Cente, PO Box 20450, Stanford, CA 94309, USA. Conversion Target (0.4X 0 Ti) Polarised Positrons (≈ 5 MeV) Helical Undulator (≈ 200 m) Photon Collimator Photons(≈ 10 MeV ) Electrons (150 GeV) Baseline layout of ILC with undulator at 150GeV position in main linac. Positron Source Tim Broome, RAL