1. Ian Bailey University of Liverpool / Cockcroft Institute UK Target Update EUROTeV: WP4 (polarised positron source) PTCD task I. Bailey, J. Dainton, L. Jenner, L. Zang (Cockcroft Institute / University of Liverpool) D. Clarke, K. Davies, A. Gallagher, N. Krumpa (CCLRC Daresbury Laboratory) C. Densham, M. Woodward, B. Smith (CCLRC Rutherford Appleton Laboratory) J.L. Fernandez-Hernando, D.J. Scott (CCLRC ASTeC Daresbury Laboratory / Cockcroft Institute) P. Cooke, P. Sutcliffe (University of Liverpool) In collaboration with Jeff Gronberg, David Mayhall, Tom Piggott, Werner Stein (LLNL) Vinod Bharadwaj, John Sheppard (SLAC)

2. UK Target R&D Involvement Target simulations (with DESY) –Detailed geometry for FLUKA (presented in target hall session) –Planned GEANT4 spin transport simulations –Eddy current simulations (Jim Rochford - this session) Photon Collimator simulations –Beginning FLUKA simulations –(Lei Zang, University of Liverpool) Target wheel prototyping (this talk) –Proposed 3 staged prototypes sited at DL –Pending funding Remote-handling solutions –RAL (presented in target hall session) Alternative target materials –Alternative metals, ceramics (alumina + zirconia), etc –RAL (work underway)

3. Proposed Timeline (100% funding scenario) Stage 1 Construct and test a prototype to establish the mechanical stability of the target wheel assembly in the field of a strong magnet. Does not include internal water- cooling channels. Does not include vacuum vessel or vacuum conditions. –Apr 07 - Design of first target prototype wheel complete. –May 07 - Infrastructure in place at Daresbury Laboratory. –Jun 07 - Design of target test rig and instrumentation complete. –Aug 07 - Construction of target test rig complete. –Aug 07 -Construction of first prototype complete. –Nov 07 - Initial testing of first prototype complete. –Feb 08 – All testing of first prototype complete. –Mar 08 - Data from first prototype fully analysed.

4. Proposed Timeline (100% funding scenario) Stage 2 Construct and test a prototype to demonstrate operation of the target assembly when cooling system is operated in vacuum conditions. Testing both with and without magnet depending on conclusions of stage 1. –Nov 07 – Design of second target prototype wheel complete. –Jan 08 - Design of upgraded target test rig and instrumentation complete. –Apr 08 - Construction of second prototype complete. –Apr 08 - Upgrade of target test rig complete. –Jul 08 - Initial testing of second prototype complete. –Oct 08 - All testing of second prototype complete. –Dec 08 - Data from second prototype fully analysed

5. Proposed Timeline (100% funding scenario) Stage 3 Construct and test a prototype to establish performance of the target cooling system with heat load. Using latest target design and latest capture optics design if appropriate / available. –Mar 08 - Identify possible technologies for simulating thermal load. –Aug 08 - Design of thermal load source and interface to test rig complete. –Nov 08 – Design of upgraded target test rig and instrumentation complete. –Nov 08 – Design of third target prototype wheel complete (if needed following stage 2). –Feb 09 - Upgrade of target test rig complete. –Mar 09 - Installation of thermal load in test rig complete. –Mar 09 - Construction of third prototype complete. –Jun 09 – Initial testing of third prototype complete. –Oct 09 – Final testing of third prototype complete. –Feb 10 – Data from third prototype fully analysed. We don’t expect 100% funding!

6. Stage 1 Prototype Target Wheel Sectional view 1m diameter wheel with simplified structure compared to current baseline target wheel. Optional cantilever drive shaft (deflection measurements) Consistent with water-cooling (to be confirmed by LLNL) Uses Rigaku ferrofluidic feedthrough and is consistent with Deublin water union. Motor being sized for rotation up to 2000rpm.

7. Stage 1 Prototype Target Wheel (Hub Detail) Detail showing drive shaft and wheel hub. Reducing drive shaft to 2” diameter allows use of standard feedthrough and water coupling at 2000 rpm.

8. Stage 1 Prototype Target Wheel and Test Magnet Sectional view

9. Test Magnet Default option is to use magnet already based at DL –GMW dipole electromagnet, model 3474-140 –Normally used for Hall probe calibration Possibility of s/c magnet from BINP? 1800 kg water-cooled adjustable pole gaps

10. Future PTCD Activities Target Prototyping Proposing 3 staged prototypes over 3 years (LC-ABD funding bid) Measure eddy current effects top priority major impact on design Test reliability of drive mechanism and vacuum seals. Test reliability of water-cooling system for required thermal load Develop engineering techniques for manufacture of water-cooling channels. Develop techniques for balancing wheel. First prototype mechanical deisgn progressing well. First prototype instrumentation and electronics design starting. Remote-handling design Essential that remote-handling design evolves in parallel with target design. Determines target hall layout and cost. Evaluaitng change-over times. Photon Collimator design Use realistic photon beam. Activation simulations (in collaboration with DESY). Thermal studies and cooling design. Variable aperture (optimise in association with beam jitter simulations)?