1. Oct. 6, 2006 1 ILC Positron Source Group Meeting Short report by S. Riemann 27 - 29 September 2006, RAL

2. Oct. 6 2006 2 Goal of the Workshop facilitate the development of the collaboration to design and carry out R&D for the ILC Positron System organize the international activities  essential work for the TDR accomplished on a priority basis  reduce unnecessary duplication and activities not relevant to the ILC e+ system requirements Regular meetings to discuss status, progress, and plans for the various positron system design and R&D

3. Oct. 6 2006 3 Why? How? At the moment the positron source groups are a loose confederation of interested participants Need a collaboration that takes responsibilities for our activities Categorize activities in topics  discuss its contribution to e+ production; technical feasibility; need for design, simulation, R&D, and prototyping status of each activity should be discussed including the availability of resources (people and funding), milestones, schedules, and impediments

4. Oct. 6 2006 4 Topics Target Systems Ian Bailay/Tom Piggot OMD Jeff Gronberg Capture RF Juwen Wang Target Hall Vinod Bharadwaj Undulator Scheme Jim Clarke Laser Compton Scheme Masao Kuriki Conventional Scheme Bharadwaj/Sheppard Accelerator Physics Gudi Moortgat-Pick Polarisation Sabine Riemann Spokesman of the collaboration: J. Sheppard

5. Oct. 6 2006 5 This Workshop http://www.te.rl.ac.uk/ILC_Positron_Source_Meeting/ Undulator Scheme Laser Compton Scheme Target Station/Target Damage OMD/AMD Accelerator Physics target hall design, activation & remote handling

6. Oct. 6 2006 6 UK Undulator Prototyping R&D Goal Develop reliable magnetic modelling technique Develop undulator manufacturing technique Manufacture and test first full scale undulator module (4m) by end of July 2007 Beam test of 4-m undulator module at Daresbury Lab – fall 2007. Pre-production prototype – 2008-09. Y. Ivanyushenko

7. Oct. 6 2006 7 Prototypes family Y. Ivanushenko

8. Undulator 4m module Two sections of the undulator magnet He bath vesselThermal shield Cold Mass

9. Oct. 6 2006 9 LAL Activities (A. Variola) R&D on a high finesse optical cavity: Goals: 1) operate a very high finesse Fabry-Perot cavity in pulsed regime - 2 mirrors cavities Gain: 10 4 -10 5 - Started in Sept 2005 2) reduction of the laser beam size (waist) - 4 mirrors non-planar cavity - Setup started in Sept. 2006 starting to evaluate a new scheme for the Compton source, (ERL based), the new idea seems promising Studies on channeling for the conventional solution

10. Oct. 6 2006 10 Optical Setup at Orsay

11. Oct. 6 2006 11 Experiment setup. Laser & Cavity installed Present status

12. Oct. 6 2006 12 Target Systems  U Liverpool (EUROTeV) working in collaboration with SLAC and LLNL  Developing water-cooled rotating wheel design.  0.4 radiation length titanium alloy rim.  Radius approximately 1 m.  Rotates at approximately 1000 rpm. Constraints: Wheel rim speed determined by thermal load and cooling rate Wheel diameter determined by radiation damage and Materials fixed by thermal and mechanical properties and pair- production cross-section I. Bailey

13. Oct. 6 2006 13 Radiation Aspects (Target) Material Damage Material Activation  remote handling - see also talk of T. Broome Studies done by A. Ushakov: - activation and target damage - activity and dose rates for different source types (see also EPAC paper)

14. Oct. 6 2006 14 Target Damage A. Ushakov

15. Oct. 6 2006 15 Target and capture section AMD Design Further evaluation of pulsed/continuous design. Look in more detail at cooling and stress issues. Magnet Loading on Wheel Try to bring simulations and experimental data closer. Look at required motor power, additional heat input. Overall design (undulator, collimator, target,AMD/OMD, …)

16. Oct. 6 2006 16 J. Gronberg

17. Oct. 6 2006 17 J. Gronberg

18. Oct. 6, 2006 18 Eddy Current Simulations LLNL - preliminary Initial “Maxwell 3D” simulations by W. Stein and D. Mayhall at LLNL indicate: ~2MW eddy current power loss for 1m radius solid Ti disc in 6T field of AMD. <20kW power loss for current 1m radius Ti rim design. However - Simulations do not yet agree with SLAC rotating disc experiment. 8” diameter Cu disc rotating in field of permanent magnet. Possibility of OPERA-3D simulations at RAL. See AMD Session

19. Oct. 6 2006 19 Issues for the rotating target A. Mikhailichenko Model erected (using FlexPDE Solutions)  field calculations performed  consequences for shower loss and transverse deflection fields and pulsed torques in pulsed solenoid case

20. Oct. 6 2006 20 A. Mikhailichenko

21. Oct. 6 2006 21 A. Mikhailichenko

22. Oct. 6 2006 22 Start-to-end Model of the Positron Source e- Undulator Electron Gamma Shower code: EGSnrc Particle dynamic code: PARMELA Analytical + Monte carlo Wai Gai et al. studied the e+ yield in the immersed target case. Including both polarized (60%) and unoplarized cases. Many undulator and drive beam parameters investigated. Also studied the drive beam jitter and found it is not a severe problem. A lot more cases to be done.

23. Oct. 6 2006 23 Topic leaders are working on summaries and to-do lists Next meeting in ~4 months (February) Main work: parameter lists, target studies, …, reliable working scheme (Compton)  redo simulations - for an overall design of the source