J. C. Sheppard SLAC September 29, 2006

1. ILC Positron TDR and R&D Collaboration Meeting 1: OxfordSummary Discussion and Meeting CritiqueDiscussions 9 and 10 J. C. Sheppard SLAC September 29, 2006 1

2. Discussion 9: Z2 Summary ILC Positron System Design and R&D Goals in Support of the TDR Z2: Meeting Summary Discussion: Action Items Z3: Meeting Format Discussion: What Works What Does Not Work What Do We Do Differently 2

3. Discussion 9: Z2 Summary ILC Positron System Design and R&D Goals in Support of the TDR Topic leaders will write a short summary for each meeting with an emphasis on accomplishments and action items: ~One Page The meeting chair is responsible for collecting the topical summaries and writing an overall summary of progress and expected goals by the time of the next meeting. 3

4. Discussion 9: Z2 Summary • Topic Action Items: • Target Systems Ian Bailey/Tom Piggott • Looking to urgently prototype target wheel in UK. No one else currently requesting funding. • Test first prototype baseline target at DL in Summer 2007. • LLNL, Liverpool, DL to present p’type drawings at Feb ’07 meeting. • Estimate force on wheel from pulsed OMD. Jeff to coordinate. • Specify how prototyping plans depend on outcome of OMD studies. • RAL/DL report on impact of remote-handling strategies (see target hall session) on target design at Feb ’07 meeting. • Number of R&D cycles, milestones and timeline will be agreed by main participants by Dec ’06. John S to coordinate. • RAL/Liverpool to investigate materials for the target rim and provide material spec sheets for Feb ’07 meeting. Ian will coordinate. • Viability of beam windows (eg between target and accelerating cavity) needs to be definitively investigated. Plan needs to be in place by Dec’06. Vinod will coordinate. • Viability of liquid metal target depends on proven design of suitable beam window . • Cornell may wish to report on this issue at the Feb ’07 meeting. 4

5. Discussion 9: Z2 Summary • Topic Action Items: • OMD Jeff Gronberg • Need to answer question of immersion effects in order to make OMD choice: need simulation benchmarked with experiment • For SC solenoid need to understand radiation, power depo conditions and rad damage (simulation) • For pulsed OMD need development plan • Investigate range of zero field on target OMDs (MK at KEK) • Report results and plans of spinning wheel experiments at Feb meeting 5

6. Discussion 9: Z2 Summary • Topic Action Items: • Capture RF Juwen Wang • Progress. • Five-cell L-Band SW test structure for capture section is under fabrication. Almost all parts and subassemblies are either done or in process. Still a lot of work need to be done in order to complete the final assembly by the end of 2006 or the beginning of 2007. • All of five sets of parts for L-Band RF windows are in hands. A completed window is under cold test. • Five vacuum flanges for test structures and Couplers have been completed. • 2. In order to have a solid design for both positron and electron sources, we should fund a R&D program for L-Band TW structures. • There are many challenges in both electrical, mechanical designs as well as fabrication aspects: • They are long, the balanced cooling and pumping systems needs to be carefully studied and inductive brazing technique needs to be practiced at SLAC. • They have low group velocity (as low as 0.16%c), the impact of big transient effects needs to be investigated and tested. • They work at long beam pulses (1 ms), the operational stabilization needs to be studied and tested. 6

7. Discussion 9: Z2 Summary • Topic Action Items: • Target Hall Vinod Bharadwaj • More activation/damage calculations • Identify what numbers are needed from the calculations • Figure how to do the simulation – which program(s) etc. • identify people to do the simulations • include detailed layout of hardware: • OMD, SW RF, TW RF, solenoids, shielding • Define target hall dimension requirements • target hall occupancy needs • needed shielding • what is in the hall and what is on the surface • scenarios for all the needed repair/replacement operations • KAS target hall • Does ILC plan to have a central hot cell facility? • e+ , dumps etc. • will it be useful for the positron stuff • Re-visit two/one target requirement (availability, R&R time,……) 7

8. Discussion 9: Z2 Summary • Topic Action Items: • Undulator Scheme Jim Clarke • Two sets of conflicting undulator parameters are proposed – ‘high K’ and ‘low K’. This should be resolved as a priority. Start to end simulations carried out with a benchmarked code are needed from the entrance of the undulator to after the positron capture section to understand the differences. Results to be reviewed at the next meeting. • In the meantime the UK undulator parameters are adopted as the baseline. Period = 11.5mm, beam aperture = 5.85mm, Kx = Ky = 0.92. • UK to prototype 4 m module in calendar 2007. Beam test plan should be reviewed at the next meeting. • Need magnetic measurements plan for the long prototypes • UK group to review 80% design margin by Feb 07. 8

9. Discussion 9: Z2 Summary Topic Action Items: F. Laser-Compton Scheme Masao Kuriki Develop full design which is compatible with current ILC design: • full source accelerator design: OMD, rf, yield calcs • Simulation of compton ring dynamics, incl nonlinear beam dynamics • Simulation of e+ stacking in the ILC DR. Optical cavity and laser experiments „Schedule“ for compton scheme development, now thru completion: how to we get from here to there 9

10. Discussion 9: Z2 Summary • Topic Action Items: • Conventional Scheme Bharadwaj/Sheppard • nothing to report 10

11. Discussion 9: Z2 Summary • Topic Action Items: • Accelerator Physics Gudi Moortgat-Pick • Collect into a single report dilution and depolarization studies; what additional issues? • Propose how to do commissioning w/o Keep Alive Source • Start-to-end tracking w/ spin tracking, schedule • Fix GigaZ parameters • Optical Deck for specifications and tolerances • Status of e+ tracking studies incl/ e- thru undulator insertion (ILC low emit folks,….) 11

12. Discussion 9: Z2 Summary • Topic Action Items: • Polarization Sabine Riemann • Report on tools and scope of activities at Feb. meeting 12

13. Discussion 9: Z2 Summary ILC Positron TDR and R&D Collaboration Meeting 1: Oxford Thanks for coming to this meeting and a special thanks to Yury Ivanyushenkov and Glyn Northing for organizing us and to RAL for hosting us Next Meeting: Asia, M. Kuriki prior to and in association with February GDE Beijing Meeting 13

14. Discussion 10: Z2 Summary ILC Positron System Design and R&D Goals in Support of the TDR Discussion: Every thing is open for discussion: format, discussion leaders, topics, organization, schedule, ILC Will have a session on Friday to discuss how this meeting has gone; what changes are required; what went well; what is clearly not working;……. I think that it will take about 3 meetings (1 year ) to settle out on this process (allow phone and video links to the 3 annual meetings Gudi Mortgat-Pick makes and maintains group mail server Declare a spokesman for collaboration: J Sheppard, for the time being 14

15. Discussion 10: Z2 Summary ILC Positron System Design and R&D Goals in Support of the TDR Discussion, comments, suggestions What Works What Does Not Work What Do We Do Differently 15