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POSIPOL workshop 2010

POSIPOL workshop 2010. A brief overview. L. Rinolfi. Short history. POSI TONS POL ARISÉS. April 2006. (in French).

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POSIPOL workshop 2010

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  1. POSIPOL workshop 2010 A brief overview L. Rinolfi

  2. Short history POSITONS POLARISÉS April 2006 (in French) POSIPOL is a series of workshops dealing with the physics aspects, the design issues, and the open questions concerning polarized positron sources in the framework of the ILC and CLIC projects. POSIPOL 2010 was the fifth workshop following: POSIPOL 2006 at CERN Chair: L. Rinolfi POSIPOL 2007 at LAL-Orsay Chair: A. Variola POSIPOL 2008 at Hiroshima Chair: M. Kuriki POSIPOL 2009 at IPNL-Lyon Chair: X. Artru POSIPOL 2010 at KEK Chair: T. Omori

  3. Participants POSIPOL 2010 19 Institutes (from America, Asia, Europe): ANL, BINP, BNL, CERN, DESY, Hiroshima University, IHEP, IPNL/IN2P3, INFN, ISIR, JAEA, KEK, LAL, LLNL, NSC/KIPT, RISE, Tokyo University, Tomsk, Waseda University. 44 participants (4 from CERN): M. Petrarca, L. Rinolfi, A. Vivoli, F. Zimmermann

  4. Scope of the workshop POSIPOL 2010 31/May-2/June, KEK, Tsukuba T. Omori POSIPOL 2010 focuses, as in the previous years, on polarized positron sources for ILC and CLIC via Laser-Compton and via undulator-radiation, but also extends topics as target discussions particularly relevant for the conventional positron sources. For these later, various solid and liquid target materials and pseudo-conventional using channeling are topics of the workshop. POSIPOL 2010 deals also with various high intensity positron sources for other future collider projects, such as B-factories and LHeC.

  5. e-/e+ Collider B-Factory ILC-Test Facility Photon-Factory Japan Proton Accelerator Research Complex : J-PARC Kamioka Tokai Tsukuba Tokyo Narita Mt. Fuji

  6. News from IPNS director Koichiro Nishikawa IPNS = Institute of Particle and Nuclear Study • The JAHEP community’s master plan • Highest priority is given to ILC • Before ILC, promote flavor physics at KEKB and J-PARC • Action before the ILC approval • ILC R&D • Completion/commissioning and continuous improvementsof J-PARC • Upgrade of KEKB/Belle • Collaboration in LHC/ATLAS

  7. What was discussed Physics: (1 talk) Status of e+ sources for colliders :(4 talks: ILC, CLIC, KEKB, BEPC) ILC-CLIC working group : (1 talk) Hybrid and channeling e+ sources (CLIC&ILC): (7 talks) Compton-based e+ sources for colliders (ILC&CLIC):(10 talks) Undulator-based e+ source for ILC:(4 talks) Compton-based X-ray and gamma-ray sources : (4 talks) (including applications to material physics) Liquid Pb and Pure Conventional e+ sources (ILC): (3 talks)

  8. Why polarized e- and e+ beams ? G. Moortgat-Pick

  9. LC Strategy G. Moortgat-Pick

  10. Arguments for polarized e+ G. Moortgat-Pick

  11. ILC - RDR design Kaoru Yokoya • Undulator • Located at 150GeV point in electron linac • Helical • Pitch = 1.15cm, B=0.86T (K=0.92) • Beam aperture 5.85mm • Target • Ti Alloy • Wheel with radius 1m, thickness 1.4cm • Rotating speed 100m/s (2000rpm) • Capture • Flux concentrator • KAS (Keep Alive Source) • Independent, conventional • 10% intensity

  12. ILC - SB2009 Design Not yet the baseline Kaoru Yokoya • 1) Replace flux concentrator with QWT. Accordingly, undulator length 147m231m to compensate for the less efficient capture. • .This does notmean QWT+231m undulator is less risky than FC+147m undulator • (Just because feasibility demonstration of FC is more costly) • . Higher target load due to longer undulator (x 1.6) • 2) Move undulator to linac end • One MPS • Shorter positron transport • No deceleration needed • Everything dirty is concentrated near the center of the complex (BDS, DR, injectors) • 3) Keep Alive Source (~10% intensity) replaced by Auxiliary Source (few % intensity) which shares the target, capture system, etc with the undulator source

  13. CLIC - CDR Design - 3 TeV at PDR injection at Source e+ PDR 2.86 GeV 4.6x109 e+ / bunch Injector Linac 2.66 GeV unpolarized e+ e-/g Target polarized e- g/e+ Target Thermionic e- gun Pre-injector e+ Linac 200 MeV Primary e- Beam Linac 5 GeV Bunching system 2 GHz AMD 2 GHz

  14. SuperKEKB e+ source upgrade T. Kamitani

  15. Status of SuperB factories T. Kamitani

  16. Status of BEPC II G. Pei Impressive progress from BEPC to BEPC II at Beijing

  17. R&D plan for e+ studies “ILC-CLIC e+ generation” working group Important reduction of resources have registered in several institutes. Therefore the ILC/CLIC work plan is reviewed according to the available resources from the different institutes around the world and the possible contributions are presented. Institutes: 5 from Asia, 6 from USA and 9 from Europe A review of the milestones will be done at the coming LC workshop in October 2010 at Geneva.

  18. Channeling of charged particles S. Dabagov

  19. Simulations for hybrid sources O. Dadoun Amorphous target Crystal target e+ e- Photons => will be included into G4 and X. Artru simulation

  20. Channeling simulations Comparison of 2 codes O. Dadoun

  21. Hybrid source advantage R. Chehab • CLIC: incident beam: 5 Gev; t1=1.4 mm; t2=10 mm • ACCEPTED POSITRON YIELD • * For an incident e- beam with s = 1 mm => h = 1 e+/e- • * For an incident e- beam with s = 2.5 mm => h = 0.9 e+/e- • PEDD (Peak Energy Deposition Density) • Assuming an incident e- pulse of 2.34 1012 e-, we have : • CRYSTAL AMORPHOUS • PEDD/e- PEDD/total PEDD/e- PEDD/total • (GeV/cm3/e-) J/g (GeV/cm3/e-) J/g • s=1mm 2 38 2.5 48.5 • s=2.5mm 0.35 6.8 0.8 15.5 • An entirely amorphous target, 9 mm thick, with the same incident e- beam would have provided the same accepted yield and a PEDD of 150 J/g (s=1mm) or 40J/g (s=2.5 mm). This shows the advantages of an hybrid scheme leading to a unique target with a PEDD < 35 J/g using an e- beam with s= 2.5 mm.

  22. CLIC Injector Linac A. Vivoli e+ in PDR: 2720; Yield e+/e- =0.453

  23. Set up SiteLooking up from Down stream KEKB Linac Tests for e+ production from hybrid targets

  24. Zoom on e+ crystal target

  25. e+ yield at KEKB Linac Experimental results from hybrid targets T. Takahashi black: 1mm W crystal + 8mm W amorphous conventional 8mm 3.4 enhancement hybrid onaxis hybrid offaxis Preliminary conventional 18mm e+ yield (ADC counts)

  26. Why Compton scheme ? • Method to obtain polarized e+ (up to 90%) • Dedicated low energy e- beam (no inter-system dependence) • No issue for low energy scan operation • Technology feasibility can be evaluated before final construction BUT still some difficulties: • Laser ( high power and high quality) • Optical cavity • Electrons: Ring-based, ERL-based, Linac-based Compton scheme • Positron stacking required

  27. Optimal Compton ring E. Bulyak

  28. Optical cavity with 4 mirrors F. Zomer For polarized e+ Compton source at ATF/KEK Cavity arrived yesterday at Narita

  29. Compton with multiple IP I. Chaikovska Characteristics for simulations of polarized gammas source

  30. Results for e+ production I. Chaikovska

  31. e+ stacking simulations F. Zimmermann Based on 2 CLIC stacking rings option 312 bunches / train 1 train / ring e+ PDR 400 m 50 Hz new CLIC scheme 0.5 ns 312 bunches spaced by 0.5 ns => 155.5 ns / turn Stack in the same bucket every 69th turn Number of stacking in the same bucket 1864 69 x 1864 = 128 617 turns 128 617 x 155.5 ns = 20 ms SR 1 SR 2 25 Hz 47 m 47 m CLIC stacking rings must have much shorter damping times ~50 ms and higher RF voltage (35 MV) than SLC damping rings ERL 32 ns Large off-momentum dynamic aperture up to dinj~9% (!) is also required Preliminary simulations with semi-optimized parameters indicate >95% stacking efficiency

  32. Linac-based Compton scheme Polarized g-ray beam is generated in the Compton back scattering inside optical cavity of CO2 laser beam and 6 GeV e-beam produced by linac. Laser cavity needs R&D. First tests of the laser cavity: g to e+ conv. target 60MeV g beam 3% over 1 ms 6GeV e- beam 30MeV e+ beam ~2 m V. Yakimenko Conventional Non-Polarized Positrons:

  33. Compton Linac e+ sources V. Yakimenko Proposed parameters are in black, Optimistic numbers are in Red

  34. Summary from BNL V. Yakimenko • There is no funding for ATF to work directly for ILC, CLIC or SuperB: • development of CO2 regenerative cavity, • high repetition rate operations • There is an active program to use highest Compton X ray peak flux for single shot user experiments: • Started with High efficiency conversion ~1x ray / 1 electron, Spatial distribution of second harmonic (U. Tokyo, KEK) • Phase contrast imaging (INFN) • Diffraction scattering on the crystal (UCLA) • There is an active CO2 development program at ATF • required for ILC pulse parameters and amplifier bandwidth is demonstrated • Gradual increase of the single pulse intensity is the main goal.

  35. Summary from ANL W. Gai Polarization issues with undulator based e+ source Undulator 100 m long and drive beam energy 150 GeV Collimator distance = 700 m Collimator iris = 2.5 mm 1) Higher harmonics are important and can influence the overall polarization. 2) Polarization and yields are always conflicting, compromises need to be made. 3) Lower energy drive beam (150 GeV) is more practical in achieving high degree polarization than higher drive beam energy (250 GeV).

  36. Shock wave on BN window T. Omori Experiment performed at KEKB

  37. Summary from KEK T. Omori

  38. Workshop achievements 1) Review e+ sources of colliders 2) “ILC-CLIC e+ generation” working group Set new milestones 3) Hybrid and channeling e+ sources Review design progress for CLIC baseline source Review R&D status and set next goals 4) Compton Review R&D status and design progress Review the industrial, medical, material applications 5) Undulator Review R&D status and design progress Prepare re-baseline for ILC baseline source 6) Liquid Pb and Pure Conventional e+ sources Review R&D status and set next goals

  39. ILC NewsLine Report http://www.linearcollider.org/newsline/archive/2010/20100610.html

  40. Conclusion Apologizes for the talks which have not been mentioned in this Summary All talks from the following link: http://atfweb.kek.jp/posipol/2010/index.html POSIPOL 2011 at Beijing hosted by IHEP POSIPOL 2012 at Hamburg hosted by DESY

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