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Status of the Production Ring studies

WP4 Meeting, 8-9/11/10 INFN-LNL, Legnaro, Italy. Status of the Production Ring studies. Elena Benedetto NTU-Athens & CERN. Outline. The Production Ring Ionization cooling Status of the work Challenges (the gas jet target) Alternatives/deviations from original (Rubbia’s) idea

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Status of the Production Ring studies

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  1. WP4 Meeting, 8-9/11/10 INFN-LNL, Legnaro, Italy Status of the Production Ring studies Elena Benedetto NTU-Athens & CERN

  2. Outline • The Production Ring • Ionization cooling • Status of the work • Challenges (the gas jet target) • Alternatives/deviations from original (Rubbia’s) idea • Direct kinematics (pro/cons) • Using an FFAG • Summary

  3. or Canfranc Beta-Beams • Produce, accelerate and store b-decaying ions (8Li, 8B) for the production of a pure electron (anti-)neutrino beam • High flux required • High production rates • Less then 10% reach DR • @ source: 1014/s 8Li, 8B • 5 times more than 6He,18Ne

  4. stripper, target & absorber 7Li(d,p)8Li 6Li(3He,n)8B 7Li 6Li RF cavity Production Ring: the idea • 8Li, 8B isotopes • Originally introduced to overcome lack of 18Ne (maybe not the case any more) • Longer baseline for oscillation experiments • Studies started in 2009, within EUROnu • Production ring • Multi-passage through an internal target • Ionization cooling → C.Rubbia et al, NIM A 568 (2006) 475–487 → D. Neuffer, NIM A 585 (2008) 109 → Y.Mori, NIM A 562 (2006) 591

  5. Ionization cooling • Energy losses(dE/ds) in the target material (Bethe-Bloch) • Only longitudinal component recovered in RF cavities → Transverse emittance shrinks • Cooling in 6D • (dE/ds) ~ b-2smaller at higher energies → cooling not effective in longitudinal • need coupling between transverse and longitudinal: → Dispersion & wedge-shaped target Faster ions will travel on an outer orbit and see a larger target thickness → they will get more (dE/ds) Target: width @ closed orbit = 5 cm t = 0.289 mg/cm2 If angle = 20o → Dx> 24 cm

  6. Preliminary lattice RF cavity Target NOT OPTIMIZED YET M. Schaumann, CERN-THESIS-2009-128 • C=12m • normal-conducting magnets • Capacitive loaded RF cavity • Charge-exchange injection Li+1

  7. Tracking simulations 6° wedge target angle • Sixtrack • Tracking code @ CERN • Fully 6D, symplectic • Reads MADX lattice • Collimation version • Tracking large # of particles, • Interaction w. Collimators & special elements • Adapted to the Production Ring needs • i.e. Target implemented • BetheBloch, Straggling, Multiple Coulomb Scattering simple formula) • Coupling w. MonteCarlo code FLUKA ongoing → V.Vlauchoudis, D.Sinuela, E.B. (CERN)

  8. Main challenge of present design • High density gas-jet target (1019 atoms/cm2) in vacuum environment • Factor 104 missing !!! (from exisiting cluster-jet targets)

  9. Alternative solution…& questions • Solid/liquid target + Direct kinematics • Solid (how to remove heat?) or liquid (instabilities of jet?)? • How to separate products 8Li/8B from circulating D/3He? → angle & velocity of produced ions → do they exit the target? → do we need to stop ions & diffusion/effusion mechanism, or… ? • Lithium liquid target technology → see e.g. Y. Momozaki, J. Nolen, C. Reed, V. Novick, J. Specht. Development of a liquid lithium thin film for use as a heavy ion beam stripper. Journal of Instr., 4(04):P04005, 2009. → someone @ INFN (for neutron production)? • Which energy? → thickness + stopping power + cross section + rev frequency…

  10. …some (preliminary) answers • Direct kinematics +solid/liquid target → work done by T.Weber (student @ RTWH Aachen) • Factor 1000 gained • But still factor 10(100) missing • (assuming beam Nb=1012 ions) • The products • Will be emitted in a wide cone angle • And will exit the target (~10mm thick) • We may gain to go to higher energies (from 10 to 24 MeV) • Cross-section smaller • Can use “thicker” target • Rev frequency increases more • BUT also energy straggling increases !!! TO BE CHECKED

  11. Direct kinematics, results Torsten Weber ← 8Li production (D beam) ↓ 8B production (3He beam)

  12. Torsten Weber • 2-body kinematics • Geant4 simulation of the products

  13. Torsten Weber

  14. Using an FFAG ring • FFAGs (vs. Synchrotrons) • “Fixed Field Accelerating Gradient” • Combined function magnets, with fixed magnetic field • Large acceptancefor both horiz.(~10-3) and longit.(<10%) • no need of (dp/p) cooling • For the “scaling FFAG” it is Q’~0 • Contacts with Y.Mori(KURRI, Osaka) • Proton FFAG with internal Be target for BNCT • They have a running machine! w. similar parameters • First attempt to use i-coolingNIM A 562 (2006) 591

  15. Schematic layout of FFAG-ERIT K.Okabe et al, IPAC10, EPAC08,... FFAG-ERIT @ KURRI (Osaka)

  16. FFAG-ERIT @ KURRI (Osaka) K.Okabe

  17. What if I could use ERIT for my ions • Same Br=0.48 Tm • Looks feasible! (even better performance than actual configuration) • Turned out we could actually do an experiment!!! (only for D beam)

  18. Possibility for an experiment • To prove that ionization cooling works • It will be the first time in the world!!! • Goal: keeping beam for ~10’000 turns • (not interested in production intensity) • Accelerator is there • Need to check RFQ with D- • Target & detector to be built !!! • Should to be “cheap” and in short timescale

  19. Summary • Production ring for “high Q” isotopes 8Li/8B • Uses internal target & ionization cooling • Preliminary design, tracking exist • Still a lot of R&D for afeasible solution (enough flux) • e.g. Existing gas-jet targets cannot reach the densities proposed in [C.Rubbia, et. al] in a vacuum environment • Liquid Li target and D/3He beam maybe solution • Feasibility studies started • Production rates look promising • What about target technology? • Possibility of i-cooling experiment at ERIT-FFAG

  20. Questions • The target: • How to make solid Lithium target (for FFAG experiment?) • Need to deposit Li on Carbon or Mylar substrate? • Or use some compound? • The final target will probably be liquid “waterfall” • Due to heat deposition constrains • Or maybe solid “renovating” target • I have some references but if you know of existing work… • What about liquid Deuterium or 3He instead? • The detector: • How to detect Li production (for FFAG experiment) ? • E,DE detector, scintillator or …

  21. Back-up slides

  22. Cooling rates and equilibrium emittance (1) Damping time Equilibrium emittances ex~90 mm ey~11 mm

  23. Cooling rates and equilibrium emittance (2) straggling <0 → blow-up <0 !!!! If now we introduce Dispersion (and a triangular target shape): at a different orbit Dx=D Dp/p

  24. 0.4 for 6Li 0.01 for 7Li Cooling rates and equilibrium emittance (3) If now we introduce Dispersion (and a triangular target shape):.. Cooling can be transferred from transverse to longitudinal thanks to Dispersion + triangular target can also introduce coupling x-y Since sum of the three partition number is always the same, is computed for Dx=0: Due to Bethe-Bloch shape, NO possibility to effectively cool → but only to keep a constant emittance or not to heat it “too much”

  25. Production: requirements • Summing-up all losses in accelerator chain • Source + Linac RFQ: ~70% • RCS injection+capture: 30% • Decay losses: 20%(18Ne) 50%(6He) • Momentum collimation: up to 50% • Only 8.4%(18Ne)-5.2%(6He) of produced ions is stored in the DR We need to produce (and collect!!!) 2-3 1013 (x5) ions/s

  26. What if I could use ERIT-FFAG for my ions Stolen from K.Okabe’s presentation

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