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Status of the beta-beam study

This article provides an update on the progress and challenges of the Beta-Beam study for the EURISOL facility. It includes information on the conceptual design, performance goals, and cost estimates of the facility. The article also discusses the challenges in production, intensity distribution, power losses, dynamic vacuum, collimation, and ionization cooling.

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Status of the beta-beam study

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  1. Status of the beta-beam study Mats Lindroos on behalf of the EURISOL beta-beam task The beta-beam task, EURISOL

  2. Outline • The beta-beam • Progress on a conceptual design • EURISOL beta-beam facility • Challenges for the beta-beam • Conclusions The beta-beam task, EURISOL

  3. The EURISOL beta-beam facility! The beta-beam task, EURISOL

  4. Beta-beam R&D • The EURISOL Project • Design of an ISOL type (nuclear physics) facility. • Performance three orders of magnitude above existing facilities. • A first feasibility / conceptual design study was done within FP5. • Strong synergies with the low-energy part of the beta-beam: • Ion production (proton driver, high power targets). • Beam preparation (cleaning, ionization, bunching). • First stage acceleration (post accelerator ~100 MeV/u). • Radiation protection and safety issues. • Subtasks within beta-beam task • ST 1: Design of the low-energy ring(s). • ST 2: Ion acceleration in PS/SPS and required upgrades of the existing machines including new designs to eventually replace PS/SPS. • ST 3: Design of the high-energy decay ring. • Around 38 (13 from EU) man-years for beta-beam R&D over next 4 years (only within beta-beam task, not including linked tasks). The beta-beam task, EURISOL

  5. Design study objectives • Establish the limits of the first study based on existing CERN accelerators (PS and SPS) • Freeze target values for annual rate at the EURISOL beta-beam facility • Close cooperation with neutrino physics community • Freeze a baseline for the EURISOL beta-beam facility • Produce a Conceptual Design Report (CDR) for the EURISOL beta-beam facility • Produce a first cost estimate for the facility The beta-beam task, EURISOL

  6. Challenges for the study • Production • Charge state distribution after ECR source • The self-imposed requirement to re-use a maximum of existing infrastructure • Cycling time, aperture limitations etc. • The small duty factor • The activation from decay losses • The high intensity ion bunches in the accelerator chain and decay ring The beta-beam task, EURISOL

  7. Intensity distribution during acceleration Bunch 20th 15th 10th 5th 1st • 30% of first 6He bunch injected are reaching decay ring • Overall only 50% (6He) and 80% (18Ne) reach decay ring • Normalization • Single bunch intensity to maximum/bunch • Total intensity to total number accumulated in RCS total The beta-beam task, EURISOL

  8. Power losses - comparison Power loss per unit circumference of a machine Nucleon losses compared • PS and SPS comparable for CNGS and bb operation • PS exposed to highest power losses The beta-beam task, EURISOL

  9. Dynamic vacuum • Decay losses cause degradation of the vacuum due to desorption from the vacuum chamber • The current baseline includes the PS, which does not have an optimized lattice for unstable ion transport and has no collimation system • The dynamic vacuum degrades to 10-5 Pa in steady state (6He) • An optimized lattice with collimation system improves the situation by two orders of magnitude P. Spiller et al., GSI The beta-beam task, EURISOL

  10. 6He Ionsstored/ionsinjected merges 18Ne Ionsstored/ionsinjected t [s] merges t [s] Merging S. Hancock, CERN • Achieving >90% merging efficiency of injected particles • Some ions are already collimated before having been stacked for 15 (20) merging cycles The beta-beam task, EURISOL

  11. collimated Injected/merged decayed Decay ring - Momentum collimation A. Chance et al., Saclay • After 15 (20) merges 50% (70%) of the injected 6He (18Ne) ions are pushed outside the acceptance limits. • Momentum collimation required. • Dispersion region; multi stage collimation system • Space required: placed in “unused” straight section • Collimation power corresponds • to 150 kW average • to MW peak level during the bunch compression process compression process lasts a few hundred milliseconds The beta-beam task, EURISOL

  12. Power loss [W/m] aperture [cm] Decay ring - Decay losses Decay products originating 1) from straight section 2) in arcs 1) are extracted at the first dipole in the arc, sent to dump 2) Arc lattice optimized for absorption of decay products • To accommodate either ion species, the half-aperture has to be very large (~ 8cm for the SC dipoles). • Absorbers take major part of decay losses ion arcs. • About 60 W each • SC dipoles still have to stand <10 W/m. A. Chance et al., Saclay The beta-beam task, EURISOL

  13. Production • Major challenge for 18Ne • Workshop at LLN for production, ionization and bunching this summer • New production method proposed by C. Rubbia! The beta-beam task, EURISOL

  14. Production ring with ionization cooling (C. Rubbia, A.Ferrari, Y.Kadi and V. Vlachoudis) The beta-beam task, EURISOL

  15. Ionization cooling The beta-beam task, EURISOL

  16. Using existing PS and SPS, version 2Space charge limitations at the “right flux” • Space charge tune shift • Note that for LHC the corresponding values are -0.078 and -0.34 • Transverse emittance normalized to PS acceptance at injection for an annual rate of 1018 (anti-) neutrinos The beta-beam task, EURISOL

  17. Ramp time PS Reset time SPS Ramp time SPS Wasted time? The slow cycling time.What can we do? Decay ring SPS PS Production 8 0 Time (s) The beta-beam task, EURISOL

  18. Accumulation at 400 MeV/u T1/2=1.67 s T1/2=17 s T1/2=0.67 s The beta-beam task, EURISOL

  19. Stacking Multiturn injection with electron cooling The beta-beam task, EURISOL

  20. 150Dy • Partly stripped ions: The loss due to stripping smaller than 5% per minute in the decay ring • Possible to produce 1 1011 150Dy atoms/second (1+) with 50 microAmps proton beam with existing technology (TRIUMF) • An annual rate of 1018 decays along one straight section seems as a realistic target value for a design study • Beyond EURISOL DS: Who will do the design? • Is 150Dy the best isotope? The beta-beam task, EURISOL

  21. Long half life – high intensities • At a rate of 1018 neutrinos using the EURISOL beta-beam facility: The beta-beam task, EURISOL

  22. Gamma and decay-ring size, 6He New SPS Civil engineering Magnet R&D The beta-beam task, EURISOL

  23. In 2008 we should know • The EURISOL design study will with the very limited resources available give us: • A feasibility study of the CERN-Frejus baseline • A first idea of the total cost • An idea of how we can go beyond the baseline • Resources and time required for R&D • Focus of the R&D effort • Production, Magnets etc. The beta-beam task, EURISOL

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