Betabeams M Benedikt A Fabich M Lindroos CERN
Beta-beams M. Benedikt, A. Fabich, M. Lindroos CERN AB/ATB on behalf of the Beta-beam Study Group http: //cern. ch/beta-beam FNAL Steering Group: To develop a strategic roadmap for the accelerator-based HEP program
Outline n Beta-beam concept n EURISOL DS scenario n n n Baseline layout Accelerator complex Limitation studies Decay ring Summary
Beta-beam principle Aim: production of (anti-)neutrino beams from the beta decay of radio-active ions circulating in a storage ring n Similar concept to the neutrino factory, but parent particle is a beta-active isotope instead of a muon. n. Ions move almost at the speed of light Neutrino detector n Accelerate parent ion to relativistic gmax n n Boosted neutrino energy spectrum: E n 2 g. Q Forward focusing of neutrinos: 1/g EURISOL scenario n n Ion choice: 6 He and 18 Ne Based on existing technology and machines Study of a beta-beam implementation at CERN Once we have thoroughly studied the EURISOL scenario, we can “easily” extrapolate to other cases. EURISOL study could serve as a reference.
Acceleration scenario Cycle optimized for neutrino rate towards the detector for physics reach Bunch 20 th total 15 th 10 th 5 th 1 st M 1. 1 Final choice on baseline design M 2. 1 RCS in/output parameters M 3. 1 PS/SPS in/output parameters M 4. 1 Decay ring main parameters Documentation: n Parameters and intensity values n Note Version 1 2005 -01 n Note Version 2 2005 -03 n Parameter database n Note 2006 -07 RCS optics M 2. 2 RCS First order optics design Documentation: n Preliminary RCS design 2006 -05 n RCS RF characteristics 2006 -09
Limitations by decay losses P. Spiller et al. , GSI n Decay losses cause degradation of the vacuum due to desorption from the vacuum chamber n Heat deposition and activation by beam losses limits the machine operation and lifetime. M 3. 2 Identification of limitation Documentation: n Beta-beam decay losses 2005 -05 n Dynamic vacuum 2006 -07
Space charge related issues Beam growth due to intra-beam scattering Simulation for 18 Ne using MAD n at inj. RCS PS SPS DECAY tlong [s] 2 6 39 2189 thor [s] -595 -360 -63148 -1013 tver [s] -302 -341 -9145 -277855 Growth time t should be larger than acceleration time taccel. [s] 0. 05 1. 9 0. 8 ~100
M 4. 2 Decay ring first order optics design Documentation: n First design for the optics of the decay ring of the beta-beams 2006 -05 n Loss management 2007 -0013 p-collimation deca injection merging y los Particle turnover n ~1 MJ beam energy/cycle injected ses equivalent ion number to be removed ~25 W/m average Requires a system of absorbers and collimators to remove the beam of parent and daughter ions. Optical functions (m) A. Chance et al. , CEA Saclay Decay ring primary collimator s (m) n. LHC project report 773 bb
Longitudinal penetration in coil Superconducting Dipole Design FLUKA simulation model E. Wildner et al. , CERN Power deposited in dipole Coil No absorber Abs Coil Carbon Abs Coil Stainless Steel
Summary EURISOL DS n No deviations from the initial planning. n Beta-beam accelerator complex is a high technical challenge due to ion intensities without precedent. n n Activation and heat deposition Space charge n So far ion acceleration for a EURISOL beta-beam scenario looks technically feasible. n Short-fall of 18 Ne production not yet resolved. n n n Collaboration with EURISOL production task 3. Cross-sections for direct production currently measured at LLN. Alternative production scenarios might be investigated.
Ways forward: Guideline to n-beam scenarios based on radio-active ions • Low-energy beta-beam: relativistic g < 20 • Medium energy beta-beam: g ~ 100 • High energy beta-beam: g >350 • Monochromatic neutrino-beam • High-Q value beta-beam: g ~ 100 – Physics case: neutrino scattering – EURISOL DS – Today the only detailed study of a beta-beam accelerator complex – Take advantage of increased interaction cross-section of neutrinos – Take advantage of electron-capture process Accelerator physicists together with neutrino physicists defined the accelerator case of g=100/100 to be studied first (EURISOL DS).
A new approach for the production and high-Q Beam cooling with ionisation losses – C. Rubbia, A Ferrari, Y. Kadi and V. Vlachoudis in NIM A 568 (2006) 475– 487 “Many other applications in a number of different fields may also take profit of intense beams of radioactive ions. ” 7 Li 6 Li 7 Li(d, p)8 Li 6 Li(3 He, n)8 B Missed opportunities See also: Development of FFAG accelerators and their applications for intense secondary particle production, Y. Mori, NIM A 562(2006)591
(Higher) Gamma and decay-ring size, 6 He Gamma Rigidity [Tm] Ring length T=5 T f=0. 36 Dipole Field rho=300 m Length=6885 m 100 150 200 350 500 938 1404 1867 3277 4678 4916 6421 7917 12474 17000 3. 1 4. 7 6. 2 10. 9 15. 6 New SPS Civil engineering Magnet R&D
Site constraints “Stretched Tevatron“ aimed at Soudan B = 3335 Tm R = 1000 m (75% 4. 4 T dipoles) LSS= ~3500 Total circumference: approximately 2 x Tevatron 320 m elevation @ 58 mrad 26% of decays in SS
Next step in Europe for neutrino oscillation physics • We have some questions to answer: – Considering safety, cost and feasibility; can we agree on a set of baselines for the proposed future neutrino oscillation facilities? – How do we compare the different facilities? – Can we propose a road map for the future of this subject? • Attempt to address some of these issues in a new European design study proposal for a future neutrino oscillation facility – Euron DS
Summary • EURISOL DS beta-beam (g=100) is Study I for beta-beams • The physics reach for the EURISOL DS scenario is competitive for 13>1 O. • If we want to improve the physics reach what are the ways forward • Staging of the facility makes a lot of sense if it is possible to do experiments with anti-neutrinos first • – This first study had limited ambitions – Usefulness depends on the short/mid-term findings by other neutrino search facilities. – – – Higher g ( > 100) Higher intenisty High Q value isotopes – Easy to produce 6 He and 8 Li with small and compact production unit e. g. low energy but high power proton/deuterium driver A Study II for beta-beams in the US! – – – The proposed Euron DS but it will only give us very limited resources for R&D, mostly review work. It can run in parallel to a study in the US (link through IDS mechanism) FNAL would be an excellent site for a beta-beam considering e. g. ramp time of existing accelerators and space on the site for a large ring The European beta-beam team is willing to help giving a possible US beta-study a “flying start” Explore link to ANL at an early stage to get US RNB experts involved, will represent major time gain Links to other projects should be investigated e. g. new dipoles for upgrade of LHC injection region
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