tracking and particle-matter interaction studies in the beta-beam decay ring

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E.Wildner , A. Fabich (CERN) Common EURISOL DS - EURONS Town Meeting Helsinki, Finland, 17-19 September 2007. Tracking and particle-matter interaction studies in the beta-beam decay ring. EURISOL Scenario. EURISOL scenario. - PowerPoint PPT Presentation



    Common EURISOL DS - EURONS Town Meeting Helsinki, Finland, 17-19 September 2007 *

  • *EURISOL ScenarioAim: production of (anti-)neutrino beams from the beta decay of radio-active ions circulating in a storage ringSimilar concept to the neutrino factory, but parent particle is a beta-active isotope instead of a muon.

    Accelerate parent ion to relativistic gmaxBoosted neutrino energy spectrum: En2gQForward focusing of neutrinos: 1/g

    EURISOL scenarioIon choice: 6He and 18NeBased on existing technology and machinesStudy of a beta-beam implementation at CERNOnce we have thoroughly studied the EURISOL scenario, we can easily extrapolate to other cases. EURISOL study could serve as a reference.

  • *Possible Beta Beam Complex. Neutrino Source Decay RingIon production ISOL target & Ion sourceProton Driver SPLDecay ringBr = 1500 Tm B = ~6 T C = ~6900 m Lss= ~2500 m 6He: g = 100 18Ne: g = 100SPSAcceleration to medium energy RCS, 1.5 GeVPSAcceleration to final energyPS & SPSBeam to experimentIon acceleration Linac, 0.4 GeVBeam preparation ECR pulsedIon productionAccelerationNeutrino sourceLow-energy partHigh-energy partDetector in the Frejus tunnelExisting!!!8.7 GeV93 GeV

  • *Beta-beam tasks (Eurisol Design Study)From Overview by M. Benedikt, Beta Beam Task Meeting in May 2007

  • *Particle Turnover ~1 MJ beam energy/cycle injected equivalent ion number to be removed~25 W/m average

    Momentum collimation: ~5*1012 6He ions to be collimated per cycleDecay: ~5*1012 6Li ions to be removed per cycle per meter

  • *The Decay Ring OpticsA. Chance et al., CEA SaclayDecay ring: C~7km LSS~2.5 kmOne straight section used for momentum collimation.

  • Particle removal & lossArcsDecay productsStraight sectionMerging increases longitudinal beam sizeMomentum collimationDecay productsPrimarily accumulated and extracted at end with first dipole to external dump.

    Not treated yet: Betatron-Collimation Emergency cases (failure modes)*

  • *Large Aperture Requirements8 cm radius needed for the horizontal plane where the decay products cause daughter beams + 1 cm for the sagitta (no curved magnet)

    4 cm for the vertical plane 6Li 3+18F 9+AbsorberDipoleBeam Pipe

  • *The Large Aperture Dipole, first feasibility study6 TLHC costheta designCourtesy Christine VollingerGood-field requirements only apply to about half the horizontal aperture.

  • *The Decay Products in the arcss (m)Deposited Power (W/m)Courtesy: A. ChancArc, repetitive pattern

  • *Heat Deposition CalculationsNeed to interface beam code and code for tracking particles in matter


    Beam Code: ACCIM (Developed at TRIUMF, many options developed specifically for the decay simulations, responsible Frederick Jones, TRIUMF)

    Particle Tracking in Matter: FLUKA

    "FLUKA: a multi-particle transport code", A. Fasso`, A. Ferrari, J. Ranft, and P.R. Sala, CERN-2005-10 (2005), INFN/TC_05/11, SLAC-R-773 "The physics models of FLUKA: status and recent developments", A. Fasso`, A. Ferrari, S. Roesler, P.R. Sala, G. Battistoni, F. Cerutti, E. Gadioli, M.V. Garzelli, F. Ballarini, A. Ottolenghi, A. Empl and J. Ranft, Computing in High Energy and Nuclear Physics 2003 Conference (CHEP2003), La Jolla, CA, USA, March 24-28, 2003

  • *Accsim, developed at TRIUMF, is a multiparticle tracking and simulation code for synchrotrons and storage rings. Some applications: CERN (S)PS(B), KEK PS, J-PARC, SNS, ... Incorporates simulation tools for injection, orbit manipulations, rf programs, foil, target & collimator interactions, longitudinal and transverse space charge, loss detection and accounting.Interest for Betabeam: to provide a comprehensive model of decay ring operation including injection (orbit bumps, septum, rf bunch merging), space charge effects, and losses (100% !)

    Needed developments for Betabeam:Arbitrary ion species, decay, secondary ions.More powerful and flexible aperture definitions (for absorbers)Tracking of secondary ions off-momentum by >30% (unheard of in conventional fast-tracking codes)Detection of ion losses: exactly where did the ion hit the wall?

    -- a challenge for tracking with the usual element transfer maps

    The beam code ACCSIM

  • *Accsim and FlukaAccsim as event generator for FLUKAIdentify region of interest: sequence of Accsim elements corresponding to the representative arc cell modeled in FLUKA.Tracking 100000 macro-particles representing fully populated ring (9.661013 He or 7.421013 Ne), with decay.Detect and record two types of events:Ions that decayed upstream of the cell and have survived to enter the cell.Ions that decay in the cell.For each event the ion coordinates and reference data are recorded for use as source particles in FLUKA.

  • *Heat Deposition Model, one cellAbsorbersBB (new design)BBQQ (ISR model)QNo Beampipe (angle large)

    Concentric cylinders, copper (coil), iron (yoke) Overlapping Quad to check repeatability of pattern

  • *Coordinate transformationACCSIM/FLUKA and inverse

    We used Mathematica based on the survey options of BeamOptics * to generate FLUKA Particle file

    Useful if ACCSIM could integrate the transformation code xxACCSIMFLUKAyy[cm][cm]* Beam Optics : a program for analytical beam opticsAutin, Bruno; Carli, Christian; D'Amico, Tommaso Eric; Grbner, Oswald; Martini, Michel; Wildner, Elena; CERN-98-06

  • *Particle generation and treatment1. ACCSIM tracks 6Li and 18F particle decaying in the ring up to cell entryStart of cellEnd of cellDecayed in machine with absorbers inserted in ACCSIMDecayed in cell2. ACCSIM gives coordinates and momentum vectors of particles just decayed in cell3. Particles escaping the vacuum pipe are treated by FlukaEscaping

  • *Overall Power DepositionNormalized to a decay rate in cell:He: 5.37 109 decays/sNe: 1.99 109 decays/s 18F6LiCompare to technical limits (10W/m) not exceeding for either ion

  • *Local Power DepositionLimit for quench 4.3mW/cm3 (LHC cable data including margin)Situation fine for 6Li18F: 12 mW/cm3Local power deposition concentrated around the mid plane.

  • *Alternative solutionsOpen Mid Plane Magnet a better solution?Profit of work ongoing at CERNUse this model in simulations Introduce a Beam ScreenCourtesy Erk Jensen, CERN

  • Conclusion and FutureA protocol between the beam code Accsim and the material tracking code (FLUKA) has ben developed for the beta beam studies. ACCSIM to be used for the whole accelerator chain, for decay data production.

    Accsim now to be complemented with the packages made for model creation and for coordinate transformation (Accsim->FLUKA->Accsim)

    First results indicate that the deposited power is exceeding the limits locally, but not globally. Optimisation or another magnet design needed.

    The structure with absorbers would need special arrangements for the impedance induced. A thick liner inside the dipole could be an alternative

    Alternative dipole design with VERY large aperture or open mid-plane (new development, ongoing).

    Apply simulation tools for momentum collimation.