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DAE  ALUS

DAE  ALUS. High Current H 2 + Cyclotrons for Neutrino Physics: The IsoDAR and DAE d ALUS Projects. Jose Alonso, Luciano Calabretta MIT INFN-LNS For the DAE d ALUS Collaboration. Outline. Neutrino oscillations and CP violation are very hot topics! Background

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DAE  ALUS

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  1. DAEALUS High Current H2+ Cyclotrons for Neutrino Physics: The IsoDAR and DAEdALUS Projects Jose Alonso, Luciano Calabretta MIT INFN-LNS For the DAEdALUS Collaboration

  2. Outline • Neutrino oscillations and CP violation are very hot topics! • Background • Decay-at-rest (DAR) program • The DAEdALUS experiment • Requirements • The IsoDAR experiment • Requirements • Siting options • Cyclotron designs and calculations • Luciano Calabretta • Status and Developments TRIUMF, Sept 13, 2012

  3. Background… • Neutrino representations in 2 sets of eigenstates: • Flavor (ne, nm, nt) related to production reaction • Mass (n1, n2, n3) • Coupling between determined by “mixing angles” • Example (2-state system): Flavor states TRIUMF, Sept 13, 2012

  4. Background… • 3-state system coupling is a “simple” extrapolation Mass eigenstates Flavor eigenstates TRIUMF, Sept 13, 2012

  5. Background… • Uij are sin/cos function of mixing angles • All now measured • q13 latest to be measured • Some elements also contain CP violation terms eid TRIUMF, Sept 13, 2012

  6. Oscillations (for 2-state system) Posc = sin22q sin2(1.27Dm2L/E) sin22q = mixing strength P = oscillation probability Dm2 = mass difference (squared) for mass eigenstates (eV2) L = baseline length (km) E = neutrino energy (GeV) Start with a pure ne beam TRIUMF, Sept 13, 2012

  7. Oscillations (for 2-state system) Posc = sin22q sin2(1.27Dm2L/E) sin22q = mixing strength P = oscillation probability Dm2 = mass difference (squared) for mass eigenstates (eV2) L = baseline length (km) E = neutrino energy (GeV) For Dm2 ~ 2.4 x 10-3, eV2 E ~ 1 GeV, DL ~ 1000 km (optimized Long Baseline conditions) TRIUMF, Sept 13, 2012

  8. Oscillations (for 3-state system) TRIUMF, Sept 13, 2012

  9.  CP violating terms terms depending on mass splittings terms depending on mixing angles Oscillations (for 3-state system) Sign difference between n and n TRIUMF, Sept 13, 2012

  10.  CP violating terms terms depending on mass splittings terms depending on mixing angles Oscillations (for 3-state system) Sign difference between n and n TRIUMF, Sept 13, 2012

  11. CP Violation Option 1: Long-baseline configuration (~1000 km, ~1 GeV neutrinos) Changing between nm and nm (- or +) Option 2: Decay-at-rest configuration (1-20 km, ~30 MeV neutrinos) Changing baseline length (changing D) ------ NOTE: HUGE benefit from combining both measurements in same detector! TRIUMF, Sept 13, 2012

  12. Decay-At-Rest TRIUMF, Sept 13, 2012

  13. DAR Detection • Look for appearance of ne • Inverse beta decay (IBD) in detector with lots of free protons • Water Cherenkov or Liquid Scintillator • Unique signature: Delayed coincidence • Huge benefit in discrimination against background ~ 2 ms TRIUMF, Sept 13, 2012

  14. TRIUMF, Sept 13, 2012

  15. TRIUMF, Sept 13, 2012

  16. Six MW Target Concept r0 = 20 cm z0 = 8 m weight = 55 tons Copper (hollow) Graphite Chris Tschalaer, MIT 2011 TRIUMF, Sept 13, 2012

  17. Accelerator Requirements • Beam on target: ~800 MeV protons • Beam power*: • 1.5 km site: 0.8 MW average • 8 km site: 1.6 MW average • 20 km site: 4.8 MW average • Accelerator duty factor ~ 20% • Instantaneous power requirement is x5 average pwr ___________ *Based on matching data rates in proposed 200 kTon Water Cherenkov counter, and LBNE beamline from FNAL to Homestake TRIUMF, Sept 13, 2012

  18. Accelerator requirementsin perspective AVERAGE power PEAK power TRIUMF, Sept 13, 2012

  19. Cyclotrons: Viable technology? • PSI is current world power leader in this energy range ~ 1 MW average, 590 MeV protons • Extrapolation to higher power? _________ • Problems: • Capture of more ions… space-charge at injection • Clean extraction… max loss 200 W (~10-4) TRIUMF, Sept 13, 2012

  20. Proposed Solution: H2+ ions • Two protons for every ion (1 emA = 2 pmA) • Perveance of 5 emA H2+ at 35 keV/amusame as 2 emA of 30 keV protons • Axial injection of 2 emA protons at 30 keV is well within state of the art • Extract with stripping foil • Clean turn separation is not needed, only high-acceptance extraction channel TRIUMF, Sept 13, 2012

  21. Concept (Luciano Calabretta)INFN-Catania TRIUMF, Sept 13, 2012

  22. Development Strategy • With highly-complex projects: • Develop phased approach • Design phases such that good physics can be done with each TRIUMF, Sept 13, 2012

  23. Development Strategy • With highly-complex projects: • Develop phased approach • Design phases such that good physics can be done with each • In our case… Injector cyclotron can in itself be a “barn-burning” neutrino source • The IsoDAR Project • 10 pmA (CW) at 60 MeV/amu = 600 kW! TRIUMF, Sept 13, 2012

  24. IsoDAR (Isotope Decay At Rest) • Proton beam into neutron-producing target • Secondary neutrons into ~50 kg pure 7Li blanket • 8Li decay produces ne, high beta endpoint energy • Good for discriminating background • As with DAEdALUS, use IBD in liquid scintillator • Good spatial, energy resolution GOAL: STERILE NEUTRINO SEARCH TRIUMF, Sept 13, 2012

  25. Sterile Neutrino • Anomalies in n, n behaviors • LSND, MiniBooNE • Reactor flux anomaly • Possible explanation: • New neutrinos that do notinteract via weak force butstill can oscillate with otherneutrino states • Most likely Dm2 ~ 1 eV2 • DL ~ few meters! TRIUMF, Sept 13, 2012

  26. Oscillations can be seen within detector! TRIUMF, Sept 13, 2012

  27. SNO+ also encouraging IsoDAR TRIUMF, Sept 13, 2012

  28. Engineering Challenges for DIC • Deliver components through narrow passage-ways or down shafts • 4-meter diameter coil will NOT fit! • KamLAND drive-in access, drift height < 4 meters • Creighton mine shaft (SNO+) is ~3.8 x 1.5 m • Pole pieces too heavy for hoist • Creighton hoist has 12 ton limit • Power and cooling • Neutron shielding TRIUMF, Sept 13, 2012

  29. DAEALUS Cyclotron Design and Simulation Studies Luciano Calabretta INFN-LNS For the DAEdALUS Collaboration

  30. Injector Cyclotron • 60 MeV/amu, 5 emA H2+ • Normal conducting coils ~ 4 meter coil diameter • Axial injection (spiral inflector) • Electrostatic extraction channel Coil Electrostatic deflectors arXiv: 1207.4895 Extractiontrajectory TRIUMF, Sept 13, 2012

  31. Courtesy of R. Doelling Injection energy and acceleration voltage are higher vs. C30/TR-30 60 MeV/n after 100 turn vs. 150, or 12 msec vs. 8.1 msec Main parameters are extrapolated from existing commercial compact cyclotron: C30 and TR-30

  32. Beam size vs. turns number for different beam current 1 MeV/n 61.7 MeV/n Particle’s distribution at last turn See, Jianjun Yang presentationat ECPM 2012 [m]

  33. Beam emittance 6.4 pmm.mrad, off center + 3mm at orbit of 1 MeV/n

  34. nr nr

  35. Powerlost on the septum of E.D. 120 W @ 600 kW! See, Jianjun Yang presentationat ECPM 2012

  36. DAEdALUSSuperconducting Ring Cyclotron • H2+ injected in the ring cyclotron at 60MeV/n • Last closed orbit at 800MeV • Isochronous field. Average field ≈2T • Simulation done with OPERA3D: • Design the structure • Define materials • Design coils • Define mesh • Solve through Tosca (FEM) • Elaborate and visualize results with Post-Processor • Optimization process • To accelerate H2+ the magnetic field is 2 times higher than for protons  superconducting coils • Losses have to be limited to a few hundred watts in total

  37. DAEdALUSSuperconducting Ring Cyclotron 8 SUPERCONDUCTING sector magnets: view of1/16 of the cyclotron: median plane is above the upper hill Pole gap= 80mm Sector Weight <450tons Halfheight 2.8m Outer radius ≈7m Outer Yoke hill Inner Yoke Pole

  38. RIKEN SRC sector DAEdALUS –SRC COILS On the coil surface Bmodmax≈6T RIKEN The longeststraightarms of the coils will be conncted with a platepassingbetween the upper and lowerhill. Thiswill be necessary to cancel the expansionmagneticforceswhichtend to make the coil round

  39. DAEdALUS –SRC COILS Front view Top view The different cross section is needed to guarantee enough space in the center region for the RF Cavities installation (and maybe is not enough!) Current density 3400A/cm2, Area 30x24cm2 or 15x48cm2 The winding of the cable could be a blocking point for cooling reasons, Hugeforcesdevelopped

  40. DAEdALUS –SRC OPTIMIZATION RESULTS ±0.5% between isochronous and calculated We need 10-4 All dangerous resonances are crossed quickly Walkingshaw resonance NOT crossed at the end of acceleration

  41. DAEdALUS –SRC LAYOUT Bmax on the patch on the medianplan 6.05T Bmin on a patch on the medianplan -2.5T 1 ElectrostaticDeflector + 4 Magneticchannels for the injection

  42. DAEdALUS –SRC CAVITIES Twosolutionsanalyzed Double gap cavity multi sistem cavity like SC Compact Cyc Single gap cavity like 590MeV PSI cyc With the courtesy of L. Piazza INFN-LNL

  43. Space chargeeffectshavenegligibleeffectsduringacceleration in the ring cyclotron Vertical beam size along the acceleration in the radial range from 4 to 4.9 m, snapshot at 0° azimuth. The left figure has no charge space effects, 0 mA. The right figure is evaluated with a 5 mA beam H2+ current Simulation made by J. Yang and A. Adelman, using OPAL code

  44. Histogram of 5 mA H2+ beamat the stripper foil position, simulation include spacechargeeffects (OPAL code) DE/E% phase (deg) The radial size of the beam dependmainlyby the energygain per turn Z (mm) R (mm)

  45. Effect due crossing Walkinshaw resonance

  46. Steering /focusing Magnetic Channel Extraction trajectories energy spread< ±0.6% 2° Stripper Stripper foils 2°proton beam TRIUMF, Sept 13, 2012

  47. H2+ beam If B=0.4 T Re=4.5 mm Stripper foil emerging protons electrons catcher Stripper foil: 5 MW beam @ 800 MeV Xing a stripper foil 1 mg/cm2 thick release  45 W due to nuclear interaction! The electrons removed by the strippers have a full power of 5 MW*Me/MH2=5/(2*1826)=1370 W ! Electrons are the main source of stripper damage But, electrons can be stopped before strike the stripper Stripper Thickness can be also thinner, because: H- =(p+e+e)  p, e, e is a two steps process (p+e+e) H + e  p, e, e H2+ =(p+p+e)p, p, e is a single step process, lower probability for H2+H + p The neutral H can be removed by an additional stripper foil, 10 cm later

  48. injection extraction [cm] yoke

  49. BEAM LOSSES

  50. 3 major blocking points in the design the variable cross-section that could cause complications on the LHe cooling system Huge residual radial FORCE that pushed outward the coil Not enough SPACE left between two contiguous sectors to install RF cavities PSI like

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