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Accelerator based Neutrino beams

Accelerator based Neutrino beams. Mats Lindroos. Outline. Existing facilities CNGS The super beam The neutrino factory The beta beam Conclusions. Acknowledgments. CNGS Konrad Elsener, CERN The Superbeam Helmut Haseroth, Konrad Elsener, Tsuyoshi Nakaya The Neutrino Factory

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Accelerator based Neutrino beams

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  1. Accelerator based Neutrino beams Mats Lindroos Moriond meeting

  2. Outline • Existing facilities • CNGS • The super beam • The neutrino factory • The beta beam • Conclusions Moriond meeting

  3. Acknowledgments • CNGS • Konrad Elsener, CERN • The Superbeam • Helmut Haseroth, Konrad Elsener, Tsuyoshi Nakaya • The Neutrino Factory • The nufact study group • The beta beam • The beta beam working group Moriond meeting

  4. Beta beam CNGS In Dec. 1999, CERN council approved the CNGS project: build an intense nm beam at CERN-SPS search for ntappearance at Gran Sasso laboratory (730 km from CERN) “long base-line”nm--ntoscillation experiment note: K2K (Japan) running; NuMI/MINOS (US) under construction Moriond meeting

  5. CERN to CNGS Moriond meeting

  6. The Gran Sasso laboratory Moriond meeting

  7. p + C (interactions) p+, K+ (decay in flight) m+ + nm The CERN part Polarity change foreseen! …but the intensity will go down and the contamination goes up Moriond meeting

  8. p / K profile at entrance to decay tunnel Moriond meeting

  9. CNGS muon beam profiles first muon pit second muon pit Moriond meeting

  10. Radial distribution of thenm- beam at Gran Sasso note: 1 mm -> 1 km Moriond meeting

  11. Number of particles expected per year: For 1 year of CNGS operation, we expect: (4.8x1013 protons in SPS, 55% efficiency -- 1997) protons on target4.5 x 1019 pions / kaons at entrance to decay tunnel 5.8 x 1019 muons in first / second muon pit 3.6 x 1018 / 1.1 x 1017 nmin 100 m2 at Gran Sasso 3.5 x 1012 Upgrade with a factor of 1.5 feasible but requires investment in CERN injector complex Moriond meeting

  12. Unwanted neutrino species Relative to the main nm component: ne / nm= 0.8 %    anti-nm / nm= 2.1 %    anti-ne / nm = 0.07 %   Moriond meeting

  13. CERN underground Moriond meeting

  14. CNGS target station Moriond meeting

  15. CNGS target -> 10 cm long graphite rods, Ø=5mm and/or 4mm proton beam Note: - target rods interspaced to “let the pions out” - target is helium cooled (remove heat deposited by the particles) Moriond meeting

  16. CNGS focusing devices “Magnetic Horn” (S. v.der Meer, CERN) length: 6.5 m diameter: 70 cm weight: 1500 kg Pulsed devices: 150kA / 180 kA, 1 ms water-cooled: distributed nozzles Moriond meeting

  17. inner conductor Principle of focusing with a Magnetic Horn Magnetic volume given by “one turn” at high current:  specially shaped inner conductor - end plates  cylindrical outer conductor Moriond meeting

  18. CNGS Horn test Moriond meeting

  19. CNGS decay tube + hadron stop - dimensions of decay tube: 2.45 m diameter steel tubes, 6 m long pieces, 1 km total  welded together in-situ  vacuum: ~1 mbar  tube embedded in concrete - hadron stop: 3.2 m graphite  15 m iron blocks  upstream end: water cooled Moriond meeting

  20. Protons Protons Protons Protons Protons What is the Super Neutrino Beam? • No Clear definition, but it is a very intense neutrino beam produced by a high power (>1MW ) accelerator. • A conventional method. • Still technically challenging due to the high power and the high radiation environment, but not impossible. • Multiple targets Moriond meeting

  21. Target stack? Moriond meeting

  22. Neutrino factoryCERN • Superconducting proton linac as driver • Proton bunch train not longer than decay ring • Bunch to bucket philosophy • Longitudinal cooling using bunch rotation • Transversal cooling using ionization cooling • Recirculating linear accelerators • Decay ring Moriond meeting

  23. Neutrino factoryJapan 3 GeV and 50 GeV rings are part of JAERI-KEK Joint Project Moriond meeting

  24. American Study II Moriond meeting

  25. Current of 300 kA p To decay channel Protons B = 0 Hg target B1/R Gilardoni Target and pion captureliquid jet+Horn Moriond meeting

  26. Pion Capture: Solenoid 20T 1.25T Moriond meeting

  27. Liquid jet Moriond meeting

  28. Event #1125th April 2001 K. Mc Donald, H. Kirk, A. Fabich, J.Lettry Protons Picture timing [ms] 0.00 0.75 4.50 13.00 P-bunch: 2.71012 ppb 100 ns to = ~ 0.45 ms Hg- jet : diameter 1.2 cm jet-velocity 2.5 m/s perp. velocity ~ 5 m/s Jet test at BNL Moriond meeting

  29. Targetry Many difficulties: enormous power density lifetime problems pion capture Stationary target: Replace target between bunches: Liquid mercury jet or rotating solid target Proposed rotating tantalum target ring Sievers Densham Moriond meeting

  30. Ionization cooling IN Liquid H2:dE/dx sol H2 rf Beam sol RF restoresonly P//: E constant Moriond meeting OUT

  31. Cooling experiment Moriond meeting

  32. Cooling - rings Main advantages: shorter longitudinal cooling Balbekov Palmer Moriond meeting

  33. System CERN FNAL (Study I) BNL (Study II) Japanese System rep rate 50 Hz 2.5/5 Hz Proton driver type Linac (SPL) Synchrotron Synchrotron (AGS) Synchrotron p driver energy 2.2 GeV 16 GeV 24 GeV 50 GeV Target material Hg C C Collection Horn Solenoid Solenoid Beam structure Bunch-to-bucket Re-bunching Re-bunching Phase rotation rf 2 induction linacs 3 induction linacs FFAG Cooling channel 88 MHz 200 MHz 200 MHz No cooling Acceleration 2 RLAs (20/50 GeV) 2 RLAs (20/50 GeV) 1 RLA (20 GeV) 4 FFAGs (1/3/ 10/20-50 GeV) Comparison of General Layout Moriond meeting

  34. Decay ring Brho = 1500 Tm B = 5 T Lss = 2500 m SPL Decay Ring ISOL target & Ion source Cyclotrons Storage ring and fast cycling synchrotron b-beam baseline scenario SPS PS Moriond meeting

  35. Objectives for CERN study • Present a coherent and “realistic” scenario for acceleration of radioactive ions: • Use known technology (or reasonable extrapolations of known technology) • Use innovations to increase the performance • Re-use a maximum of the existing CERN accelerators • Use the production limit for ions of interest as starting point Moriond meeting

  36. SPL ISOL Target + ECR Cyclotrons or FFAG Storage ring Fast cycling synchrotron PS SPS Decay ring Low-energy stage • Fast acceleration of ions and injection into storage ring • Preference for cyclotrons • Known price and technology • Acceleration of 16 batches of 1.02x1012 or 2 1013 ions/s 6He(1+) from 20 MeV/u to 300 MeV/u • Comment: • Bunching in cyclotron? Moriond meeting

  37. Storage ring SPL ISOL Target + ECR Cyclotrons or FFAG Storage ring Fast cycling synchrotron PS SPS Decay ring • Charge exchange injection into storage ring • Technology developed and in use at the Celsius ring in Uppsala • Accumulation, bunching (h=1) and injection into PS of 1.02x10126He(2+) ions • Question marks: • High radioactive activation of ring • Efficiency and maximum acceptable time for charge exchange injection • Electron cooling or transverse feedback system to counteract beam blow-up Moriond meeting

  38. Overview: Accumulation • Sequential filling of 16 buckets in the PS from the storage ring Moriond meeting

  39. PS SPL ISOL Target + ECR Cyclotrons or FFAG Storage ring Fast cycling synchrotron PS SPS Decay ring • Accumulation of 16 bunches at 300 MeV/u each consisting of 2.5x10126He(2+) ions • Acceleration to g=9.2, merging to 8 bunches and injection into the SPS • Question marks: • Very high radioactive activation of ring • Space charge bottleneck at SPS injection will require a transverse emittance blow-up Moriond meeting

  40. SPS • Acceleration of 8 bunches of 6He(2+) to g=150 • Acceleration to near transition with a new 40 MHz RF system • Transfer of particles to the existing 200 MHz RF system • Acceleration to top energy with the 200 MHz RF system • Ejection in batches of four to the decay ring SPL ISOL Target + ECR Cyclotrons or FFAG Storage ring Fast cycling synchrotron PS SPS Decay ring Moriond meeting

  41. Decay ring • Injection and accumulation will be described in talk on Thursday • Major challenge to construct radiation hard and high field magnets SPL ISOL Target + ECR Cyclotrons or FFAG Storage ring Fast cycling synchrotron PS SPS Decay ring Moriond meeting

  42. Intensities: 18Ne • From ECR source: 0.8x1011 ions per second • Storage ring: 4.1 x1010 ions per bunch • Fast cycling synch: 4.1 x1010 ion per bunch • PS after acceleration: 5.2 x1011 ions per batch • SPS after acceleration: 4.9 x1011 ions per batch • Decay ring: 9.1x1012 ions in four 10 ns long bunch • Only b-decay losses accounted for, efficiency <50% Moriond meeting

  43. Intensities: 6He • From ECR source: 2.0x1013 ions per second • Storage ring: 1.0 x1012 ions per bunch • Fast cycling synch: 1.0 x1012 ion per bunch • PS after acceleration: 1.0 x1013 ions per batch • SPS after acceleration: 0.9x1013 ions per batch • Decay ring: 2.0x1014 ions in four 10 ns long bunch • Only b-decay losses accounted for, efficiency <50% Moriond meeting

  44. Result of CERN study • A baseline scenario for the beta-beam at CERN exists • While, possible solutions have been proposed for all identified bottlenecks we still have problems to overcome and… • …it is certainly possible to make major improvements! • Which could result in higher intensity in the decay ring! • First results are so encouraging that the beta-beam option should be fully explored • Investigate sites at other existing accelerator laboratories • Study a “Green field” scenario Moriond meeting

  45. Higher energy in the decay ring? • LHC top rigidity (23270 Tm): • 6He has a g=2488.08 • 18Ne has a g= 4158.19 • With a “futuristic” radiation hard superconducting dipole design for the decay ring with a field of 5 Tesla the radius of the arcs will be r=4654 m! • Bigger than LHC arcs! • Lower intensities as LHC only can handle transversally small bunches Moriond meeting

  46. Neutron beams? • As for a neutrino beam and neutron beam can be created if a beta-delayed neutron emitter is stored in the decay ring • High energy • Physics case? • Low energy • Medical use – neutron therapy • Waste transmutation at neutron resonances • Intensity? Moriond meeting

  47. Comments • The super beam can be available soon (when the necessary high power drivers are completed) • The beta-beam is largely based on existing technology but requires costly civil engineering for the decay ring • Moderate extrapolations on target technology • Strong synergies with projects in nuclear physics • EURISOL • GSI upgrade • SPIRAL-2 • SPES in Legnaro • Ion programme in LHC and low energy ion (accelerator and) storage rings in Europe • The R&D for a full scale muon based neutrino factory is fascinating but very challenging • Target issues still requires major R&D • Ionization cooling has to be experimentally tested Moriond meeting

  48. What I can see in the crystal ball As any Harry Potter reader knows that the art of crystal ball viewing is both very difficult and often prone to errors! • High power proton drivers become available • Next generation ISOL RNB facilities • Super beams • Low energy electron neutrino beams available • Physics case? • The beta-beam is taken to higher energies • Muon based neutrino factory starts delivering beam Moriond meeting

  49. Conclusion • Beta-beam at CERN: • Low energy part will benefit nuclear physics • Acceleration to high energy is likely to benefit heavy ion programme • LHC beam brightness? • Find a way of benefiting ion programme in LHC with our decay ring and our luck might be made! • Having said that… • GSI is world leading on high energy ions • Should open new possibilities at GSI for ions • Having said that… • Italy is the only European country that seems willing to invest in high energy physics inclduing neutrinos and underground detectors • Low energy neutrino beams? • Having said that… • GANIL is one of the centers for accelerated radioactive ions • Low energy neutrino beams? • I hope I have set out a promising future for the research in to different aspects of the beta-beam! Moriond meeting

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