1. Moriond meeting Accelerator based Neutrino beams Mats Lindroos

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

3. Moriond meeting 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

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

5. Moriond meeting CERN to CNGS

6. Moriond meeting The Gran Sasso laboratory

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

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

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

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

11. Moriond meeting Number of particles expected per year: For 1 year of CNGS operation, we expect: (4.8x10 13 protons in SPS, 55% efficiency -- 1997) protons on target4.5 x 10 19 pions / kaons at entrance to decay tunnel 5.8 x 10 19 muons in first / second muon pit 3.6 x 10 18 / 1.1 x 10 17  in 100 m 2 at Gran Sasso 3.5 x 10 12 Upgrade with a factor of 1.5 feasible but requires investment in CERN injector complex

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

13. Moriond meeting CERN underground

14. Moriond meeting CNGS target station

15. Moriond meeting 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 )

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

17. Moriond meeting 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 inner conductor

18. Moriond meeting CNGS Horn test

19. Moriond meeting 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

20. Moriond meeting What is the Super Neutrino Beam? Protons –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

21. Moriond meeting Target stack?

22. Moriond meeting Neutrino factory CERN 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

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

24. Moriond meeting American Study II

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

26. Moriond meeting Pion Capture: Solenoid 20T1.25T

27. Moriond meeting Liquid jet

28. Moriond meeting Jet test at BNL Event #11 25 th April 2001 P-bunch:2.7  10 12 ppb 100 ns t o = ~ 0.45 ms Hg- jet :diameter 1.2 cm jet-velocity 2.5 m/s perp. velocity ~ 5 m/s Picture timing [ms] 0.00 0.75 4.50 13.00 K. Mc Donald, H. Kirk, A. Fabich, J.Lettry Protons

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

30. Moriond meeting Ionization cooling H2H2 rf Liquid H 2 : dE/dx RF restores only P // : E constant Beam sol IN OUT

31. Moriond meeting Cooling experiment

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

33. Moriond meeting Comparison of General Layout SystemCERNFNAL (Study I)BNL (Study II)Japanese System rep rate50 Hz 2.5/5 Hz Proton driver type Linac (SPL)SynchrotronSynchrotron (AGS) Synchrotron p driver energy2.2 GeV16 GeV24 GeV50 GeV Target materialHgCC CollectionHornSolenoid Beam structureBunch-to- bucket Re-bunching Phase rotationrf2 induction linacs 3 induction linacs FFAG Cooling channel88 MHz200 MHz No cooling Acceleration2 RLAs (20/50 GeV) 1 RLA (20 GeV)4 FFAGs (1/3/ 10/20-50 GeV)

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

35. Moriond meeting 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

36. Moriond meeting Low-energy stage Fast acceleration of ions and injection into storage ring Preference for cyclotrons –Known price and technology Acceleration of 16 batches of 1.02x10 12 or 2 10 13 ions/s 6 He(1 + ) from 20 MeV/u to 300 MeV/u Comment: –Bunching in cyclotron? SPL ISOL Target + ECR Storage ring Cyclotrons or FFAG Fast cycling synchrotron PSSPS Decay ring

37. Moriond meeting Storage 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 1.02x10 12 6 He(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 SPL ISOL Target + ECR Storage ring Cyclotrons or FFAG Fast cycling synchrotron PSSPS Decay ring

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

39. Moriond meeting PS Accumulation of 16 bunches at 300 MeV/u each consisting of 2.5x10 12 6 He(2+) ions Acceleration to  =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 SPL ISOL Target + ECR Storage ring Cyclotrons or FFAG Fast cycling synchrotron PS SPS Decay ring

40. Moriond meeting SPS Acceleration of 8 bunches of 6 He(2 + ) to  =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 Storage ring Cyclotrons or FFAG Fast cycling synchrotron PS SPS Decay ring

41. Moriond meeting 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 Storage ring Cyclotrons or FFAG Fast cycling synchrotron PSSPS Decay ring

42. Moriond meeting Intensities: 18 Ne From ECR source: 0.8x10 11 ions per second Storage ring: 4.1 x10 10 ions per bunch Fast cycling synch:4.1 x10 10 ion per bunch PS after acceleration: 5.2 x10 11 ions per batch SPS after acceleration:4.9 x10 11 ions per batch Decay ring: 9.1x10 12 ions in four 10 ns long bunch –Only  -decay losses accounted for, efficiency <50%

43. Moriond meeting Intensities: 6 He From ECR source: 2.0x10 13 ions per second Storage ring: 1.0 x10 12 ions per bunch Fast cycling synch:1.0 x10 12 ion per bunch PS after acceleration: 1.0 x10 13 ions per batch SPS after acceleration:0.9x10 13 ions per batch Decay ring: 2.0x10 14 ions in four 10 ns long bunch –Only  -decay losses accounted for, efficiency <50%

44. Moriond meeting 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

45. Moriond meeting Higher energy in the decay ring? LHC top rigidity (23270 Tm): – 6 He has a  =2488.08 – 18 Ne has a  = 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

46. Moriond meeting 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?

47. Moriond meeting 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

48. Moriond meeting What I can see in the crystal ball 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 As any Harry Potter reader knows that the art of crystal ball viewing is both very difficult and often prone to errors!

49. Moriond meeting 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!