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Beta Beams and Neutrino factories Selected topics

Beta Beams and Neutrino factories Selected topics. Elena Wildner Acknowledgements: J.Pozimski S.Berg C. Rogers A Fabich M.Lindroos and many others. Neutrinofactory, superbeam,  beam. Neutrinofactory :.  + → e + ν e ν  and  - → e - ν e ν .

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Beta Beams and Neutrino factories Selected topics

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  1. Beta Beams and Neutrino factoriesSelected topics Elena Wildner Acknowledgements: J.Pozimski S.Berg C. Rogers A Fabich M.Lindroos and many others

  2. Neutrinofactory, superbeam,  beam Neutrinofactory : +→e+νeν and -→e-νeν Defined energy given by muon, 12 channels to observe, magnetized detector required to distinguish sign of particles, 3500 km and 7500 km baselines. Superbeam : Broad energy spectrum upper limit defined by proton energy, pion decay, search for νdisappearence or ν, νe appearence, large volume detector (water Cerenkov), typical baselines 100 - 1000 km b-beam : Defined energy spectrum defined by , pure νe or νe beams, 6 channels to observe, no magnetisation required - large volume detector (water Cerenkov), typical baselines 100 - 700 km Nufact School 2009

  3. History beta beams Beta-beam proposal by PieroZucchelli A novel concept for a neutrino factory: the beta-beam, Phys. Let. B, 532 (2002) 166-172. FP6 "Structuring the European Research Area" programme (CARE, contract number RII3-CT-2003-506395) 4 year study finishing July 2009 FP7 “Design Studies” (Research Infrastructures) EUROnu (Grant agreement no.: 212372) 2008-2012 Elena Wildner, June -09 Nufact School 2009 3

  4. Beta Beams, recall Aim: production of (anti-)neutrino beams from the beta decay of radio-active ions circulating in a storage ring (race track). Similar concept to the neutrino factory, but parent particle is a beta-active isotope instead of a muon. Both neutrinos and antineutrinos are needed Beta-decay at rest n-spectrum well known from electron spectrum Reaction energy Q typically of a few MeV (neutrino energy) Only electron (anti-)neutrinos Accelerated parent ion to relativistic gmax Boosted neutrino energy spectrum: En  2gQ Forward focusing of neutrinos:   1/g Beta-beam n n 6He boost g=100 Elena Wildner, June -09 Nufact School 2009 4

  5. t1/2 at rest (ground state) 1ms – 1s 1 – 60 s NuBase Choice of radioactive ion species 6He and 18Ne • Beta-active isotopes • Production rates • Life time • Dangerous rest products • Reactivity (Noble gases are good) • Reasonable lifetime at rest • If too short: decay during acceleration • If too long: low neutrino production • Optimum life time given by acceleration scenario and neutrino rate optimization • In the order of a second • Low Z preferred • Minimize ratio of accelerated mass/charges per neutrino produced • One ion produces one neutrino. • Reduce space charge problems 8Li and 8B EURISOL DS Nufact School 2009

  6. Elena Wildner Guideline to n-beam scenarios based on radio-active ions • Low-energy beta-beam: relativisticg < 20 • Physics case: neutrino scattering • Medium energy beta-beam: g ~ 100 • EURISOL DS • Today the only detailed study of a beta-beam accelerator complex • High energy beta-beam: g >350 • Take advantage of increased interaction cross-section of neutrinos • Monochromatic neutrino-beam • Take advantage of electron-capture process • High-Q value beta-beam:g ~ 100 Accelerator physicists together with neutrino physicists defined the accelerator case of g=100/100 to be studied first (EURISOL DS). Nufact School 2009

  7. Some scaling useful for Accelerator Physicists • Accelerators can accelerate ions up to Z/A × the proton energy. • L ~ En / Dm2 ~ gQ , Flux ~ L−2 => Flux ~ Q −2 • Cross section ~ En ~ g Q • Merit factor for an experiment at the atmospheric oscillation maximum: M= g /Q • Decay ring length scales ~ g (ion lifetime) Nufact School 2009

  8. Challenges for beta beams • Ion production • Radiation issues and energy deposition • Vacuum • Collimation • Decay ring bunch structure for detector background • Space Charge • Cycle optimization • … Nufact School 2009

  9. To set up a beta beam facility Decay ring Br = 1500 Tm B = ~6 T C = ~6900 m Lss= ~2500 m 6He: g = 100 18Ne: g = 100 Aimed rates: He 2.9 1018 ( 2.0 1013/s after target) Ne 1.1 1018 ( 2.0 1013/s after target) 93 GeV 0.4 GeV 8.7 GeV 1.7 GeV Nufact School 2009 9

  10. ISOL, 6He/18Ne and 8B/8Li 6He • Tests of BeO at 3 kW at ISOLDE, analysis ongoing, encourageing! • 2 GeV on water-cooled W 18Ne • To be studied (Frame-work, Priority?) • 4MW, 1 GeV on Hg? • Rotating/multiple targets/large beams (Ta, W)? 8Li • Similarities with 6He: should be possible • To be measured 8B • No beam ever produced • Many ideas exist. Need development (Frame-work, Priority?) • B is reactive (difficulties to get it out of the target) Nufact School 2009 10

  11. Ion production (overview) Aimed: He 2.9 1018 (2.0 1013/s after target) Ne 1.1 1018 (2.0 1013/s after target) Courtesy M. Lindroos N.B. Nuclear Physics has limited interest in those elements ->> Production rates not pushed! ISOL method at 1-2 GeV (200 kW) • >1 10136He per second • <8 101118Ne per second • Studied within EURISOL Direct production • >1 1013 (?) 6He per second • 1 101318Ne per second • 8Li ? • Studied at LLN, Soreq, WI and GANIL Production ring • 1014 (?) 8Li • >1013 (?) 8B • Will be studied Within EUROn Nufact School 2009 11

  12. In-flight and ISOL “ISOL: Such an instrument is essentially a target, ion source and an electromagnetic mass analyzer coupled in series. The apparatus is said to be in-flight when the material analyzed is directly the target of a nuclear bombardment, where reaction products of interest formed during the irradiation are slowed down and stopped in the system. H. Ravn and B.Allardyce, 1989, Treatise on heavy ion science In-Flight: ISOL: Post system Gas catcher Driver-beam Thin target Thick hot ISOL target Nufact School 2009

  13. 6He production from 9Be(n,a) • Converter technology preferred to direct irradiation (heat transfer and efficient cooling allows higher power compared to insulating BeO). • 6He production rate is ~2x1013 ions/s (dc) for ~200 kW on target. Converter technology: (J. Nolen, NPA 701 (2002) 312c) Nufact School 2009

  14. New approach for ion production “Beam cooling with ionisation losses” – C. Rubbia, A Ferrari, Y. Kadi and V. Vlachoudis in NIM A 568 (2006) 475–487 “Development of FFAG accelerators and their applications for intense secondary particle production”, -- Y. Mori, NIM A 562(2006)591 7Li(d,p)8Li 6Li(3He,n)8B 7Li 6Li 20-30 MeV • Stripping • Production • Coling From C. Rubbia, et al. in NIM A 568 (2006) 475–487 Multiple turns to increase production Nufact School 2009 14

  15. Beta Beam scenario EUROnu, FP7 Ion Linac 20 MeV n-beam to experiment 8B/8Li PR Ion production Decay ring Br ~ 500 Tm B = ~6 T C = ~6900 m Lss= ~2500 m 8Li: g = 100 18B: g = 100 ISOL target, Collection SPS Neutrino Source Decay Ring Existing!!! 60 GHz pulsed ECR Linac, 0.4 GeV PS2 92 GeV 31 GeV . RCS, 5 GeV Detector Gran Sasso Nufact School 2009

  16. Collection device A large proportion of beam particles (6Li) will be scattered into the collection device. The scattered primary beam intensity could be up to a factor of 100 larger than the RI intensity for 5-13 degree using a Rutherford scattering approximation for the scattered primary beam particles (M. Loislet, UCL) The 8B ions are produced in a cone of 13 degree with 20 MeV 6Li ions with an energy of 12 MeV±4 MeV (33% !). 8B-ions Rutherford scattered particles Collection off axis (Wien Filter) 8B-ions Collection on axis Cross section of B production is needed! Nufact School 2009

  17. Transverse cooling • Particle loses momentum P( and ||) in material • Particle regains P||(only) in RF • Multiple Scattering in material increases rmsemittance: Nufact School 2009 17

  18. Transverse cooling Loss of transverse momentum in absorber: Heating by multiple scattering Nufact School 2009 18

  19. 60 GHz « ECR Duoplasmatron » for gaseous RIB 2.0 – 3.0 T pulsed coils or SC coils Very high density magnetized plasma ne ~ 1014 cm-3 Small plasma chamber F ~ 20 mm / L ~ 5 cm Target Arbitrary distance if gas Rapid pulsed valve ? • 1-3 mm 100 KV extraction UHF window or « glass » chamber (?) 20 – 100 µs 20 – 200 mA 1012 per bunch with high efficiency 60-90 GHz / 10-100 KW 10 –200 µs /  = 6-3 mm optical axial coupling optical radial (or axial) coupling (if gas only) P.Sortais et al. Nufact School 2009

  20. Dedicated Linac for beta beams Elena Wildner, June -09 Nufact School 2009

  21. A double pre-injector Elena Wildner, June -09 Nufact School 2009

  22. Charge state distribution! Elena Wildner, June -09 Nufact School 2009

  23. Intensity Increase of Beta-Beams by Acceleration of Multiple-Charge State Neon Isotopes (not baseline) Linac 12 MeV/u 100 MeV/u ECR Linac-1 Linac-2 LEBT Stripper 1) Extract from the ECR several charge states of 18Ne isotopes 2) Accelerate 3 charge states of 18Ne5+, 18Ne6+, 18Ne7+, up to ~12 MeV/u (Linac1) 3) Fully strip to produce 18Ne10+ 4) Accelerate 18Ne10+ up to ~100 MeV/u (Linac-2) 5) Provide high quality 18Ne10+ beams for further acceleration Peter Ostroumov, ANL Nufact School 2009

  24. 20 bunches B SPS t 2 ms 2 ms SPS: injection of 20 bunches from PS. Acceleration to decay ring energy and ejection. PS: 1 s flat bottom with 20 injections. Acceleration in ~1 s to ~86.7 Tm.. B B 1 s 1 s PS PS t t RCS: further bunching to ~100 ns Acceleration to ~ 15 Tm. 20 repetitions during 1 s. Post accelerator linac: acceleration to ~100 MeV/u. 20 repetitions during 1 s. 60 GHz ECR: accumulation for 1/20 s ejection of fully stripped ~50 ms pulse. 20 batches during 1 s. t t Target: dc production during 1 s. 1 s 1 s 7 s From dc to very short bunches Nufact School 2009

  25. Intensity evolution during acceleration Cycle optimized for neutrino rate towards the detector • 30% of first 6He bunch injected are reaching decay ring • Overall only 50% (6He) and 80% (18Ne) reach decay ring • Normalization • Single bunch intensity to maximum/bunch • Total intensity to total number accumulated in RCS Bunch 20th 15th 10th 5th 1st total Nufact School 2009

  26. Momentum collimation merging p-collimation injection decay losses Arc Straight section Arc Straight section Particle turnover • ~1 MJ beam energy/cycle injected •  equivalent ion number to be removed • ~25 W/m average • Momentum collimation: ~5*10126He ions to be collimated per cycle • Decay: ~5*10126Li ions to be removed per cycle per meter Nufact School 2009 26

  27. Challenges: low dutycycle, short bunches Longitudinal merging in the decay ring Mandatory for success of the g=100 Beta-Beam concept Lifetime of ions (minutes) is much longer than cycle time (seconds) of a beta-beam complex 1) Injection, off momentum 3a) Single merge Merging: “oldest” particles pushed outside longitudinal acceptance  momentum collimation 2) Rotation 3b) Repeated merging Nufact School 2009

  28. Open Midplane Superconducting Dipole Scale arbitrary • Design ok for the present layout of the decay ring • check for energy deposition • radio protection (B and Li) • check if larger apertures with liner a better option E. Wildner, CERN Acknowledgments (magnet design, cryostating, cryogenics): Jens Bruer, F Borgnolutti, P. Fessia, R. van Weelderen , L. Williams and E. Todesco (CERN) Nufact School 2009

  29. Open mid-plane Quadrupole Mid-plane • In a quadrupole beam losses are mainly located in the mid-plane: • Damage the superconducting cable • Might lead to a quench • To avoid the peak of the heat deposition an open mid-plane can be inserted • How is the field strength (gradient) affected by insertion of an open mid-plane? Energy deposited Open mid-plane Acknowledgments (magnet design): F Borgnolutti, E. Todesco (CERN) Nufact School 2009 29

  30. Open mid-plane Quadrupole • We consider a quadrupole made of 2 pure sector blocks of the LHC main dipole cable. • Ironless coil is assumed. • Aperture diameter corresponding to a nominal gradient of 42 T/m with 20 % margin from the quench: • 2º opening : 220 mm • 4º opening : 180 mm • 6º opening : 130 mm Opening angle Acknowledgments (magnet design): F Borgnolutti, E. Todesco (CERN) Nufact School 2009

  31. Dynamic vacuum • Decay losses cause degradation of the vacuum due to desorption from the vacuum chamber • The current study includes the PS, which does not have an optimized lattice for unstable ion transport and has no collimation system • The dynamic vacuum degrades to 3*10-8 Pa in steady state (6He) • An optimized lattice with collimation system would improve the situation by more than an order of magnitude. C. Omet et al., GSI P. Spiller et al., GSI Elena Wildner, June -09 Nufact School 2009

  32. Airborne activity released in the environment: dose to the reference population • No apparent show stoppers but more studies needed • SPS not yet calculated

  33. Ions move almost at the speed of light What is important for the decay ring? • The atmospheric neutrino background is large at 500 MeV, the detector can only be open for a short moment every second • The decay products move with the ion bunch which results in a bunched neutrino beam • Low duty cycle – short and few bunches in decay ring • Accumulation to make use of as many decaying ions as possible from each acceleration cycle Only “open” when neutrinos arrive Elena Wildner, June -09 Nufact School 2009

  34. Barrier buckets, for high-Q ions • For the same gamma, with higher Q • We need 5 times more ions in decay ring • (M= g /Q and QEUROnu/QEURISOL~ 5 ) ??? • Since neutrino energy is higher, background in detector can be overcome ??? • Fill decay ring: try barrier buckets for injection • If background can be handled for gamma=100, we can fill ring completely also for Ne and He Nufact School 2009

  35. Duty factor for He/Ne .... 20 bunches, 10 ns long, distance 23*4 nanosseconds filling 1/11 of the Decay Ring, repeated every 23 microseconds Bunch length? If long, space charge is less important also in PS2! Elena Wildner, June -09 Nufact School 2009 35

  36. Barrier buckets for He (comparison) • Courtesy Christian, Hansen May 2009 Nufact School 2009

  37. He/Ne & Li/B o 3.13 x1012 1.04 x1014 • Courtesy Christian Hansen May 2009 Nufact School 2009

  38. No dutycycle, max filling Nufact School 2009

  39. ISOL, Rare Earth Metals Other possible scenarios in a beta beam complex • Electron capture and beta decay, Barnabeu et. al* • Electron capture: mono energetic n-beam • One species only • Interesting physics reach Yb… • Similarities with 18Ne • To be studied (Frame-work, Priority?) • 4MW, 1 GeV on Hg? • Rotating/multiple targets/large beams (Ta, W)? * arXiv: 0902.4303v1 [hep-ph] 27 Feb 2009 Nufact School 2009 39

  40. Chasing good isotopes for b decay and e-capture… Can background be suppressed ? Nufact School 2009

  41. Gamma and decay-ring size, 6He Magnet R&D New SPS Civil engineering Elena Wildner, June -09 Nufact School 2009 41

  42. n-factory History • US studies 1, 2 and 2a • • CERN Design study • • JPARC Design study ‘90 • • BENE FP6 • • ISS-NF 2005-2006 • • IDS-NF since 2007 • • EUROn 2008 (summer) Elena Wildner, June -09 Nufact School 2009 42

  43. Then-beam Elena Wildner, June -09 Nufact School 2009 43

  44. Neutrino factory baseline design New SPS Nufact School 2009

  45. Proton Driver (several options !) Elena Wildner, June -09 Nufact School 2009 45

  46. The Linac, RCS, NFFAG option Elena Wildner, June -09 Nufact School 2009 46

  47. The Linac/Compressor Ring option Elena Wildner, June -09 Nufact School 2009 47

  48. The Linac/Compressor Ring option FNAL - HINS Injector for Project X :60 MeV RFQ/Chopper/Linac 50 Hz (5 Hz), 30 mA, , 1ms, 325 MHz (1.3 GHz - SC ILC technology) CERN Injector for SPL: 3 MeV RFQ/Chopper 50 Hz, 70 mA, 0.4 ms, 352 MHz (704 MHz) RAL Injector for ISIS upgrade 3 MeV RFQ/Chopper - 50 Hz, 60 mA, 2 ms, 324 MHz Elena Wildner, June -09 Nufact School 2009 48

  49. Targets for muon production • Protons hit target, make pions, decay to muons • Production different for different materials • Prefer heavy metals • Target damage from proton beam • Stess on solid targets • Liquid jet, powder, rotating targets • Number of pulses and number of particles per pulse to be optimized Nufact School 2009

  50. Targets for muon production • 40 MW power (needed count) • 50 Hz repetition rate (space charge) • 5-15 GeV energy (peak production per power) • 1-3 ns RMS bunch length (production drops for longer bunches) • 3 bunches per repetition Elena Wildner, June -09 Nufact School 2009 50

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