The Betabeam http:betabeam'web'cern'chbetabeam

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The Beta-beamhttp//beta-beam.web.cern.ch/beta-be
am/

• Mats Lindroos on behalf of the
• The BENE beta-beam network

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Collaborators

• BENE beta-beam network
• GSI
• Helmuth Weick, Markus Steck, Peter Spiller,
  Oliver Boine-Frankenheim, R. Hollinger, B.
  Franzke
• CEA
• Olivier NAPOLY, Jacques Payet, Jacques Bouchez
• IN2P3
• Cristina Volpe, Alex Muelle, Pascal Sortais,
  Laune Bernard, Antonio Villar
• INFN
• Vittorio Palladino, Mauro Mezzetto, Alberto
  Facco, Andrea Pisent
• UK
• Chris Prior, Marielle Chartier
• CERN
• Mats Lindroos, Steven Hancock, Matteo Magistris,
  Simone Gilardoni, Fredrik Wenander, Roland
  Garoby, Michael Benedikt, Ulli Koester
• Geneva University
• Alain Blondel
• Louvain-la-neuve
• Guido Ryckewaert, Thierry Delbar
• Uppsala
• Dag Reistad

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Acknowledgements

• For kindly having assisted with this specific
  presentation
• M.Benedikt, A.Blondel, J.Bouchez, K.Elsener,
  S.Gilardoni, R.Garoby, S.Hancock, A.Jansson,
  U.Koester M.Magistris, S.Russenschuck, P.Sortais,
  C.Volpe, F.Wenander

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Outline

• Neutrino oscillations
• The beta-beam
• Overview
• The CERN base line scenario
• The Moriond workshop
• The super beam
• Conclusions

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Neutrinos

• A mass less particle predicted by Pauli to
  explain the shape of the beta spectrum
• Exists in at least three flavors (e, m, t)
• Could have a small mass which could significantly
  contribute to the mass of the universe
• The mass could be made up of a combination of
  mass states
• If so, the neutrino could oscillate between
  different flavors as it travel along in space

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Neutrino oscillations

• Three neutrino mass states (1,2,3) and three
  neutrino flavors (e,m,t)

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A. Blondel
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Objectives

• The beta-beam could be one component in the
  future European Neutrino Physics programme
• Present a coherent and realistic scenario for a
  beta-beam facility
• Use known technology (or reasonable
  extrapolations of known technology)
• Use innovations to increase the performance
• Re-use a maximum of the existing accelerators

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CERN b-beam baseline scenario
Decay ring Brho 1500 Tm B 5 T Lss 2500 m
SPL
SPS
Decay Ring
ISOL target Ion source
ECR
Cyclotrons, linac or FFAG
Rapid cycling synchrotron
PS
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Desired beam parameters in the decay ring

• 18Neon10
• Intensity 4.5x1012 ions
• Energy 55 GeV/u
• Rel. gamma 60
• Rigidity 335 Tm

• 6Helium2
• Intensity 1.0x1014 ions
• Energy 139 GeV/u
• Rel. gamma 150
• Rigidity 1500 Tm

• The neutrino beam at the experiment will have the
  time stamp of the circulating beam in the
  decay ring.
• We need to concentrate the beam in as few and as
  short bunches as possible to maximize the number
  of ions/nanosecond. (background suppression)
• Clearly 6He is the more demanding ion and
  considered further on .

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SPL, ISOL and ECR
SPL
ISOL Target ECR
Linac, cyclotron or FFAG
Rapid cycling synchrotron
PS
SPS
Decay ring

• Objective
• Production, ionization and pre-bunching of ions
• Challenges
• Production of ions with realistic driver beam
  current
• Target deterioration
• Accumulation, ionization and bunching of high
  currents at very low energies

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6He production by 9Be(n,a)
Converter technology (J. Nolen, NPA 701 (2002)
312c)
Layout very similar to planned EURISOL converter
target aiming for 1015 fissions per s.
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Mercury jet converter
H.Ravn, U.Koester, J.Lettry, S.Gardoni, A.Fabich
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Production of b emitters

• Scenario 1
• Spallation of close-by target nuclides18,19Ne
  from MgO and 34,35Ar in CaO
• Production rate for 18Ne is 1x1012 s-1 (with 2.2
  GeV 100 mA proton beam, cross-sections of some mb
  and a 1 m long oxide target of 10 theoretical
  density)
• 19Ne can be produced with one order of magnitude
  higher intensity but the half life is 17 seconds!
• Scenario 2
• alternatively use (?,n) and (3He,n) reactions
• 12C(3,4He,n)14,15O, 16O(3,4He,n)18,19Ne,
  32S(3,4He,n)34,35Ar
• Intense 3,4He beams of 10-100 mA 50 MeV are
  required

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MONOECR (at ISOLDE)

• MINIMONO ISOLDE
• GANIL design 1,2
• standard ISOLDE unit
• permanent magnets
• consumable unit
• on-line test 2003

• ISOECRIS
• based on a ISOLDE unit
• coils
• consumable unit
• in production

F. Wenander, J.Lettry
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60-90 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
Very small plasma chamber F 20 mm / L 5 cm
Target
Arbitrary distance if gas
Rapid pulsed valve

• 1-3 mm
• 100 KV
• extraction

60-90 GHz / 10-100 KW 10 200 µs / ? 6-3
mm optical axial coupling
UHF window or  glass  chamber (?)
20 100 µs 20 200 mA 1012 to 1013 ions per
bunch with high efficiency
Moriond meeting Pascal Sortais et
al. ISN-Grenoble
optical radial coupling (if gas only)
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Low-energy stage
SPL
ISOL Target ECR
Linac, cyclotron or FFAG
Rapid cycling synchrotron
PS
SPS
Decay ring

• Objective
• Fast acceleration of ions and injection
• Acceleration of 16 batches to 20 MeV/u

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Rapid Cycling Synchrotron
SPL
ISOL Target ECR
Linac, cyclotron or FFAG
Rapid cycling synchrotron
PS
SPS
Decay ring

• Objective
• Accumulation, bunching (h1), acceleration and
  injection into PS
• Challenges
• High radioactive activation of ring
• Efficiency and maximum acceptable time for
  injection process
• Charge exchange injection
• Multiturn injection
• Electron cooling or transverse feedback system to
  counteract beam blow-up?

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Overview Accumulation

• Sequential filling of 16 buckets in the PS from
  the storage ring

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PS
SPL
ISOL Target ECR
Linac, cyclotron or FFAG
Fast cycling synchrotron
PS
SPS
Decay ring

• Accumulation of 16 bunches at 300 MeV/u
• Acceleration to g9.2, merging to 8 bunches and
  injection into the SPS
• Question marks
• High radioactive activation of ring
• Space charge bottleneck at SPS injection will
  require a transverse emittance blow-up

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OverviewPS to SPS
SPS
PS

• Merging in PS to 8 buckets
• Blow-up before transfer to manage space charge
  limit in SPS

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SPS
SPL
ISOL Target ECR
Linac, cyclotron or FFAG
Fast cycling synchrotron
PS
SPS
Decay ring

• Objective
• Acceleration of 8 bunches of 6He(2) to g150
• 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
• Challenges
• Transverse acceptance

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Decay ring
SPL
ISOL Target ECR
Linac, cyclotron or FFAG
Fast cycling synchrotron
PS
SPS
Decay ring

• Objective
• Injection of 4 off-momentum bunches on a matched
  dispersion trajectory
• Rotation with a quarter turn in longitudinal
  phase space
• Asymmetric bunch merging of fresh bunches with
  particles already in the ring

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Injection into the decay ring

• Bunch merging requires fresh bunch to be injected
  at 10 ns from stack!
• Conventional injection with fast elements is
  excluded.
• Off-momentum injection on a matched dispersion
  trajectory.
• Rotate the fresh bunch in longitudinal phase
  space by ¼ turn into starting configuration for
  bunch merging.
• Relaxed time requirements on injection elements
  fast bump brings the orbit close to injection
  septum, after injection the bump has to collapse
  within 1 turn in the decay ring (20 ms).
• Maximum flexibility for adjusting the relative
  distance bunch to stack on ns time scale.

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Overview Decay ring

• Ejection to matched dispersion trajectory
• Asymmetric bunch merging

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Horizontal aperture layout

• Assumed machine and beam parameters
• Dispersion Dhor 10 m
• Beta-function bhor 20 vm
• Moment. spread stack Dp/p 1.0x10-3 (full)
• Moment. spread bunch dp/p 2.0x10-4 (full)
• Emit. (stack, bunch) egeom 0.6 pmm

Beam 2 mm momentum 4 mm
emittance
Required bump 22 mm
Required separation 30 mm, corresponds to
3x10-3 off-momentum.
Septum alignment 10 mm

Stack 10mm momentum 4 mm
emittance
22 mm
Central orbit undisplaced
M. Benedikt
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Injection to decay ring
M. Benedikt
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Asymmetric bunch merging
S. Hancock
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Full scale simulation with SPS as model

• Simulation conditions
• Single bunch after injection and ¼ turn rotation.
• Stacking again and again until steady state is
  reached.
• Each repetition, a part of the stack
  (corresponding to b-decay) is removed.
• Results
• Steady state intensity was 85 of theoretical
  value (for 100 effective merging).
• Final stack intensity is 10 times the bunch
  intensity (15 effective mergings).
• Moderate voltage of 10 MV is sufficient for 40
  and 80 MHz systems for an incoming bunch of lt 1
  eVs.

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Decay losses

• Acceleration losses

A. Jansson
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How bad is 9 W/m?

• For comparison, a 50 GeV muon storage ring
  proposed for FNAL would dissipate 48 W/m in the
  6T superconducting magnets. Using a tungsten
  liner to
• reduce peak heat load for magnet to 9 W/m.
• reduce peak power density in superconductor
  (to below 1mW/g)
• Reduce activation to acceptable levels
• Heat load may be OK for superconductor.

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SC magnets

• Dipoles can be built with no coils in the path of
  the decay (one ion type) particles to minimise
  peak power density in superconductor (quench
  stability).

S. Russenschuck, CERN
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Tunnels and Magnets

• Civil engineering costs Estimate of 400 MCHF for
  1.3 incline (13.9 mrad)
• Ringlenth 6850 m, Radius300 m, Straight
  sections2500 m
• Magnet cost First estimate at 100 MCHF

Arc cross-section
CERN Cricket Club
Shielding
Tunnel
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Intensities 6He

• From ECR source 2.0x1013 ions per second
• Storage ring 1.0x1012 ions per bunch
• Fast cycling synch 1.0x1012 ion per bunch
• PS after acceleration 1.0x1013 ions per batch
• SPS after acceleration0.9x1013 ions per batch
• Decay ring 2.0x1014 ions in four 10 ns
  long bunch
• Only b-decay losses accounted for, efficiency lt50

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Intensities 18Ne

• From ECR source 0.8x1011 ions per second
• Storage ring 4.1x1010 ions per bunch
• Fast cycling synch 4.1x1010 ion per bunch
• PS after acceleration 5.2x1011 ions per batch
• SPS after acceleration4.9x1011 ions per batch
• Decay ring 9.1x1012 ions in four 10 ns
  long bunch
• Only b-decay losses accounted for, efficiency
  lt50

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Moriond meeting

• Annual electro week meeting in Les Arcs
• Workshop on Radioactive beams for Nuclear and
  Neutrino Physics
• Organizer Jacques Bouchez, CEA, Saclay
• Many new ideas, among them
• Multiple targets for Ne production
• ECR bunching (P. Sortais)
• Ne and He in the decay ring simultaneously
• Low energy beta facility (C. Volpe)
• GSI, GANIL and CERN (in close detector)

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Ne and He in decay ring simultaneously

• Enormous gain in counting time
• Years!
• Requiring g150 for He will at equal rigidity
  result in a g250 for Ne
• Physics?
• Detector simulation should give best compromise
• Requiring equal revolution time will result in a
  DR of 20 mm (R01090 m)
• Manageable?

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Accumulation Ne He
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CERN to FREJUS
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The Super Beam
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HERE 250 MeV NEUTRINOS
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Water CherenkowSuper Kamiokande
MultiUSER detector Astrophysics, Beta-beam,
Super Beam, Proton Decay
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Combination of beta beam with low energy super
beam
Unique to CERN combines CP and T violation
tests ?e ? ?m (?) ?m ? ?e (p) ?e
? ?m (?-) ?m ? ?e (p-)
A. Blondel
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SPL (8 MW) for many users
3ms 2.2 GeV for NuFact and Super Beam
15 mA
15 ms accelerated to 2.2 GeV for other Users
b beam
3 mA
20 ms
total power at 2.2 GeV 4 MW X 2 8 MW
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Physics reach
M. Mezzetto
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Superbeam Beta Beam cost estimates (NUFACT02)
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Conclusions

• Physics
• Strong interest from community
• Super beam, beta-beam and FREJUS WORLD unique
• Low energy beta-beam other sites
• A baseline scenario for the beta-beam exists
• While, possible solutions have been proposed for
  all identified bottlenecks we still have problems
  to overcome but
• you are invited to make proposals for
  improvements!
• Higher intensity in the decay ring
• First results are so encouraging that the
  beta-beam option should be fully explored

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Open questions

• among them
• Target (area) design
• EURISOL study (Design study in 6th EU FP)
• Efficiency of ECR chargebreeding and bunching
• Low energy acceleration
• LINAC/ECR/FFAG?
• Combined storage ring and Rapid Cycling
  Synchrotron
• Injection into Rapid Cycling Synchrotron
• PS do we need a new (Rapid cycling) machine?
• Space charge bottle neck from PS to SPS
• Lattice for decay ring
• Many constraints if Ne and He should be stored
  simultaneously
• Stability of short high intensity ion bunches in
  decay ring
• Magnet design for decay ring
• Civil engineering of decay ring
• Shielding issues to avoid groundwater activation

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Comment

• We are all working hard to complete the LHC and
  to keep CERN running
• In your already overloaded week try to find 2
  hours
• Spend one of these hours on our future
• CLIC
• Nufact
• Beta-beam
• And many more ideas
• Spend the other hour on LHC
• The succesfull completion of LHC is conditional
  for any long term future of CERN
• Thank you for your attention!