The Beta-beam http://beta-beam.web.cern.ch/beta-beam/

1
The Beta-beamhttp//beta-beam.web.cern.ch/beta-be
am/

• Thomas Nilsson and Mats Lindroos
• on behalf of the
• The beta-beam study group

2
Collaborators

• The beta-beam study group
• CEA, France Jacques Bouchez, Saclay, Paris
  Olivier Napoly, Saclay, Paris Jacques Payet,
  Saclay, Paris
• CERN, Switzerland Michael Benedikt, AB Peter
  Butler, EP Roland Garoby, AB Steven Hancock, AB
  Ulli Koester, EP Mats Lindroos, AB Matteo
  Magistris, TIS Thomas Nilsson, EP Fredrik
  Wenander, AB
• Geneva University, Switzerland Alain Blondel
  Simone Gilardoni
• GSI, Germany Oliver Boine-Frankenheim B. Franzke
  R. Hollinger Markus Steck Peter Spiller Helmuth
  Weick
• IFIC, Valencia Jordi Burguet Juan-Jose
  Gomez-Cadenas Pilar Hernandez
• IN2P3, France Bernard Laune, Orsay, Paris Alex
  Mueller, Orsay, Paris Pascal Sortais, Grenoble
  Antonio Villari, GANIL, CAEN Cristina Volpe,
  Orsay, Paris
• INFN, Italy Alberto Facco, Legnaro Mauro
  Mezzetto, Padua Vittorio Palladino, Napoli Andrea
  Pisent, Legnaro Piero Zucchelli, Sezione di
  Ferrara
• Louvain-la-neuve, Belgium Thierry Delbar Guido
  Ryckewaert UK Marielle Chartier, Liverpool
  university Chris Prior, RAL and Oxford university
  
• Uppsala university, The Svedberg laboratory,
  Sweden Dag Reistad
• Associate Rick Baartman, TRIUMF, Vancouver,
  Canada Andreas Jansson, Fermi lab, USA

3
Outline

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

4
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

5
Neutrino oscillations

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

2
A. Blondel
6
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

7
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
8
Beam parameters in the decay ring

• 18Neon10 (single target)
• 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 should have
  the time stamp of the circulating beam in
  the decay ring.
• The beam has to be concentrated to as few and as
  short bunches as possible to maximize the number
  of ions/nanosecond. (background suppression)

9
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

10
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.
11
Mercury jet converter
H.Ravn, U.Koester, J.Lettry, S.Gardoni, A.Fabich
12
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

13
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)
14
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

15
Rapid Cycling Synchrotron and storage ring
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?

16
Overview Accumulation

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

17
PS
SPL
ISOL Target ECR
Linac, cyclotron or FFAG
Rapid 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

18
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

19
Decay ring
SPL
ISOL Target ECR
Linac, cyclotron or FFAG
Rapid 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

20
Injection into the decay ring

• Bunch merging requires fresh bunch to be injected
  at 10 ns distance 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.

21
Overview Decay ring

• Ejection to matched dispersion trajectory
• Asymmetric bunch merging

22
Asymmetric bunch merging
S. Hancock
23
Asymmetric bunch merging
24
Decay losses

• Losses during acceleration are being studied
• Full FLUKA simulations in progress for all stages
  (M. Magistris, CERN-TIS)
• Preliminary results
• Can be managed in low energy part
• PS will be heavily activated
• New fast cycling PS?
• SPS OK!
• Full FLUKA simulations of decay ring losses
• Tritium and Sodium production surrounding rock
  well below national limits
• Reasonable requirements of concreting of tunnel
  walls to enable decommissioning of the tunnel and
  fixation of Tritium and Sodium

A. Jansson
25
SC magnets

• Dipoles can be built with no coils in the path of
  the decaying particles to minimize peak power
  density in superconductor
• The losses have been simulated and a first dipole
  design has been proposed

S. Russenschuck, CERN
26
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

FLUKA simulated losses in surrounding rock
27
Intensities
Stage 6He 18Ne (single target)
From ECR source 2.0x1013 ions per second 0.8x1011 ions per second
Storage ring 1.0x1012 ions per bunch 4.1x1010 ions per bunch
Fast cycling synch 1.0x1012 ion per bunch 4.1x1010 ion per bunch
PS after acceleration 1.0x1013 ions per batch 5.2x1011 ions per batch
SPS after acceleration 0.9x1013 ions per batch 4.9x1011 ions per batch
Decay ring 2.0x1014 ions in four 10 ns long bunch 9.1x1012 ions in four 10 ns long bunch
Only b-decay losses accounted for, add efficiency
losses (50)
28
New ideas

• Work in progress on
• Multiple targets for Ne production
• Factor of three considered possible
• Ne and He in the decay ring simultaneously
• Low energy beta facility (C. Volpe)
• GSI, GANIL and CERN (in close detector)

29
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 OK
• Detector simulation should give best compromise
• Requiring equal revolution time will result in a
  DR of 20 mm (R01090 m)
• Manageable

30
Accumulation Ne He
31
CERN to FREJUS
32
The Super Beam
33
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
34
Physics reach CP-violation
M. Mezzetto
35
Superbeam Beta Beam cost estimates (NUFACT02)
36
Conclusions

• Physics
• Strong interest from community
• Super beam, beta-beam and FREJUS WORLD unique
• Low energy beta-beam other sites
• A concept 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!
• Design study proposal is now being prepared
• You are welcome to join (contact
  Mats.Lindroos_at_cern.ch)