Beta Beams
Elena Wildner, CERN
For the Beta Beam Collaboration
2011-07-23
HEP 2011, Beta Beams, Elena Wildner
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The Beta Beam Facility Collaborations
P. Zuchelli:” A novel concept for a neutrino factory: the betabeam”, Phys. Let. B, 532 (2002) 166-172.
FP6 “Research Infrastructure Action - Structuring the European
Research Area” EURISOL DS Project Contract no. 515768 RIDS)
Ended 2008
http://beta-beam.web.cern.ch/beta-beam/task/index.asp
FP7 “Design Studies” (Research Infrastructures) EUROnu (Grant
agreement no.: 212372)
Ongoing work from 2008
Lasts till fall 2012
http://heplnv135.pp.rl.ac.uk/joomla/index.php?option=com_content&view=category&id=9&Itemid=12
http://heplnv135.pp.rl.ac.uk/joomla/
Focus on a feasible and realistic facility with good physics reach
2011-07-23
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Neutrino Beams from Beta Beams
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Produce suitable beta (+/-) active isotopes
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Accelerate beta active isotopes
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2011-07-23
Available reaction energy of a specific isotope: Q
The ions will get a maximum gamma boost gmax (En  2gmaxQ)
Store them and let them decay in a race track storage ring
gmax
 depends on the available accelerators
 depends on the Z/A of the ion
 is chosen for the physics reach wanted
Merit factor: g/Q
 Lower flux with distance
 Higher x-sections with energy
 Higher flux with g
HEP 2011, Beta Beams, Elena Wildner
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High-Q and Low-Q pairs
Isotope
6He
18Ne
A/Z
3
1.8
decay
b-
b+
t1/2 [s]
0.81
1.67
Q [MeV] 3.51
3.0
Isotope
8Li
8B
A/Z
2.7
1.6
decay
b-
b+
t1/2 [s]
0.83
0.77
Q [MeV] 12.96
8Li and 8B
6He and 18Ne
t1/2 at rest (ground state)
1ms – 1s
1 – 60 s
NuBase
13.92
Higher Q-value gives higher n-energy, better x-sections but needs longer baseline
2011-07-23
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Beta beams at CERN
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Use of CERN machines and infrastructures, existing technology
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SPS allows maximum of 150 (6He) or 250 (18Ne)
Gamma choice optimized for physics reach
Opportunity to share detectors with astrophysics etc. ???
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beta beams (CERN)
Relativistic gamma=100 for both ions
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Beta Beam are unique to CERN
Bunching and first acceleration: ECR, linac
Rapid cycling synchrotron
Use of existing machines: PS and SPS
Frejus, Gran Sasso, Canfranc, CNGS-Umbria, …
Minimum n-rates after Decay Ring for physics reach
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2.9*1018 anti-neutrinos from 6He
1.1 1018 neutrinos from 18Ne
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CERN Beta Beams, Synoptic
RCS
SPL
Dotted lines: alternative layouts
Linac4
Linac
Molten
Salt Loop
ISOL
target
6He
Collection
PR
18Ne
n-Beam
8B/8Li
Baseline
6He/18Ne
ECR
RFQ
Linac 100 MeV
DR
PS
SPS
PS and SPS existing
RCS
Decay Ring: Br ~ 500 Tm, B = ~6 T, C = ~6900 m, Lss= ~2500 m, g = 100, all ions
2011-07-23
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CERN Beta Beams, Synoptic
SPL
RCS
Linac4
ISOL
target
Dotted lines: alternative layouts
Molten
Salt Loop
6He
n-Beam Fréjus
18Ne
ECR
RFQ
6He/18Ne
Linac 100 MeV
DR
PS
SPS
PS and SPS existing
RCS
Br ~ 500 Tm, B = ~6 T, C = ~6900 m, Lss= ~2500 m, g = 100, all ions
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EUROnu physics
Gamma 100
Gamma 100
Gamma 350
Gamma 350
Gamma 350
M. Mezetto
2011-07-23
Gamma 100
HEP 2011, Beta Beams, Elena Wildner
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CPV
The systematic error estimation is important (detectors and beam)
Beta beam neutrino flux can be calculated with current monitors in the accelerator.
Extend plots (calculations) to higher theta13
Reduction of Suppression needed for atmospheric background !!!
2011-07-23
HEP 2011, Beta Beams, Elena Wildner
Flux
Systematics
SF
Flux
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CPV for the Fréjus option (6He&18Ne)
Courtesy E. Fernandez, P. Coloma, C. Hansen
• SF for atmospheric bg suppression:
•serious constraint for bBeams
• Larger sin22q13
•constraint is relaxed
•larger bunches permitted
•higher neutrino fluxes
• Calculations should be extended
• range beyond Chooz limit ?
SF 2% seems sufficient for larger sin22q13 (0.6% used up till now)
2011-07-23
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CPV - nFlux: Fréjus &Canfranc
Courtesy E. Fernandez, P. Coloma, C. Hansen
Nominal flux
2*Nominal flux
5*Nominal flux
Fréjus, SF 1%
Canfranc, SF 1%
Fréjus:18Ne (1.1 1018 n/year) & 6He (1.1 1018 n/year), g=100
Canfranc:18Ne (4.4 1017 n/year, g=250) & 8He (2.9 1018 n/year, g=100)
Other ion combinations may be efficient (A. Donini)
Systematics from big fiducial volume not good
Liquid Argon for Canfranc?
2011-07-23
Dashed SuperBeam to Fréjus
Negative delta, matter effects give degeneracies
with the mass hierarchy.
Larger flux: no degeneracies, sensitivity for
negative delta would increase, measurement of
the mass hierarchy would be possible
HEP 2011, Beta Beams, Elena Wildner
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Mass Hierarchy
Canfranc, Beta Beam setting:
8Li@100 and 18Ne@250
Flux:
2* Nominal
5* Nominal
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Beta Beam Challenges
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Isotope production ok now !
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Atmospheric background suppression
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We loose particles from necessary collimation
We get short intense bunches in the Decay Ring, may get unstable
We can relax the suppression with recent results from T2K!
High intensities in the existing machines
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n emmitters “easy” to produce, measured rates are sufficient
n are more difficult: we can make them “on paper”
Exp. for Ne18 production verification are ongoing
Beam instabilities
Radiation
Follow carefully the LHC injector upgrades
The present machine cycles
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Optimization possible
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Isotope production rates
Aim: 2.0 1013 for low-Q
More is possible
Targets below MWatt is a considerable advantage!
Planned experiments
NB :8Li can be produced in rates comparable to 6He using similar technology
T. Stora, P Valko, E. Benedetto, E. Wildner…
2011-07-23
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Status, technologies
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SF in Decay Ring (CERN, Cockroft)
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60 GHz Ion Source (LPSC, CNRS, Grenoble)
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Analysis of results available in September
Decay Ring Redesigned (CEA)
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Collection ok
Efficiencies now measured
Measurements of x-sections 8B and 8Li (INFN, Legnaro)
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Tests of magnetic field for plasma containment ok
Tests of assembly with 28 GHz (emmittances and efficiencies)
60 GHz gyrotron: awaiting reception 2012
Collection of high-Q ions from production ring (UCL, Louvain)
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RF hardware seems feasible
Collective effects less important
Collimation in Decay Ring (CERN)
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Needs good solution
2011-07-23
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Implementation and Costing
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How to chose a facilty?
Performance/Cost
Part of EUROnu mandate
Synergy bB/SB
Safety has to be included
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Conclusion
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T2K: Optimization for excellent physics reach is ongoing
We can now reduce the SF for bg suppression (if T2K)
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Optimization of L/E
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Detector, WC but also Liquid Argon (EUROnu WP5)
Beam (alignment and current monitoring in accelerator)
To be included in the comparison analysis (all facilities)
Technical work in very good progress
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SPS can give gamma up to 250 for 18Ne, may be interesting now
Systematic errors need complete evaluation
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Flux will be considerably increased
isotope production confirmed for 6He, 18Ne experiment ongoing
Ion source being tested
Cross section measurements for high-Q isotopes ok
All results have to be iterated
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2011-07-23
Work on physics and accelerators in collaboration to be continued
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The Production Ring (8B and 8Li)
Production of 8B and 8Li
C. Rubbia, EUROnu proposal
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Aachen Univ., GSI, CERN
Gas Jet target proposed in FP7:
 too high density would be needed
 vacuum problems
Direct Production (D. Neuffer) with liquid film targets
 Collaboration ANL (Benedetto/Nolen)
 High-Q 8B and 8Li will not be considered for the time being
 We will not explore the low-Q gamma 350 option
2011-07-23
HEP 2011, Beta Beams, Elena Wildner
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Managing intensities: “Ion Cocktails”
Collective effects important
Less collective effects
Summary by A. Donini
2011-07-23
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Collective Effects limits, Decay Ring
Only Transverse Mode Coupling Instabilities
Recent Encouraging results, redesigned decay ring !
Phase slip factor changed
C. Hansen, CERN & A. Chance, CEA
2011-07-23
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Atm. Background suppression
1014 ions, ~0.5% duty (supression) factor can now be reduced
Gives possibilities to give more neutrino flux
20 bunches, 5.2 ns long, distance 23*4 nanosseconds
filling 1/11 of the Decay Ring, repeated every 23 microseconds
2011-07-23
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Collection device
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Measurements/Analysis ongoing for the collected 8Li
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Direct kinematics is possible, efficiencies to be evaluated
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Setup and measurements for 8B production and collection ongoing
CRC, Louvain la Neuve
2011-07-23
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X-sections, Energies and Angles, Li and B
INFN, Legnaro
2011-07-23
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60 GHz Source status
Puller
electrode
Plasma
electrode
Extraction
insulator
High voltage
ring
28 GHz
waveguide
Conceptual design of the internal parts of the ECRIS
prototype
Delivery of the GANIL 28 GHz gyrotron to LPSC
LPSC-LNCMI discussions for experiments
Ion beam at 28 GHz with SEISM prototype (fall 2011)
Magnetic field measurements, 30000 A (60 GHz)
Plasma chamber
Design of the High intensity beam line
Follow-up the 60 GHz gyrotron building
LPSC Euronu contract status
Hiring a one year post-doc
400 A Power supply
and
magnet
2011-07-23
2010-06-04
HEP 2011, Beta Beams, Elena Wildner
T. Lamy
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