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RNB 6 The beta-beam study group
The Beta-beamhttp://beta-beam.web.cern.ch/beta-beam/
Thomas Nilsson and Mats Lindroos
on behalf of the The beta-beam study
group
RNB 6 The beta-beam study group
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
RNB 6 The beta-beam study group
Outline
• Neutrino oscillations• The beta-beam
– Overview– The CERN base line scenario
– The Moriond workshop
• The super beam• Conclusions
RNB 6 The beta-beam study group
Neutrinos• A mass less particle predicted by Pauli to explain the
shape of the beta spectrum• Exists in at least three flavors (e, , )• 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
RNB 6 The beta-beam study group
Neutrino oscillations• Three neutrino mass states (1,2,3) and three
neutrino flavors (e,,)
23(atmospheric) = 450 , 12(solar) = 300 , 13(Chooz) < 130
Unknown or poorly known even after approved program:13 , phase , sign of m13 2
OR?
m223= 3 10-3eV2
m212= 3 10-5 - 1.5 10-4 eV2
m212= 3 10-5 - 1.5 10-4 eV2
m223= 3 10-3eV2
A. Blondel
RNB 6 The beta-beam study group
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
RNB 6 The beta-beam study group
CERN: -beam baseline scenario
PS
Decay
RingISOL target & Ion source
SPL
Cyclotrons, linac or FFAG
Decay ring
Brho = 1500 Tm
B = 5 T
Lss = 2500 m
SPS
ECR
Rapid cycling synchrotron
MeV 86.1 Average
MeV 937.1 Average
189
1810
63
62
cms
cms
E
eFeNe
E
eLiHe
Nuclear Physics
RNB 6 The beta-beam study group
Beam parameters in the decay ring
18Neon10+ (single target)– Intensity: 4.5x1012 ions – Energy: 55 GeV/u– Rel. gamma: 60– Rigidity: 335 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)
6Helium2+
– Intensity: 1.0x1014 ions – Energy: 139
GeV/u– Rel. gamma: 150– Rigidity: 1500 Tm
RNB 6 The beta-beam study group
SPL, ISOL and ECR
Objective:• Production, ionization and pre-bunching of ionsChallenges:• Production of ions with realistic driver beam
current– Target deterioration
• Accumulation, ionization and bunching of high currents at very low energies
SPLISOL Target + ECR
Linac, cyclotron or FFAG
Rapidcycling
synchrotronPS SPS
Decay ring
RNB 6 The beta-beam study group
Layout very similar to planned EURISOL converter target aiming for 1015 fissions per s.
66He production by He production by 99Be(n,a)Be(n,a)
Converter technology: (J. Nolen, NPA 701 (2002) 312c)
RNB 6 The beta-beam study group
Mercury jet converter
H.Ravn, U.Koester, J.Lettry, S.Gardoni, A.Fabich
RNB 6 The beta-beam study group
Scenario 1Scenario 1
• Spallation of close-by target nuclides:18,19Ne from MgO and 34,35Ar in CaO
– Production rate for 18Ne is 1x1012 s-1 (with 2.2 GeV 100 A 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 2Scenario 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
Production of Production of ++ emitters emitters
RNB 6 The beta-beam study group
60-90 GHz « ECR Duoplasmatron » for gaseous RIB
Very high densitymagnetized plasma
ne ~ 1014 cm-3
2.0 – 3.0 T pulsed coils or SC coils
60-90 GHz / 10-100 KW10 –200 µs / = 6-3 mm
optical axial coupling
optical radial coupling(if gas only)
1-3 mm100 KV
extractionUHF windowor « glass » chamber (?)
Target
Rapid pulsed valve
20 – 100 µs20 – 200 mA
1012 to 1013 ions per bunchwith high efficiency
Very small plasmachamber ~ 20 mm / L ~ 5 cm
Arbitrary distanceif gas
Moriond meeting:
Pascal Sortais et al.
ISN-Grenoble
RNB 6 The beta-beam study group
Low-energy stage
Objective:• Fast acceleration of ions and
injection• Acceleration of 16 batches to 20
MeV/u
SPLISOL Target + ECR
Linac, cyclotron or FFAG
Rapidcycling
synchrotronPS SPS
Decay ring
RNB 6 The beta-beam study group
Rapid Cycling Synchrotron and storage ring
Objective:• Accumulation, bunching (h=1), 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?
SPLISOL Target + ECR
Linac, cyclotron or FFAG
Rapidcycling
synchrotronPS SPS
Decay ring
RNB 6 The beta-beam study group
Overview: Accumulation
• Sequential filling of 16 buckets in the PS from the storage ring
RNB 6 The beta-beam study group
PS
• Accumulation of 16 bunches at 300 MeV/u
• Acceleration to =9.2, 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
SPLISOL Target + ECR
Linac, cyclotron or FFAG
Rapid cycling
synchrotronPS SPS
Decay ring
RNB 6 The beta-beam study group
SPS
Objective:• Acceleration of 8 bunches of 6He(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 ringChallenges:• Transverse acceptance
SPLISOL Target + ECR
Linac, cyclotron or FFAG
Fast cycling
synchrotronPS SPS
Decay ring
RNB 6 The beta-beam study group
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
SPLISOL Target + ECR
Linac, cyclotron or FFAG
Rapidcycling
synchrotronPS SPS
Decay ring
RNB 6 The beta-beam study group
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 s).
– Maximum flexibility for adjusting the relative distance bunch to stack on ns time scale.
RNB 6 The beta-beam study group
SPS
Overview: Decay ring
• Ejection to matched dispersion trajectory
• Asymmetric bunch merging
SPSSPS
RNB 6 The beta-beam study group S. Hancock
Asymmetric bunch merging
RNB 6 The beta-beam study group
Asymmetric bunch merging
60 40 20 0 20 40 60ns
4
2
0
2
4
MeV
0
0.1
0.2
0.3
0.4
0.5
A
4014
3014
2014
1014 0
eVe
0 5 10 15 20 25Iterations
0
8.17 1011
esVe
rms 0.0585 eVs BF 0.16
matched 0.298 eVs Ne 1.57 1011
2 prmsp 1.2 103 fs0;1 822;790 Hz
60 40 20 0 20 40 60ns
4
2
0
2
4
MeV
0
0.1
0.2
0.3
0.4
0.5
A
4014
3014
2014
1014 0
eVe
0 5 10 15 20 25Iterations
0
8.1 1011
esVe
rms 0.0639 eVs BF 0.168
matched 0.323 eVs Ne 1.6 1011
2 prmsp 1.25 103 fs0;1 823;790 Hz
125 100 75 50 25 0 25 50ns7.5
5
2.5
0
2.5
5
7.5
MeV
0
0.1
0.2
0.3
0.4
0.5
0.6
A
4014
3014
2014
1014 0
eVe
0 5 10 15 20 25Iterations
0
8.52 1011
esVe
rms 0.0583 eVs BF 0.14
matched 0.317 eVs Ne 1.63 1011
2 prmsp 1.34 103 fs0;1 0;1060 Hz
100 75 50 25 0 25 50 75ns4
2
0
2
4
MeV
0
0.1
0.2
0.3
0.4
A
6014
5014
4014
3014
2014
1014 0
eVe
0 10 20 30 40 50Iterations
0
8.16 1011
esVe
rms 0.0593 eVs BF 0.224
matched 0.333 eVs Ne 1.56 1011
2 prmsp 8.5 104 fs0;1 0;415 Hz
RNB 6 The beta-beam study group
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
RNB 6 The beta-beam study group
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
RNB 6 The beta-beam study group
Tunnels and Magnets• Civil engineering costs: Estimate of 400 MCHF for 1.3%
incline (13.9 mrad)– Ringlenth: 6850 m, Radius=300 m, Straight sections=2500 m
• Magnet cost: First estimate at 100 MCHF
FLUKA simulated losses in surrounding rock
RNB 6 The beta-beam study group
IntensitiesStage 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 -decay losses accounted for, add efficiency losses (50%)
RNB 6 The beta-beam study group
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)
RNB 6 The beta-beam study group
Ne and He in decay ring simultaneously
• Enormous “gain” in counting time– Years!
• Requiring =150 for He will at equal rigidity result in a =250 for Ne– Physics OK– Detector simulation should give “best”
compromise
• Requiring equal revolution time will result in a R of 20 mm (R0=1090 m)– Manageable
RNB 6 The beta-beam study group
Accumulation Ne + He
200 400 600 800 1000
5
10
15
20
25
30
6He8 s SPS cycling
6He16 s SPS cycling
Accumulation (multiplication)
factor
Time (s)
Requires larger long. Acceptance!
RNB 6 The beta-beam study group
CERN to FREJUSGeneve
Italy
130km
40kt400kt
CERN
SPL @ CERN2.2GeV, 50Hz, 2.3x1014p/pulse 4MWNow under R&D phase
RNB 6 The beta-beam study group
The Super Beam
RNB 6 The beta-beam study group
Combination of beta beam with low energy
super beamUnique to CERN:
combines CP and T violation tests
e (+) e (+)
e (-) e (-)
A. Blondel
CPCP
T
T
RNB 6 The beta-beam study group
Physics reach: CP-violation
M. Mezzetto
RNB 6 The beta-beam study group
Superbeam & Beta Beam cost estimates
(NUFACT02)Educated guess on possible costs USD/CHF 1.60UNO (DETECTOR) 960 MCHFSUPERBEAM LINE 100 MCHFSPL 300 MCHFPS UPGR. 100 MCHFSOURCE (EURISOL), STORAGE RING 100 MCHFSPS 5 MCHFDECAY RING CIVIL ENG. 400 MCHFDECAY RING OPTICS 100 MCHF
TOTAL (MCHF) 2065 MCHFTOTAL (MUSD) 1291 MUSD
INCREMENTAL COST (MCHF) 705 MCHFINCREMENTAL COST (MUSD) 441 MUSD
RNB 6 The beta-beam study group
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