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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, Jose Bernabeu – 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, Mike Zisman, LBL, USA
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The beta-beam
• Idea by Piero Zucchelli– A novel concept for a neutrino factory: the
beta-beam, Phys. Let. B, 532 (2002) 166-172
• The CERN base line scenario– Avoid anything that requires a “technology
jump” which would cost time and money (and be risky)
– Make use of a maximum of the existing infrastructure
– If possible find an “existing” detector site
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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
,
,
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Target values for the decay ring
18Neon10+ (single target)– In decay ring: 4.5x1012
ions – Energy: 55 GeV/u– Rel. gamma: 60– Rigidity: 335 Tm
• The neutrino beam at the experiment will 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 aim for a duty factor of 10-4
6Helium2+
– In Decay ring: 1.0x1014 ions – Energy: 139 GeV/u– Rel. gamma: 150– Rigidity: 1500 Tm
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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
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ISOL production
1 GeV p
p n
2 3 8
U
2 0 1
F r
+ spallation
1 1
L i X
+ + fragmentation
1 4 3
C s Y
+ + fission
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Layout very similar to planned EURISOL converter target aiming for 1015 fissions per s.
66He production by He production by 99Be(n,Be(n,))
Converter technology: (J. Nolen, NPA 701 (2002) 312c)
Courtesy of Will Talbert, Mahlon Wilson (Los Alamaos) and Dave Ross (TRIUMF)
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• 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!
Production of Production of ++ emitters emitters
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60-90 GHz « ECR Duoplasmatron » for pre-bunching of 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.
LPSC-Grenoble
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Low-energy stage
Objective:• Fast acceleration of ions and
injection• Acceleration of 16 batches to 100
MeV/u
SPLISOL Target + ECR
Linac, cyclotron or FFAG
Rapidcycling
synchrotronPS SPS
Decay ring
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Rapid Cycling Synchrotron
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
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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
Fast cycling
synchrotronPS SPS
Decay ring
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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
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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
Fast cycling
synchrotronPS SPS
Decay 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 s).
– Maximum flexibility for adjusting the relative distance bunch to stack on ns time scale.
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Horizontal aperture layout
• Assumed machine and beam parameters:– Dispersion: Dhor = 10 m
– Beta-function: hor = 20 √m– Moment. spread stack: p/p = ±1.0x10-3 (full)– Moment. spread bunch: p/p = ± 2.0x10-4 (full)– Emit. (stack, bunch): geom = 0.6 m
Septum & alignment 10 mm
Stack: ± 10mm momentum
± 4 mm emittance
Beam: ± 2 mm momentum
± 4 mm emittanceRequired separation:30 mm, corresponds to 3x10-3 off-momentum.
Required bump:22 mm
22 mm
Central orbit undisplacedM. Benedikt
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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 -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 < 1 eVs.
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SPS
Stacking in the Decay ring
• Ejection to matched dispersion trajectory
• Asymmetric bunch merging
SPSSPSSPS
SPSSPSSPS
SPS SPS
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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(S. Hancock, M. Benedikt and J,-
L.Vallet, A proof of principle of asymmteric bunch pair merging, AB-note-2003-080 MD)
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Decay losses
• Losses during acceleration are being studied:– Full FLUKA simulations in progress for all
stages (M. Magistris and M. Silari, Parameters of radiological interest for a beta-beam decay ring, TIS-2003-017-RP-TN)
– 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
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Decay losses
• Acceleration losses:
6He(T1/2=0.8 s)
18Ne(T1/2=1.67 s)
Accumulation
<47 mW/m
<2.9 mW/m
PS 1.2 W/m 90 mW/m
SPS 0.41 W/m 32 mW/m
Decay ring 8.9 W/m 0.6 W/m
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 decaying particles to minimize peak power density in superconductor– The losses have been
simulated and one possible dipole design has been proposed
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, Radius=300 m, Straight sections=2500 m
• Magnet cost: First estimate at 100 MCHF
FLUKA simulated losses in surrounding rock (no public health implications)
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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 -decay losses accounted for, add efficiency losses (50%)
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CERN to FREJUS
Geneve
Italy
130km
40kt400kt
CERN
SPL @ CERN2.2GeV, 50Hz, 2.3x1014p/pulse 4MWNow under R&D phase
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THE PROPOSAL
C. Volpe, hep-ph/0303222To appear in Journ. Phys. G. 30(2004)L1
PHYSICS POTENTIAL
Neutrino-nucleus interaction studies for particle,nuclear physics, astrophysics (nucleosynthesis).
eeC N
Neutrino properties, like magnetic moment.
LOW-ENERGY BETA-BEAMS
boost
6HeBeta-beam
To exploit the beta-beam concept to produce intense and pure low-energy neutrino beams.
A „BETA-BEAM“ FACILITY FOR LOW-ENERGY NEUTRINOS.
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Prospects for the neutrino magnetic moment
G.C. McLaughlin and C. Volpe, hep-ph/0303222, to appear in Phys. Lett. B.
10-11 B
5 X 10-11 B
e-e events with beta-beams (10 15 /s) with a 4 low threshold detector.
6He 6Li+e+e QMeV
eee
eE
T
PRESENT LIMIT : < 1.0 x 10-10 B.
6He
THE LIMIT CAN BE IMPROVED BY ONE ORDER of MAGNITUDE (a few x 10-11 B) .
=0
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Neutrino-nucleus Interaction Rates
At a Low-energy Beta-beam Facility
J. Serreau and C. Volpe, hep-ph/0403293, submitted to Phys. Rev. D.
Small RingLarge Ring
2577982645103707 7922
94531956
e + 208Pb
e + Nucleus
e + 16O
e + D
Events/year for =14
Small Ring : Lss = 150 m, Ltot = 450 m.Large Ring :Lss = 2.5 km, Ltot = 7.5 km
Neutrino Fluxes
INTERESTING INTERACTION RATES CAN BE OBTAINED.
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Possible sites
CERN
GANIL
(EURISOL)
GSI
Intensities Detectors1012 /s 1 4
1013 /s 1-100
109 /s 1-10 4andClosedetector
4andClosedetector
Autin et al,J.Phys. (2003).
H. Weick (GSI)
A. Villari (GANIL)
CERN IS A UNIQUE SITE BOTH FOR THE -INTENSITIES AND THE -ENERGIES.
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R&D (improvements)
• Production of RIB (intensity)– Simulations (GEANT, FLUKA)– Target design, only 200 kW primary proton beam in present design
• Acceleration (cost)– FFAG versa linac/storage ring/RCS– High gamma option
• Tracking studies (intensity)– Loss management
• Superconducting dipoles ( of neutrinos)– Pulsed for new PS/SPS (GSI FAIR)– High field dipoles for decay ring to reduce arc length– Radiation hardness (Super FRS)
SPLISOL Target + ECR
Linac, cyclotron or FFAG
Rapidcycling
synchrotronPS SPS
Decay ring
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Comments & speculations:Ne and He in decay ring simultaneously
• Possible gain in counting time and reduction of systematic errors– Cycle time for each ion type doubles!
• Requiring =(60)150 for He will at equal rigidity result in a =(100)250 for Ne– Physics?– Detector simulation should give “best” compromise
• Requiring equal revolution time will result in a R of 97(16) mm (=300 m)– Insertion in one straight section to compensate
HeliumNeon
Neon
Helium
HeliumNeon q
A
q
A
HeliumNeon
HeliumHelium
Helium
NeonHeliumNeon
SSSS
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Comments & sepculations:Accumulation Ne + He in DECAY RING
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!
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Comments & sepculations:Accumulation Ne + He before acceleration
• Base line scenario assumes accumulation of 16 bunches for one second at 300 MeV/u (PS) for both He and Ne
• Optimization assuming fixed ECR intensity (out):– Longer accumulation– SPS accumulation
Accumulation (PS or SPS)
Production and bunching (ISOL and ECR)
1 s in baseline
Number of ions constant from ECR
source
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Comments & speculations:Accumulation before acceleration
50 100 150 200
10
20
30
40
50
Number of fills
Increase of intensity
SPS: He, one fill of 1 unit of ions
every 1.2 s
SPS: Ne, one fill of 1 unit of ions
every 1.2 s
PS: Ne, one fill of 1 unit of ions every
1/16 s
PS: He one fill of 1 unit of ions every 1/16 s
5 10 15 20 25 30
5
10
15
20
25
PS Baseline
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Comments & speculations:Wasted time?
Production
PS
SPS
Decay ring
Ramp time PS
Time (s)0 8
Wasted time?
Ramp time SPS
Reset time SPS
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Comments & speculations:Higher Gamma?
• Requires either a larger bending radius or a higher magnetic field for the decay ring, the baseline circumference is 6885 m and has a bending radius () of 300 m:
• At =500 (6He) , =935 m at B=5 T• To keep the percentage of straight section the same
as the baseline the ring would become 21.4 km long• Alternatively new dipoles: =300 m at B=15.6 T • Or LHC type dipoles at B=10 T and =468 m with a
circumference of 7794 m
• Requires an upgrade of SPS or ramping of the decay ring– SPS upgrade expensive and time consuming– Ramping of decay ring requires less frequent
fills and higher total intensity
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Comments & speculations:Duty factor (or empty buckets)
• The baseline delivers a neutrino beam with an energy badly troubled by atmospheric background– Duty factor=4 10-4, 4 buckets out of
919 possible filled —› 10 ns total bunch length
– At =500 the duty factor can be increased to 10-2 (P. Hernandez), 92 buckets filled or 23 times the intensity theoretically, can that be realised?
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Comments & speculations:Electron Capture, Monochromatic beams
• Nuclei that only decay by electron capture generally have a long half-life (low Q value, <1022 keV)– Some possible candidates: 110Sn (4.1 h half
life) and 164Yb (75.8 min half life)– Maybe possible if very high intensities can
be collected in the decay ring and a high duty factor can be accepted (0.1)
• High gamma with ramping of the decay ring?• For the baseline: With =259, assuming 2.3 1016
ions in the decay ring and a duty factor of 0.1 there would be 4 109 neutrinos per second at 259x0.326 MeV=84.434 MeV, is that useful?
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Design Study
EURISOLBeta-beam Coordination
Beta-beam parameter group Above 100 MeV/u
Targets60 GHz ECR
Low energy beta-beamAnd many more…
USERSFrejus
Gran SassoHigh GammaAstro-Physics
Nuclear Physics(, intensity and
duty factor)
OTHER LABSTRIUMF
FFAGTracking
CollimatorsUS studyNeutrino
Factory DS
Conceptual Design # with price ### M€
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Superbeam & Beta Beam cost estimates (NUFACT02)
Educated guess on possible costs USD/CHF 1.60UNO 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
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boost
6HeBeta-beam
“The chances of a neutrino actually hitting something as it travels through all this emptiness are roughly comparable to that of dropping a ball bearing from a cruising 747* and hitting, say an egg sandwich”, Douglas Adams, Mostly Harmless, Chapter 3
*) European A380, Prototype will fly in 2005
EURISOL Design Study, when will the beta-beam fly?
• A boost for radioactive nuclear beams
• A boost for neutrino physics
A EURISOL/beta-beam facility at CERN!