Benasque The Beta-beam Mats Lindroos on behalf of The beta-beam study group

Benasque

The Beta-beamhttp://cern.ch/beta-beam

Mats Lindroos on behalf of

The beta-beam study group

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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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Mercury jet converter

H.Ravn, U.Koester, J.Lettry, S.Gardoni, A.Fabich

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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



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?



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



Fast cycling

synchrotronPS SPS

Decay ring

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Overview: Accumulation

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



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



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

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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

8.1 1011

esVe

rms 0.0639 eVs BF 0.168


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

8.52 1011

esVe

rms 0.0583 eVs BF 0.14


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


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 Super Beam

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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)



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!

Documents

Benasque The Beta-beam Mats Lindroos on behalf of The beta-beam study group