AB seminarBENE beta-beam network The Beta-beam Mats Lindroos on behalf of the The BENE beta-beam network

AB seminar BENE beta-beam network

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

Mats Lindroos on behalf of the

The BENE beta-beam network


Collaborators• BENE beta-beam network:

– GSI: • Helmuth Weick, Markus Steck, Peter Spiller, Oliver Boine-Frankenheim, R. Hollinger, B. Franzke

– CEA:• Olivier NAPOLY, Jacques Payet, Jacques Bouchez

– IN2P3:• Cristina Volpe, Alex Muelle, Pascal Sortais, Laune Bernard, Antonio Villar

– INFN:• Vittorio Palladino, Mauro Mezzetto, Alberto Facco, Andrea Pisent

– UK:• Chris Prior, Marielle Chartier

– CERN:• Mats Lindroos, Steven Hancock, Matteo Magistris, Simone Gilardoni, Fredrik Wenander, Roland

Garoby, Michael Benedikt, Ulli Koester

– Geneva University:• Alain Blondel

– Louvain-la-neuve:• Guido Ryckewaert, Thierry Delbar

– Uppsala:• Dag Reistad

– Associate:• Andreas Jansson, Rick Baartman


Acknowledgements

• For kindly having assisted with this specific presentation:– M.Benedikt, A.Blondel, J.Bouchez,

K.Elsener, S.Gilardoni, R.Garoby, S.Hancock, A.Jansson, U.Koester M.Magistris, S.Russenschuck, P.Sortais, C.Volpe, F.Wenander


Outline

• Neutrino oscillations• The beta-beam

– Overview– The CERN base line scenario

– The Moriond workshop

• The super beam• Conclusions


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


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


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


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


Desired beam parameters in the decay ring

18Neon10+

– Intensity: 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.

• We need to concentrate the beam in as few and as short bunches as possible to maximize the number of ions/nanosecond. (background suppression)

• Clearly 6He is the more demanding ion and considered further on .

6Helium2+

– Intensity: 1.0x1014 ions – Energy: 139

GeV/u– Rel. gamma: 150– Rigidity: 1500 Tm


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


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)


Mercury jet converter

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


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


extraction

target

ECR volume

~250 mm

ISOECRIS• based on a ISOLDE unit • coils• consumable unit• in production

target side

extraction side

~250 mm

MINIMONO ISOLDE• GANIL design [1,2]• ‘standard’ ISOLDE unit• permanent magnets• consumable unit• on-line test 2003

MONOECR (at ISOLDE)MONOECR (at ISOLDE)

F. Wenander, J.Lettry


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


Low-energy stage

Objective:• Fast acceleration of ions and

injection• Acceleration of 16 batches to 20

MeV/u



Rapidcycling

synchrotronPS SPS

Decay ring


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


Overview: Accumulation

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


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


SPS

Overview:PS to SPS

• Merging in PS to 8 buckets• Blow-up before transfer to manage

space charge limit in SPS

PSPSPSPS

SPS

PS


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


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


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.


SPS

Overview: Decay ring

• Ejection to matched dispersion trajectory

• Asymmetric bunch merging

SPSSPS


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


Injection to decay ring

M. Benedikt


Asymmetric bunch merging

S. Hancock


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.


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


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.


SC magnets• Dipoles can be

built with no coils in the path of the decay (one ion type) particles to minimise peak power density in superconductor (quench stability).

S. Russenschuck, CERN


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

ShieldingTunnel

Arc cross-section

CERN CERN Cricket Cricket ClubClub


Intensities: 6He

• From ECR source: 2.0x1013 ions per second• Storage ring: 1.0x1012 ions per bunch• Fast cycling synch: 1.0x1012 ion per bunch• PS after acceleration: 1.0x1013 ions per batch• SPS after acceleration:0.9x1013 ions per batch• Decay ring: 2.0x1014 ions in four 10

ns long bunch– Only -decay losses accounted for, efficiency <50%


Intensities: 18Ne

• From ECR source: 0.8x1011 ions per second• Storage ring: 4.1x1010 ions per bunch• Fast cycling synch: 4.1x1010 ion per bunch• PS after acceleration: 5.2x1011 ions per batch• SPS after acceleration:4.9x1011 ions per batch• Decay ring: 9.1x1012 ions in four 10

ns long bunch– Only -decay losses accounted for, efficiency <50%


Moriond meeting• Annual electro week meeting in Les Arcs• Workshop on Radioactive beams for

Nuclear and Neutrino Physics– Organizer: Jacques Bouchez, CEA, Saclay

• Many new ideas, among them:– Multiple targets for Ne production– ECR bunching (P. Sortais)– Ne and He in the decay ring simultaneously– Low energy beta facility (C. Volpe)

• GSI, GANIL and CERN (in close detector)


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?– Detector simulation should give “best”

compromise

• Requiring equal revolution time will result in a R of 20 mm (R0=1090 m)– Manageable?


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!


CERN to FREJUSGeneve

Italy

130km

40kt400kt

CERN

SPL @ CERN2.2GeV, 50Hz, 2.3x1014p/pulse 4MWNow under R&D phase


The Super Beam


HERE : 250 MeV NEUTRINOS


Water CherenkowSuper Kamiokande

MultiUSER detector: Astrophysics, Beta-beam, Super Beam, Proton Decay


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


SPL (8 MW) for many users

15 ms accelerated to 2.2 GeVfor other Users

3ms2.2 GeV

for NuFact and Super Beam

20 ms

15 mA

3 mA

total power at 2.2 GeV 4 MW X 2 = 8 MW

beam


Physics reach

M. Mezzetto


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


Conclusions• Physics:

– Strong interest from community– Super beam, beta-beam and FREJUS: WORLD unique– Low energy beta-beam: other sites

• A baseline scenario 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!– Higher intensity in the decay ring– First results are so encouraging that the beta-beam

option should be fully explored


Open questions…

…among them• Target (area) design

– EURISOL study (Design study in 6th EU FP)• Efficiency of ECR chargebreeding and bunching• Low energy acceleration

– LINAC/ECR/FFAG?• Combined storage ring and Rapid Cycling Synchrotron• Injection into Rapid Cycling Synchrotron• PS – do we need a new (Rapid cycling) machine?• Space charge bottle neck from PS to SPS• Lattice for decay ring

– Many constraints if Ne and He should be stored simultaneously• Stability of short high intensity ion bunches in decay ring• Magnet design for decay ring• Civil engineering of decay ring

– Shielding issues to avoid groundwater activation


Comment• We are all working hard to complete the

LHC and to keep CERN running…• In your already overloaded week try to

find 2 hours…– Spend one of these hours on our future

• CLIC• Nufact• Beta-beam• And many more ideas

– Spend the other hour on LHC• The succesfull completion of LHC is conditional for

any long term future of CERN

• Thank you for your attention!

Documents

AB seminarBENE beta-beam network The Beta-beam Mats Lindroos on behalf of the The BENE beta-beam network