Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 1

BETA-BEAM R&D in EUROPE

Michael Benedikt AB Department, CERN

on behalf of the Beta-Beam Study Group

http://cern.ch/beta-beam/

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 2

Outline

• Beta-beam baseline design– The baseline scenario, ion choice, main

parameters– Ion production– Decay ring design issues

• Ongoing work and recent results– Asymmetric bunch merging for stacking in

the decay ring– Decay ring optics design & injection

• Future R&D within EURISOL – The EURISOL Design Study– The Beta-beam Task

• Conclusions

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 3

Introduction to Beta-beams

• Beta-beam proposal by Piero Zucchelli:– A novel concept for a neutrino factory: the beta-

beam, Phys. Let. B, 532 (2002) 166-172.

• AIM: production of pure beams of electron neutrinos (or antineutrinos) from the beta decay of radioactive ions, circulating in a high energy decay ring (~100)

• The baseline 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

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 4

Beta-beam baseline design

Neutrino Source

Decay Ring

Ion production ISOL target &

Ion source

Proton Driver SPL

Decay ring

B = 1500 Tm B = 5 T C = 7000 m Lss = 2500 m

6He: = 150 18Ne: = 60

SPS

Acceleration to medium energy

RCS

PS

Acceleration to final energy

PS & SPS

Experiment

Ion acceleration Linac

Beam preparation ECR pulsed

Ion production Acceleration Neutrino source

,

,

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 5

Main parameters (1)

• Ion choice– Possibility to produce reasonable amounts of ions– Noble gases preferred - simple diffusion out of target, gas

phase at room temperature– Not too short half-life to get reasonable intensities– Not too long half-life as otherwise no decay at high energy– Avoid potentially dangerous and long-lived decay products

• Best compromise– 6Helium2+ to produce antineutrinos:

– 18Neon10+ to produce neutrinos:

MeV 86.1 Average

MeV 937.1 Average

189

1810

63

62

cms

cms

E

eFeNe

E

eLiHe

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 6

Main parameters (2)

• Target values in the decay ring

18Neon10+ (single target)– Intensity (av.): 4.5x1012

ions – Energy: 55

GeV/u– Rel. gamma: 60– Rigidity: 335 Tm

6Helium2+

– Intensity (av.): 1.0x1014 ions

– Energy: 139 GeV/u

– Rel. gamma: 150– Rigidity: 1500 Tm

• The neutrino beam at the experiment has the “time stamp” of the circulating beam in the decay ring.

• The beam has to be concentrated in as few and as short bunches as possible to maximize the peak number of ions/nanosecond (background suppression).

• Aim for a duty factor of 10-4 -> this is a major design challenge!

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 7

Ion production - ISOL method

• Isotope Separation OnLine method.• Few GeV proton beam onto fixed target.

1 GeV protons

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

Target

18Ne directly

6He via spallation n

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 8

6He production from

9Be(n,)

• Converter technology preferred to direct irradiation (heat transfer and efficient cooling allows higher power compared to insulating BeO).

• 6He production rate is ~2x1013 ions/s (dc) for ~200 kW on target.

Converter technology: (J. Nolen, NPA 701 (2002) 312c)

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 9

18Ne production

• Spallation of close-by target nuclides:18Ne from MgO:

– 24Mg12 (p, p3 n4) 18Ne10

– Direct target: no converter technology can be used,

the beam hits directly the oxide target.

– Production rate for 18Ne is ~ 1x1012 ions/s

(200 kW dc proton beam at a few GeV beam

energy).

– 19Ne can be produced with one order of magnitude

higher intensity but the half life is 17 seconds!

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 10

From dc ions to very short

bunches

1 s

2.2 s

tB 1 s

t

B

PS

SPS

2.2 s

tB 1 s

PS

t

2 x 1.1 s to decay ring (4 bunches with few ns)

PS: 1s flat bottom with 8 (16) injections. Acceleration in ~1s to top PS energy

Target: dc production during 1 s.

60 GHz ECR: accumulation for 1/8 (1/16) s ejection of fully stripped ~20s pulse. 16 batches during 1s.

RCS: further bunching to ~100 ns Acceleration to ~300 MeV/u. 8 (16) repetitions over 1s.

SPS: injection of 8 (16) bunches from PS. Acceleration to decay ring energy and ejection of 4 + 4 bunches. Repetition time 8 s.

1 s 7 s

Post accelerator linac: acceleration to ~100 MeV/u. 8 (16) repetitions over 1s.

t

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 11

Decay ring design aspects

• The ions have to be concentrated in very few very short bunches.– Suppression of atmospheric background via time structure.

• There is an absolute need for stacking in the decay ring.

– Not enough flux from source and injection chain.

– Life time is an order of magnitude larger than injector cycling (120 s as compared to 8 s SPS cycling).

– We need to stack at least over 10 to 15 injector cycles.

• Cooling is not an option for the stacking process:

– Electron cooling is excluded because of the high electron beam energy and in any case far too long cooling times.

– Stochastic cooling is excluded by the high bunch intensities.

• Stacking without cooling creates “conflicts” with Liouville.

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 12

Asymmetric bunch pair

merging

• Moves the fresh bunch into the centre of the stack and pushes less dense phase space areas to larger amplitudes until these are cut by the momentum collimation system.

• The maximum density is always in the centre of the stack as required by the experiment.

• Requirements:

– Dual harmonic RF systems:

– Decay ring will be equipped with 40 and 80 MHz system.

– Gives required bunch lengths of < 10 ns for physics.

• Stack and fresh bunch need to be positioned in adjacent “buckets” of the dual harmonic system (12.5 ns distance!)

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 13

Full scale simulation for SPS

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 14

Test experiment in CERN PS

Merging of circulating bunch with empty phase space.

Longitudinal emittances are conserved

Negligible blow-up

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 15

Test experiment in CERN PS• Ingredients:

– Dual-harmonic RF system– 10 and 20 MHz systems of PS– Phase and voltage variations

• Potential applications:– Production of hollow bunches– Stacking in longitudinal phase space

-125 -100 -75 - 50 -25 0 25 50@nsD- 7.5

-5

- 2.5

0

2.5

5

7.5

@MeVD

0

0.1

0.2

0.3

0.4

0.5

0.6

@AD

4́014

3́014

2́014

1́014 0

@eVeD

0 5 10 15 20 25Iterations

0

8.52 ´ 1011

@esVeD

E{rms = 0.0583 eVs BF = 0.14

E{matched = 0.317 eVs Ne = 1.63 ´ 1011

2s prmsp = 1.34 ´ 10-3 fs0;1 = 0;1060 Hz

- 100 -75 - 50 -25 0 25 50 75@nsD-4

-2

0

2

4

@MeVD

0

0.1

0.2

0.3

0.4

@AD

6́014

5́014

4́014

3́014

2́014

1́014 0

@eVeD

0 10 20 30 40 50Iterations

0

8.16 ´ 1011

@esVeD

E{rms = 0.0593 eVs BF = 0.224

E{matched = 0.333 eVs Ne = 1.56 ´ 1011

2s prmsp = 8.5 ´ 10-4 fs0;1 = 0;415 Hz

-60 -40 - 20 0 20 40 60@nsD

-4

-2

0

2

4

@MeVD

0

0.1

0.2

0.3

0.4

0.5

@AD

4́014

3́014

2́014

1́014 0

@eVeD

0 5 10 15 20 25Iterations

0

8.1 ´ 1011

@esVeD

E{rms = 0.0639 eVs BF = 0.168

E{matched = 0.323 eVs Ne = 1.6 ´ 1011

2s prmsp = 1.25 ´ 10-3 fs0;1 = 823;790 Hz

-60 -40 - 20 0 20 40 60@nsD

-4

-2

0

2

4

@MeVD

0

0.1

0.2

0.3

0.4

0.5

@AD

4́014

3́014

2́014

1́014 0

@eVeD

0 5 10 15 20 25Iterations

0

8.17 ´ 1011

@esVeD

E{rms = 0.0585 eVs BF = 0.16

E{matched = 0.298 eVs Ne = 1.57 ´ 1011

2s prmsp = 1.2 ´ 10-3 fs0;1 = 822;790 Hz

time

energ

y

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 16

Decay ring injection design

aspects• Asymmetric merging requires fresh bunch injected in adjacent 2nd

harmonic bucket to existing stack

• Background suppression requires short bunches and therefore high frequency RF in decay ring ≥ 40MHz

• Combination of both means 12.5 ns between bunches

– Fast injection (septa & kickers) excluded (too fast, too rigid)

• Alternative injection scheme proposal

– Inject an off-momentum beam on matched dispersion trajectory

– No fast elements required (bumper rise and fall ~10 s)

– Requires large normalized dispersion at injection point (small beam size and large separation by momentum difference)

– Has to be paid by larger magnet apertures in decay ring

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 17

Decay ring injection layout

Septum & alignment 10 mm

Beam: ± 2 mm momentum

± 4 mm emittance

Separation: ~30 mm, corresponds to

3x10-3 off-momentum

Required bump22 mm

22 mm

Central orbit undisplaced

• Example 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 mm

Stack: ± 10mm momentum

± 4 mm emittance

Septum & alignment 10 mm

InjectionFirst turn after injection

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 18

Decay ring arc lattice design

Injection area

β-functions (m) Dispersion (m)

Begin of the arc End of the arc

Horizontal x

Vertical y

Horizontal Dispersion Dx

FODO structure

Central cells detuned for injection

Arc length ~984m

Bending 3.9 T, ~480 m leff

5 quadrupole families

A. Chance, CEA-Saclay (F)

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 19

Decay ring injection envelopes

A. Chance, CEA-Saclay (F)

septum

Envelope (m)

Horizontal envelopes :

Δp/p = 0 kickers off

Δp/p = 0 kickers on

Δp/p = 0.8% kickers off

Δp/p = 0.8% kickers on

Vertical envelopes :

stored beam

injected beam

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 20

Radiation protection - decay

losses• Losses during acceleration

– 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:– Manageable in low energy part– PS heavily activated (1s flat bottom)

• Collimation? New machine?– SPS ok.– Decay ring losses:

• Tritium and Sodium production in rock well below national limits

• Reasonable requirements for tunnel wall thickness to enable decommissioning of the tunnel and fixation of Tritium and Sodium

FLUKA simulated losses in surrounding rock (no public health implications)

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 21

Future R&D

• Future beta-beam R&D together with EURISOL project• Design Study in the 6th Framework Programme of the EU

• The EURISOL Project– Design of an ISOL type (nuclear physics) facility – Performance three orders of magnitude above existing facilities– A first feasibility / conceptual design study was done within FP5– Strong synergies with the beta-beam especially low energy part:

• Ion production (proton driver, high power targets)• Beam preparation (cleaning, ionization, bunching)• First stage acceleration (post accelerator ~100 MeV/u)• Radiation protection and safety issues

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 22

EURISOL Design Study

Production of an Engineering Oriented Design, of the facility, in particular in relation to its most technologically advanced aspect (i.e. excluding the detailed design of standard elements of the infrastructure).

• Technical Design Report for EURISOL.• Conceptual Design Report for Beta-Beam (first

study).Acronym: EURISOL DS

Requested budget: About 9 M€

Deadline for proposal: 4 March 2004

Starting date: January 2005

Duration of the project: 48 months

Coordinating Institution: GANIL, Techn. Coordinator: John Cornell

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 23

Eurisol Design Study Tasks

12 TASKS LEADER INSTITUTE * NATURE OF WORK

1) Liquid Metal Target/Ion Source H. Ravn/U. Koester CERN-PH PW - PRO - E

2) Direct Target / Ion-Source J. Lettry CERN-AB PW - PRO - E

3) Solid Converter Target / Ion–Source

L. Tecchio INFN PW - PRO – E

4) Safety & Radioprotection D. Ridikas CEA SACLAY PW

5) Heavy-Ion Accelerator Design M-H. Moscatello GANIL PW -PRO

6) Proton Accelerator Design A. Facco INFN PW - PRO

7) SC Cavity Development S. Bousson IPNO PW –PRO

8) Beam Preparation A. Jokinen JYFL PW - PRO - E

9) Physics and Instrumentation R. Page U LIVERPOOL PW - PRO

10) Beam Intensity Calculations K.H. Schmidt GSI PW – E

11) Beta Beams Aspects M. Benedikt CERN-AB PW

12) Global Coherence and Layout TO BE DEFINED

*PW=Paperwork PRO=Prototype E =Experiment

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 24

EURISOL - Participating

Institutes

PARTICIPANTS PERSON IN CHARGE

1 GANIL (F) D. GOUTTE

2 IN2P3 (F) D. GUERREAU

3 INFN-LNL (I) G. FORTUNA

4 INFN-LNS (I) E. MIGNECO

5 INFN (I) G. RICCO

6 CERN M. LINDROOS

7 UNIV.UPPSALA (S) C. EKSTROM

8 CEA (F) N. ALAMANOS

9 UNIV. FRANKFURT (G) ?

10 NIPNE (RO) D. BUCURESCU

11 JYVASKYLA (FI) R. JULIN

12 UNIV.MUECHEN (G) AUMULLER

PARTICIPANTS PERSON IN CHARGE

13 FZ JULICH (G) D. GRZONKA

14 UNIV. MAINZ (G) C. SPATH

15 IOP (LI) ?

16 UNIV. WARSAW (PL) W.MACIEJEJEWSKI

17 IOP (SK) E. BETAK

18 UNIV. SURREY (UK) LILIARD

19 UNIV. LIVERPOOL (UK) R. D. PAGE

20

GSI (G) W. HENNING

21 USDC (E) G.R. GAYOSO

22

CCLRC RAL (UK) D. WARNER

23 PSI (CH) W. FISCHER

24 UNIVERSITY HOSPITAL OF GENEVE

?

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 25

Task: Beta Beam Aspects

Neutrino

Source

Decay Ring

Ion production

ISOL target & Ion source

Proton Driver SPL

Decay ring

Br = 1500 Tm B = 5 T C = 7000 m Lss = 2500 m

6He: = 150 18Ne: = 60

SPS

Acceleration to medium energy RCS

PS

Acceleration to final energy

PS & SPS

Experiment

Ion acceleration

Linac

Beam preparation ECR pulsed

Starts at exit of heavy ion LINAC (~100 MeV/u) to Decay Ring (~100 GeV/u).

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 26

Beta-Beam Sub-

Tasks

• Beta Beam task starts at exit of the EURISOL post accelerator.

• Comprises the design of the complete chain up to the decay ring.

• Organisation: „parameter and steering committee“ and 3 sub-tasks:

– ST 1: Design of the low energy ring(s)

– ST 2: Ion acceleration scenarios in PS/SPS and required upgrades of the existing machines including new designs to eventually replace PS/SPS

– ST 3: Design of the high energy Decay Ring

– Detailed work and man-power planning is under way

– Around 38 (13 from EU) man-years for beta beam R&D over next 4 years (only within beta-beam task, not accounting linked tasks)

Osaka, 25/07/04 NuFACT’04 - Beta Beam R&D M. Benedikt 27

Conclusions

• Well established beta-beam base line scenario

• R&D work has started on several critical aspects (mainly decay ring)

• Beta-Beam Task well integrated in the EURISOL DS

• Strong synergies between Beta Beam and EURISOL

• Definitive EU decision expected these days

• Detailed planning for coming 4 years under way