rnb 6the beta-beam study group the beta-beam thomas nilsson and mats lindroos on behalf of the the...

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


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


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


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


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


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 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?



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



Rapid cycling

synchrotronPS SPS

Decay ring


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



Rapidcycling

synchrotronPS SPS

Decay ring


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.


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


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


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


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


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


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%)


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)


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


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


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


Physics reach: CP-violation

M. Mezzetto


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


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

[email protected])

rnb 6the beta-beam study group the beta-beam thomas nilsson and mats lindroos on behalf of the the...

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