1. The beta-beam project in the EURISOL context
Pierre Delahaye, ISOLDE / CERN
for the beta-beam working group
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

2. Pierre Delahaye, Quantum seminar, Mainz
The physics reach
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

3. About neutrino physics
The neutrino: a mass-less particle to explain the continuous energy spectrum of the beta decay. Wolfgang Pauli 1930.
Only left-handed neutrinos can interact with matter. V-A theory 1958.
Majorana or Dirac neutrinos?
3 flavors ne, nm, nt
A mass is an interaction between flavors
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

4. The flavor mixing matrix
The mass eigenstates are not flavor eigenstates
3 angles + 1 CP violating phase for Dirac neutrinos
In analogy with the CKM matrix:
The Maki-Nakagawa-Sakata matrix
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

5. Oscillation of neutrinos
A simplified case (2 families)
|ne> = cos |n1> + sin  |n2>
|nm> = – sin |n1> + cos  |n2>
|n(t=0)> = |ne>
|n(t)> = exp(-iE1t) cos |n1> + exp(-iE2t) sin |n2>
P(ne –>nm) = |<nm|n(t)>|2 = sin22 sin2 (Dm2/4E t)
Dm 2 = m12 –m22
L osc (m) = 2.5 En (MeV) / Dm2(eV2)
A measurement of q and Dm²
E. Kh. Akhmedov†
hep-ph/
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

6. Oscillation of neutrinos
Current status
SUN : Dm122 = eV2 , 12~ 35o
ATM : Dm232 = eV2 , 23 = 45o
Missing
13 and the phase d
both govern the nm  ne oscillation at the atmospheric frequency. We know that 13 (Chooz) is < 13o
The hierarchy of the masses
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

7. Pierre Delahaye, Quantum seminar, Mainz
Overview
Neutrino mixing matrix
The mass hierarchy
OR?
Dm223= eV2
Dm212= eV2 n1 n2 n3
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

8. Pierre Delahaye, Quantum seminar, Mainz
The beta-beam concept
P. Zucchelli, PLB 2002
A pure beam of ne to study the nenm oscillation
A beam of ne, ne from b-decaying nuclides
A Lorentz boost for a collimated beam (high g)
From Wikipedia:
For a boost in an arbitrary direction with velocity , it is convenient to decompose the spatial vector into components perpendicular and parallel to the velocity : … . Then only the component in the direction of is 'warped' by the gamma factor:
where now
q1/g
Lorentz boost q
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

9. Possible synergy with superbeams
Neutrino experiments :
Measurement of the mixing angle
Study of CP violation
e  m (+) m  e (p+)
e  m (-) m  e (p-) CP T
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

10. The CERN baseline scenario
Using the existing infrastructure
+ an upgrade of the proton driver “the SPL”
+ a new preparation stage
+ a decay ring (g>100)
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

11. A beta-beam and… its detector
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

12. Pierre Delahaye, Quantum seminar, Mainz
In more details
From J. Bouchez
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

13. What b-decaying nuclides?
Factors influencing ion choice
Need to produce reasonable amounts of ions.
Noble gases preferred - simple diffusion out of target, gaseous 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
Helium-6 to produce antineutrinos:
Neon-18 to produce neutrinos:
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

14. Pierre Delahaye, Quantum seminar, Mainz
The requirements
The first study “Beta-beam” was aiming for:
A beta-beam facility that will run for a “normalized” year of 107 seconds
An annual rate of anti-neutrinos (6He) and neutrinos (18Ne) at g=100
with an Ion production in the target to the ECR source:
6He= atoms per second
18Ne= atoms per second
The often quoted beta-beam facility flux for ten years running is:
Anti-neutrinos: decays along one straight section
Neutrinos: decays along one straight section
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

15. Pierre Delahaye, Quantum seminar, Mainz
Physics potential
Measurement of the q13 and dCP angles
dCP as low as 20°, q13 as low as 1°
M. Mezzetto, Nucl. Phys. 143, (2005).
M. Mezzetto, Talk at NUFACT05,
June 2005, Rome.
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

16. Potential with a low energy beta-beam
Neutrino-nucleus interaction cross sections poorly known
Of interest for nuclear structure and astrophysics (nucleosynthesis)
Improving the limits on the magnetic moment of the neutrino
Improving the limit by one order of magnitude. Current limit from reactor experiments (MUNU, Kuo-Sheng, Rovno,…)
Some interest for neutrinoless double b-decay
Populating the states of many virtual transitions involved in the neutrino-less double-beta decay, for constraining the predictions on the half-lives.
C. Volpe, Nucl. Phys. A 752(2005) 38c-41c
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

17. A dedicated storage ring
A first calculation has shown that a small devoted
storage ring is more appropriate for such applications.
Serreau and Volpe, PRC 70 (2004) hep-ph/
close
detector n
Injection from PS and SPS is needed (to reach g=7-14)
for both 6He and 18Ne Lindroos and Benedikt
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

18. The facility overview accelerators and storage ring
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

19. Pierre Delahaye, Quantum seminar, Mainz
Beam specifications
The atmospheric neutrino background is large at 500 MeV, the detector can only be open for a short moment every second
The decay products move with the ion bunch which results in a bunched neutrino beam
Low duty cycle – short and few bunches in decay ring
Accumulation to make use of as many decaying ions as possible from each acceleration cycle
Ions move almost at the speed of light
Only “open” when neutrinos arrive
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

20. Facility overview Low-energy part High-energy part Ion production
Acceleration
Neutrino source
Beam to experiment
Proton Driver SPL
Acceleration to final energy
PS & SPS
Ion production ISOL target & Ion source
SPS
Decay ring
Br = 1500 Tm B = ~5 T C = ~7000 m Lss= ~2500 m
6He: g = Ne: g = 100
Neutrino Source
Decay Ring
Beam preparation ECR pulsed
Ion acceleration Linac PS
Acceleration to medium energy RCS
Existing!
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

21. Pierre Delahaye, Quantum seminar, Mainz
SPS cycle structure
M. Benedikt, S. Hancock and M. Lindroos, Proceedings of EPAC 2004
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

22. Stacking in the decay ring
Ions in short bunches to reduce the background from the atmospheric neutrinos
Stacking in the decay ring necessary because
Not enough flux from the ion source
The half-life 120s is much longer than the SPS cycle (8s).
Need to stack for at least injector cycles
The electron cooling for such an energy and long cycle time is excluded. The stochastic cooling is excluded because of the bunch intensity.
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

23. Asymmetric bunch pair merging
Moves a fresh dense bunch into the core of the much larger stack and pushes less dense phase space areas to larger amplitudes until these are cut by the momentum collimation system.
Central density is increased with minimal emittance dilution.
Requirements:
Dual harmonic rf system. The decay ring will be equipped with 40 and 80 MHz systems (to give required bunch length of ~10 ns for physics).
Incoming bunch needs to be positioned in adjacent rf “bucket” to the stack (i.e., ~10 ns separation!).
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

24. Simulation (in the SPS)
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

25. Test experiment in CERN PS
Ingredients
h=8 and h=16 systems of PS.
Phase and voltage variations.
time
energy
S. Hancock, M. Benedikt and J-L.Vallet, A proof of principle of asymmetric bunch pair merging, AB-Note MD
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

26. Pierre Delahaye, Quantum seminar, Mainz
Decay ring parameters
J. Payet and A. Chancé, CEA Dapnia/Saclay
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

27. Pierre Delahaye, Quantum seminar, Mainz
Decay ring optics
Beam envelopes
In the straight sections, we use FODO cells. The quadripoles are not superconducting and are 1 m long
The arc is a 2 insertion composed of regular cells and an insertion for the injection
There are 489 m of 6 T bends with a 5 cm half-aperture
At the injection, the dispersion is m while the horizontal beta function is as 21.2 m
The injection magnet septum is 18 m long with a 1 T field
Arc optics
J. Payet and A. Chancé, CEA Dapnia/Saclay
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

28. Synergies with EURISOL and radioactive ion beam production
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

29. The chart of the nuclides An open landscape for investigations
Nuclear physics
Structure, magic numbers, deformations, haloes, Superheavy elements, nuclear equation of states…
Nuclear Astrophysics
Nucleosynthesis, r and rp processes, supernovae explosions, X ray bursts…
Weak Interaction physics and fundamental symmetries
CVC, CKM Unitarity, Exotic interactions…
Solid State physics
&
Medical Applications!
From the EURISOL report
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

30. Pierre Delahaye, Quantum seminar, Mainz
EURISOL
An ISOL-type facility
A next generation facility for:
High intensities
More exotic beams
High beam purity
High beam quality
More energies
More users …
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

31. Pierre Delahaye, Quantum seminar, Mainz
ISOL and In-flight
ISOLDE, GANIL/SPIRAL, TRIUMF, …
GSI (FAIR project), MSU, ANL…
From the EURISOL report
ISOL: Such an instrument is essentially a target, ion source and an electromagnetic mass analyzer coupled in series. H. Ravn and B.Allardyce, 1989, Treatise on heavy ion science
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

32. 6He production from 9Be(n,a)
Converter technology: (J. Nolen, NPA 701 (2002) 312c)
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.
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

33. Pierre Delahaye, Quantum seminar, Mainz
The 18Ne case
Spallation reaction in a MgO target, 1m long with 2.2 GeV protons from the SPL
At most /s instead of the /s required!!
19Ne instead? M. Loiselet, Louvain La Neuve
An production ring with ionization cooling?
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

34. A production ring with ionization cooling?
C. Rubbia, A.Ferrari, Y.Kadi and V. Vlachoudis
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

35. Pierre Delahaye, Quantum seminar, Mainz
Some tests at LLN
Work within EURISOL task 2 to investigate production rate with “medical cyclotron”
Louvain-La-Neuve, M. Loiselet
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

36. The production of the short bunches
For the injection into the RCS
Fully stripped radioactive ions at 100 MeV/u (from the superconducting linac)
Bunches of less than 50ms
An ECR ion source (60GHz) for pulses of high peak current 12mA and short bunches 50ms
Emittance ≤ 50p.mm.mrad
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

37. Pierre Delahaye, Quantum seminar, Mainz
Tests at LPSC Grenoble
Klystron
2 GHz
(not visible)
Gyrotron
1O GHz
Available for the PreGlow Study
Diagnostics
PHOENIX
ECR Source
60 kV Platform
New LPSC Lab
T. Lamy and T. Thuillier
90° Bending Magnet
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

38. Preglow and afterglow modes
The preglow and afterglow modes are the pulsed modes of the ECR. Only scarce data exists on the preglow mode.
t (ms)
Iht (mA)
Puhf (KW)
p (mbar)
~ 10 mA / 1 ms some ions
10 ms / 10 Hz
10-6 mbar
Some 10-6 mbar / 2 liters plasma chamber / some 1013 atoms
Pumping effect during the preglow - of high interest!
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

39. Phoenix 28GHz preliminary results
u.a.
Low pressure
Discharge
i.e.
low density
without MCI
Pre glow
with MCI H+
H2+
Ar9+
Ar8+
Ar4+
Ar2+
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz
T. Lamy and T. Thuillier

40. Scaling with the frequency
1ms, 10mA pulses were obtained with the 28GHz source
The pulses have to be shortened to 50ms
A 70GHz gyrotron might be used for first tests in Nizhniy Novgorod (V. Zorin) with a magnetic confinement structure still to be defined
Special ion optics for the extraction and injection of the high intensity pulses will need to be designed
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

41. Pierre Delahaye, Quantum seminar, Mainz
Conclusion
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

42. Pierre Delahaye, Quantum seminar, Mainz
Status
Rather complete studies for the accelerator and storage rings have been started.
Not mentionned here: decay losses and space charge studies
The production and charge breeding of such an intense beam of 18Ne might be a limitation.
Some alternative solutions have been proposed (19Ne and Carlo Rubbia scenario)
Some progresses with ISOL target and ion sources can be expected in such a timescale
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

43. A project open for new propositions!
Numerous physics cases, under investigation
Numerous technical challenges
The enlargement of the community is desirable, participation is welcome
Timescale: not before 2012
So it is not too late for any suggestion!
Thanks a lot for your attention!
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz

44. The beta-beam project web-site
Members, presentations, progress reports:
Special thanks to Mats Lindroos ISOLDE, CERN for his kind help
6/8/2006
Pierre Delahaye, Quantum seminar, Mainz