1. Status of the beta-beam study
Mats Lindroos on behalf of the EURISOL beta-beam task
RAL 27 April 2006
The beta-beam task, EURISOL

2. The beta-beam task, EURISOL
Outline
The beta-beam
Progress on a conceptual design
EURISOL beta-beam facility
Challenges for the beta-beam
Conclusions
RAL 27 April 2006
The beta-beam task, EURISOL

3. The EURISOL beta-beam facility!
RAL 27 April 2006
The beta-beam task, EURISOL

4. The beta-beam task, EURISOL
Beta-beam R&D
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 low-energy part of the beta-beam:
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.
Subtasks within beta-beam task
ST 1: Design of the low-energy ring(s).
ST 2: Ion acceleration 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.
Around 38 (13 from EU) man-years for beta-beam R&D over next 4 years (only within beta-beam task, not including linked tasks).
RAL 27 April 2006
The beta-beam task, EURISOL

5. Design study objectives
Establish the limits of the first study based on existing CERN accelerators (PS and SPS)
Freeze target values for annual rate at the EURISOL beta-beam facility
Close cooperation with neutrino physics community
Freeze a baseline for the EURISOL beta-beam facility
Produce a Conceptual Design Report (CDR) for the EURISOL beta-beam facility
Produce a first cost estimate for the facility
RAL 27 April 2006
The beta-beam task, EURISOL

6. Challenges for the study
Production
Charge state distribution after ECR source
The self-imposed requirement to re-use a maximum of existing infrastructure
Cycling time, aperture limitations etc.
The small duty factor
The activation from decay losses
The high intensity ion bunches in the accelerator chain and decay ring
RAL 27 April 2006
The beta-beam task, EURISOL

7. Intensity distribution during acceleration
Bunch
20th
15th
10th
5th
1st
total
30% of first 6He bunch injected are reaching decay ring
Overall only 50% (6He) and 80% (18Ne) reach decay ring
Normalization
Single bunch intensity to maximum/bunch
Total intensity to total number accumulated in RCS
RAL 27 April 2006
The beta-beam task, EURISOL

8. Power losses - comparison
Power loss per unit circumference of a machine
Ploss/l [ions]
Beta-beam
CNGS
6He
18Ne
RCS -
0.17
0.14 PS
3.3
2.2
2.8
SPS
0.25
0.4
Nucleon losses compared
PS and SPS comparable for CNGS and bb operation
PS exposed to highest power losses
RAL 27 April 2006
The beta-beam task, EURISOL

9. The beta-beam task, EURISOL
Dynamic vacuum
Decay losses cause degradation of the vacuum due to desorption from the vacuum chamber
The current baseline includes the PS, which does not have an optimized lattice for unstable ion transport and has no collimation system
The dynamic vacuum degrades to 10-5 Pa in steady state (6He)
An optimized lattice with collimation system improves the situation by two orders of magnitude
P. Spiller et al., GSI
RAL 27 April 2006
The beta-beam task, EURISOL

10. The beta-beam task, EURISOL
Merging
S. Hancock, CERN
Achieving >90% merging efficiency of injected particles
Some ions are already collimated before having been stacked for 15 (20) merging cycles
Ionsstored/ionsinjected
t [s]
6He
merges
Ionsstored/ionsinjected
t [s]
18Ne
merges
RAL 27 April 2006
The beta-beam task, EURISOL

11. Decay ring - Momentum collimation
A. Chance et al., Saclay
After 15 (20) merges 50% (70%) of the injected 6He (18Ne) ions are pushed outside the acceptance limits.
Momentum collimation required.
Dispersion region; multi stage collimation system
Space required: placed in “unused” straight section
Collimation power corresponds
to 150 kW average
to MW peak level during the bunch compression process
compression process lasts a few hundred milliseconds
Injected/merged
collimated
decayed
He6
Ne18
LHC p+
LHC Pb 
100
7461
2964
T/ion (GeV)
555
1660
7000
574000
τrepetition (s) 6
3.6
10h
Number of stored ions
4 1010
Stored beam energy (MJ)
8.8
19.7
2 x 362
2 x 3.81
RAL 27 April 2006
The beta-beam task, EURISOL

12. Decay ring - Decay losses
Decay products originating
1) from straight section
2) in arcs
1) are extracted at the first dipole in the arc, sent to dump
2) Arc lattice optimized for absorption of decay products
To accommodate either ion species, the half-aperture has to be very large (~ 8cm for the SC dipoles).
Absorbers take major part of decay losses ion arcs.
About 60 W each
SC dipoles still have to stand <10 W/m.
aperture [cm]
Power loss [W/m]
A. Chance et al., Saclay
RAL 27 April 2006
The beta-beam task, EURISOL

13. The beta-beam task, EURISOL
Production
Major challenge for 18Ne
Workshop at LLN for production, ionization and bunching this summer
New production method proposed by C. Rubbia!
RAL 27 April 2006
The beta-beam task, EURISOL

14. The beta-beam task, EURISOL
Production ring with ionization cooling (C. Rubbia, A.Ferrari, Y.Kadi and V. Vlachoudis)
RAL 27 April 2006
The beta-beam task, EURISOL

15. The beta-beam task, EURISOL
Ionization cooling
RAL 27 April 2006
The beta-beam task, EURISOL

16. The beta-beam task, EURISOL
Using existing PS and SPS, version 2 Space charge limitations at the “right flux”
Transverse emittance normalized to PS acceptance at injection for an annual rate of 1018 (anti-) neutrinos
Space charge tune shift
Note that for LHC the corresponding values are and -0.34
RAL 27 April 2006
The beta-beam task, EURISOL

17. The slow cycling time. What can we do?
Ramp time PS
Reset time SPS
Ramp time SPS
Decay ring
SPS PS
Production
Wasted time? 8
Time (s)
RAL 27 April 2006
The beta-beam task, EURISOL

18. The beta-beam task, EURISOL
Accumulation at 400 MeV/u
T1/2=1.67 s
T1/2=17 s
T1/2=0.67 s
RAL 27 April 2006
The beta-beam task, EURISOL

19. The beta-beam task, EURISOL
Stacking
Multiturn injection with electron cooling
RAL 27 April 2006
The beta-beam task, EURISOL

20. The beta-beam task, EURISOL
150Dy
Partly stripped ions: The loss due to stripping smaller than 5% per minute in the decay ring
Possible to produce Dy atoms/second (1+) with 50 microAmps proton beam with existing technology (TRIUMF)
An annual rate of 1018 decays along one straight section seems as a realistic target value for a design study
Beyond EURISOL DS: Who will do the design?
Is 150Dy the best isotope?
RAL 27 April 2006
The beta-beam task, EURISOL

21. Long half life – high intensities
At a rate of 1018 neutrinos using the EURISOL beta-beam facility:
RAL 27 April 2006
The beta-beam task, EURISOL

22. Gamma and decay-ring size, 6He
Rigidity
[Tm]
Ring length
T=5 T
f=0.36
Dipole Field
rho=300 m
Length=6885m
100
938
4916
3.1
150
1404
6421
4.7
200
1867
7917
6.2
350
3277
12474
10.9
500
4678
17000
15.6
New SPS
Civil engineering
Magnet R&D
RAL 27 April 2006
The beta-beam task, EURISOL

23. The beta-beam task, EURISOL
In 2008 we should know
The EURISOL design study will with the very limited resources available give us:
A feasibility study of the CERN-Frejus baseline
A first idea of the total cost
An idea of how we can go beyond the baseline
Resources and time required for R&D
Focus of the R&D effort
Production, Magnets etc.
RAL 27 April 2006
The beta-beam task, EURISOL