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J. BouchezCEA/DAPNIA
CHIPP NeuchâtelJune 21, 2004
A NEW UNDERGROUND LABORATORY AT FREJUSMotivations and prospects
EDELWEISS II Set up
Paraffin
GeLead
He
NEMO 3PRESENT EXPERIMENTS
0 1000 2000 3000
040002000 6000 8000
102
103
104
105
106
IMB
SOUDAN
CANFRANC
KAMIOKA
BOULBY MINE
GRAN SASSO
HOMESTAKE LSM
BAKSAN MONT BLANC
SUDBURY
Depth (meters)
Depth (meters of water equivalent)
(FINLANDE)
ST GOTHARD
(WIPP)
muon flux per m2 and per year
( FRÉJUS )
4800
13 km (12 870 m)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 2122 232425262728293031323334
70m x 70m x 250m
France Italy
Future Lab.
Present road Tunnel at Fréjus (grey)andfuture Tunnel (black) for safety with 34 bypasses (shelters)connecting the two Tunnels
Components of the Project
-> a very large Laboratory to allow the installation of a Megaton-scale Cerenkov Detector ( ≈ 10 6 m3) and/or a Liquid-Argon Detector
Present Tunnel
Future Safety Tunnel
Present Laboratory
Future Laboratory with Water Cerenkov Detectors
How to overcome superbeam limitations ?
Main problem :
SPL protons produce less negative pions, so less antineutrinos
antineutrino cross-section ~ 5 times smaller than neutrinos
So 10 SPL years have to be shared as ~ 2 neutrino + 8 antineutrino years
The solution :
Produce a e beam to study e oscillation and run it SIMULTANEOUSLY
with beam from SPL
Compare e and e (T asymetry, equivalent to CP asymetry)
THIS WAS THE INITIAL MOTIVATION FOR A BETA BEAM
BETA BEAMSConcept proposed by Piero Zucchelli
•Produce radioactive ions (ISOL technique)•Accelerate them in the CERN accelerator complex up to of order 100• Store ions in a storage ring with long straight sections aimed at a far detector
Advantages
•strongly focussed neutrino beam due to small Q value of beta decays (quality factor /Q)• very pure flavour composition ( contamination ~ 10 -4 )•perfectly known energy spectrum
Baseline scenario studied at CERN (Mats Lindroos and collaborators)
Possible synergy between beta beams and EURISOL (Moriond workshop)
Updated study of expected performances (Mauro Mezzetto)
Intensities (original design)Stage 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%)
baseline scenario updated for new conditions:
• simultaneous running of He6 and Ne18
• new values of gamma factors
• 3 Eurisol targets for Ne18
antineutrino flux from He6 ( γ=60) 1.15 1011/second
neutrino flux from Ne18 ( γ=100) 0.18 1011/second
How to improve the fluxes ?
R&D on ISOL targets
Increase ion collection time (factor 1.5 to 2)
Flat bottom in the SPS (factor 1.5)
Faster PS (factor 2 or more due to less transmission losses)
Improvement factors of 5 or more seem realistic
For the sensitivity studies, improvement factors of 2.8 for He6 and 6.3 for Ne18 have been chosen.
These numbers will be refined (among others) in the new version of the baseline scenario within 1 year
antineutrino flux from He6 ( γ=60) 2.9 1011/second
neutrino flux from Ne18 ( γ=100) 1.1 1011/second
Performances of super + beta beams
Working hypotheses (Mauro Mezzetto):
• Announced intensities for e and antie (with 3 ISOL targets for Neon)
•UNO-like detector installed at a new Frejus underground laboratory•10 years running of both SPL and beta beam: - 2 years of
- 8 years of anti
- 10 years of e
- 10 years of anti e
Since 18 Ne and 6 He ions do not have the same rigidity, the anti e
energy will be 1.67 times the e energy
THIS NEEDS TUNING TO FIND THE BEST COMPROMISE
Lorentz boost optimization : Preferred values between = 55 and 75
Rates for 4400 kT.years
• cc evts (no osc, nocuts) 19710 144784 36698 23320• oscillated at Chooz limit 612 5130 1279 774 • total oscillated (δ=900, =30) 44 529 93 82• δ term -9 57 -20 12 • beam background 0 0 140 101• detector background 1 397 37 50
beta beam superbeam
He6 Ne18 νμ anti ν
γ=60 γ=100 2 y 8 y
13 sensitivity (δ=0) after 5 years (Minos 2 years) 90%CL
and measurements using superbeam and betabeam
SPL:
2 years in + 8 years in anti
BETABEAM:
10 years of 6He AND 18Ne
(Mauro Mezzetto)
90%CL sensitivity after 5 years (Superbeams νμ only)
99%CL sensitivity to maximal CP violation after 10 years
(SPL-SB 2 years + 8 years)
3 σ discovery potential after 10 years
Conclusions• Frejus (or TGV) tunnels offer an excellent quality underground site for megaton physics
• It is a the right distance from CERN to receive neutrino super and/or betabeams
• The Cerenkov technique is adequate given the low energy of the beams
• It offers the best sensitivity on 13 and δ compared to similar
projects (HyperK, BNL/FNAL)
• France (IN2P3/CEA) and Italy (INFN) have agreed to join efforts for the promotion of this project
• There is a successful coordination between nuclear physicists pushing EURISOL and neutrino physicists (common TDS)
•The first experiment able to detect CP violation could be installed in Europe before 2020, and it would also address the fundamental question of proton stability with some chance of discovery.
Short term:
• present the project to the SPSC at Villars
• prestudy results for the cavity
• write a white paper
• continue simulations and optimizations
THE END (but to be continued)
My warmest thanks to the all the people who have worked hard on this project
Special thanks to
Mats Lindroos
Mauro Mezzetto
Design Study
EURISOLBeta-beam Coordination
Beta-beam parameter group Above 100 MeV/u
Targets60 GHz ECR
Low energy beta-beamAnd many more…
USERSFrejus
Gran SassoHigh GammaAstro-Physics
Nuclear Physics(, intensity and
duty factor)
OTHER LABSTRIUMF
FFAGTracking
CollimatorsUS studyNeutrino
Factory DS
Conceptual Design # with price ### M€
scenario 1 (refurbished SPS) He6 350 Ne18 580scenario 2 (LHC) 1500 2500
scenario 1
scenario 2 400 kt detector at 730 km (off peak)
:to be studied :
• Is it possible to reach equilibrium at higher gamma ?
• Need sizeable increase in accelerating power
• Size of the decay ring
• cost
Which schedule?
• scenario 1: 2 year stop of SPS, after several years of LHC
• scenario 2: After LHC programm
I consider this project as a potential 2nd generation beta-beam,
not a competitor to the standard beta-beam