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