SuperNEMOThoughts about next generation NEMO experiment

Ruben Saakyan

UCL

Outline

Motivation Possible Scheme R&D needed Sensitivity Time scale

Motivation

Need to access <m> < 0.1 eV scale

Realistic project with sensitivity 0.05 eV with “modest” cost (~$15-20M)

NEMO technology very well known/understood

Measure background/source purity with NEMO

Feasibility estimate based on NEMO-3 results

The Idea

NEMO3×10 = SuperNEMO ~100 kg Candidate Isotopes: 100Mo, 82Se, 116Cd, 130Te Modular structure Improve energy resolution (see later) Time resolution 250ps, vertex: 1cm (1) – as in

NEMO3 Improve efficiency to from 12% to ~ 20%

No B-field ? (check with NEMO3) Better geometry Thinner wires in tracking detector Improved event selection

Which Isotope?

Isotope Q, MeV

100Mo 3.033

82Se 2.995

116Cd 2.802

130Te 2.529

2 821/ 22 100

1/ 2

( )~ 10

( )

T Se

T Mo

Factor of 10 lower BG for 82Se

Can be produced in centrifuge - $30K-$50K/kg

Possible Layouts

“Clone” structure 10×NEMO3

“Large scale” structure Source diameter – 25m

(passive shielding: 29m) “Intermediate”

4 cylinders with source diameter ~ 7m

NEMO-3 like

2.5 m

Possible Layouts

Low BG (NEMO) PMTs – 5000 (2.5×NEMO3)

30×30 ×10 cm3 scint blocks 30,000 Geiger cells

(5×NEMO3) Passive shielding: 20cm

Fe + 20-30cm antineutron shield

Space needed: 30 ×12 ×6m3

New Lab, Boulby? (visited on 17-July-03)

Planar Geometry (preferred)

4 supermodules25 kg each

Energy Resolution

2 – the only BG(check with NEMO3)

@ 3MeV:

E/E) = 3.5-4%(NEMO3)

(E/E) = 2.5-3%(SuperNEMO)

Gains factor of ~7

F ~ (E/E)6

Energy ResolutionScintillator R&D

Optimise: Optical coupling to

PMT Surface treatment Scint-r size PMT size

New scintillator? Combination of

organic/non-organic scintillator? MC input

UK contribution (MINOS scintillator experience)

207Bi

482 keV

976 keV

There are a few NEMO3 scint blocks withE/E 4.5% 2.5-3% @ 3 MeV

SuperNEMO advantages

Well known technology “Smart” detector (tracking) High Q-value Feasibility checked by NEMO-3

BG only from 2 (for 82Se and 100Mo) E/E 4.5% at 1 MeV (R&D)

Modular structure One supermodule even simpler than NEMO3

100kg of isotope “only” Modest price ~ $15M (isotope: $5-7M)

SuperNEMO disadvantages

Big detector Energy resolution (can be improved further?) Detection Efficiency

Sensitivity calculation

Assumptions:

• E/E = 4.5% @ 1MeV• = 20%• Isotope purity: 214Bi: < 50 Bq/kg 208Tl < 5 Bq/kg• Tmeasur = 5 yr

Sensitivity

Isotope

Q, MeV

Rad BG 2BG T1/2, yr <m>, eV

82Se

~3.0

0 1-2 2×1026 0.04-0.1

100Mo

~3.0

0 20 5×1025 0.04-0.1

116Cd

~2.8

10 5 4.5×1025 0.09-0.15

130Te

~2.5

100 0 2×1025 0.1-0.3

Time Scale

2-4 December 2003 – first meeting (LAL) to discuss R&D plans and proposal submission E/E (UK) Efficiency BG Isotope production/purification

2006: NEMO-3 upgrade with 10-12 kg of 82Se and run 2006-2010 ~0.1 eV

2008: Start SuperNEMO installation (new Frejus lab, Boulby?)

2010: Start taking data

Future projects sensitivity(5 yr exposure)

Experiment Source and

Mass

Sensitivity

to

T1/2 (y)

Sensitivity to

<m> (eV)*

Majorana

$50M

GENIUS

$100M

76Ge, 500kg

76Ge. 1000kg

3×1027

5×1027

0.03 – 0.07

0.02 – 0.05

CUORE

$25M

130Te, 750kg(nat)

2×1026 0.04 – 0.17

EXO

$50M-100M

136Xe

1 ton

8×1026 0.05 – 0.12

SuperNEMO

$15M

82Se(or other)

100 kg

2×1026 0.04 – 0.11

* 5 different latest NME calculations

Concluding Remarks

NEMO-3 will test experimentally feasibility of SuperNEMO First step: 10-12 kg 82Se from 2006

100kg 82Se ~0.04 eV is achievable at relatively low cost (~$15M) and with very well known technology

Could measure other isotopes Collaborators welcome

2-4 December 1st meeting at LAL(Orsay)