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NEMO-3 bb experiment First Results and Future Prospects. Ruben Saakyan, UCL UK HEP Neutrino Forum The Cosener’s House, Abingdon. Outline. Why NEMO-3 ? The Detector First results Sensitivity by 2007 Towards SuperNEMO. Currently Active Experiments. CUORICINO (bolometer). NEMO-3

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Nemo 3 bb experiment first results and future prospects

NEMO-3 bb experimentFirst Results and Future Prospects

Ruben Saakyan, UCL

UK HEP Neutrino Forum

The Cosener’s House, Abingdon


Outline
Outline

  • Why NEMO-3 ?

  • The Detector

  • First results

  • Sensitivity by 2007

  • Towards SuperNEMO


Nemo 3 bb experiment first results and future prospects

Currently Active Experiments

CUORICINO

(bolometer)

NEMO-3

(Tracking calorimeter)

<mn> = 0.4 eV ???

Heidelberg-Moscow exp is still running


Why nemo 3
Why NEMO-3 ?

  • One of the two experiments to improve <mn> sensitivity before 2007/2008 (0.15  0.5 eV) for a few isotopes

  • Well known (for us) technique orthogonal to other approaches

  • Excellent chance to understand nitty gritty of bb experiment…

  • ..and choose a project to attack n×10-2 eV scale


N eutrino e ttore m ajorana o bservatory
Neutrino Ettore Majorana Observatory

40 physicists and engineers

13 Laboratories/Universities

7 Countries


Uk nemo team so far
UK NEMO team (so far)

  • Phil Adamson, Leo Jenner, Ruben Saakyan, Jenny Thomas (all UCL)

  • Received approval from PPRP 27 Jan 03

  • Main involvement: data analysis..

  • ..but also some hardware tasks (PMT helium tests, light injection optimization)


Nemo 3 bb experiment first results and future prospects

  • From scintil detector:

  • st = 250 ps

  • From tracker:

  • s||= 1cm s = 0.45mm

  • (using timing information

  • on plasma propagation)

  • Calibration:

  • Laser survey

  • neutron Am/Be for

  • s||, s, e+ signature

  • e-207Bi, 90Sr for

  • energy calibration

  • 60Co for time alignment

Trigger:

1 scintillator hit > 150 keV

+

1 track: few Geiger planes

(flexible  3 – 7 Hz)


Nemo bb events
NEMO bb events

  • 3D pictures

  • study single electron spectra

  • study angular distributions

  • Detailed 2n information

  • O (105) 2n100Mo events/yr !

  • 7 isotopes


Nemo background events
NEMO background events

g  e+e-

e- (~7 MeV) from ng


Nemo 3 bb experiment first results and future prospects

  • Pure materials:

  • Source foils

  • measured with the

  • NEMO-3 detector

  • 208Tl < 2 mBq/kg

  • 214Bi < 2 mBq/kg

  • neutrons < 10-9 n cm-2s-1

  • Radon in the detector

  • 222Rn ~ 20 mBq/m3

  • 220Rn ~ 1.6 mBq/m3

  • to be improved with new

  • anti-radon system


Data taking
Data taking

  • June 2002: start with all 20 sectors, iron shielding, neutron shielding but…

  • …still a lot of debugging (both tracking detector and calorimeter)

  • 14 February 2003: start of routine data taking


Nemo 3 first results 100 mo 1200 h
NEMO-3 First Results100Mo 1200 h

2n:

T1/2=[7.4±0.05(stat)±0.8(sys)]×1018yr

(19000 events; S/B  50)

0n:

1 event in 2.8 – 3.2 MeV region

T1/2 > 1023 yr 90% CL

<mn> < 0.9 – 2.1 eV

World’s best result for 100Mo


Single state dominance ssd vs higher order state dominance hsd
Single State Dominance (SSD)VS Higher order State Dominance (HSD)

Simkovic, Domin, Semenov

nucl-th/0006084, Phys. Rev. C

HSD

1+

100Tc

SSD

0+

100Mo

0+

100Ru

  • Shape of single e- spectrum

  • Shape of 2b spectrum

  • Angular distribution

  • ~ 20% difference in T1/2

100Mo + NEMO-like detector can test it

experimentally !


Nemo 3 first results 100 mo 1200 h1
NEMO-3 First Results100Mo 1200 h

Angular distribution between two e-

single e- spectrum

Preliminary: SSD is preferred


Nemo 3 bb experiment first results and future prospects

NEMO-3 First Results

Other Isotopes

116Cd

82Se

150Nd

T1/2=[3.9±0.3(stat)±0.4(sys)]×1019

T1/2 > 1.0 × 1022 y 90% CL

T1/2=[8.2±0.4(stat)±0.8(sys)]×1019

T1/2 > 4 × 1022 y 90% CL

World’s best result !

T1/2=[7.0±0.7(stat)±0.7(sys)]×1018

T1/2 > 7.7 × 1020 y 90% CL


Nemo 3 0 nbb sensitivity 5 years
NEMO-3 0nbb sensitivity5 years

E = 2.8 – 3.2 MeV

100Mo

7 kg Qbb =3.034 MeV

External BG: 0

Internal BG:

radioactivity < 0.04 event/y/kg

2nbb = 0.11 event/y/kg

T1/2 > 3 × 1024 yr

<m> < 0.2 – 0.5 eV

82Se

1 kg Qbb =2.995 MeV

External BG: 0

Internal BG:

radioactivity < 0.01 event/y/kg

2nbb = 0.01 event/y/kg

T1/2 > 1 × 1024 yr

<m> < 0.6 – 1.2 eV

In case of full load of 82Se (~14kg) <m> < 0.15 – 0.3 eV


Supernemo not an official proposal yet
SuperNEMO (not an official proposal yet)

~ 100 kg 82Se (or other)

  • Sensitivity

    <mn> ~ 0.05 eV in 5 yr

  • Feasible if:

  • BG only from 2n (NEMO3)

  • b) DE/E = 10-11% at 1 MeV

  • (R&D needed)

4 supermodules,

planar geometry


Future bb projects comparison
Future bb projects comparison

* 5 different latest NME calculations


Concluding remarks
Concluding Remarks

  • 1200 h, T1/2(2n) for 4 isotopes; World’s best results for T1/2(0n) for 100Mo, 82Se

    By 2007/2008

  • NEMO-3 to reach <mn> < 0.15 - 0.5 eV (depending on 82Se availability)

  • Severalisotopes will be investigated

  • Unprecedented high 2n statistics with detailed information (single e- spectra, angular distributions) for 7 isotopes

    Experimental input to NME calculation


Concluding remarks ii
Concluding Remarks II

  • NEMO-3 will test experimentally feasibility of SuperNEMO

  • If yes  0.05 eV is achievable at relatively low cost and with very well known technology

  • If not  will not waste time and money and do something else



Nemo 3 bb experiment first results and future prospects

T0n1/2 = G0n |M0n|2 <mn>2

T2n1/2 = G2n |M2n|2