Double beta decays study with NEMO 3 and SuperNEMO CHAUVEAU - - PowerPoint PPT Presentation

c o l l a b o r a t i o n s u p e r n e m o

Double beta decays study with NEMO 3 and SuperNEMO

CHAUVEAU Emmanuel

• n behalf of the NEMO collaboration

University of Manchester

Rencontres de Moriond, Electroweak session

CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 1 / 20

Two-neutrinos and neutrinoless double beta decays

Atomic Number Z 32 34 36 38 40 Mass exces (MeV)

• 85
• 80
• 75
• 70
• 65
• 60

Ge

82

Se

82

Kr

82

Sr

82

Zr

82

As

82

Br

82

Rb

82

Y

82

β β 0.0 0.2 0.4 0.6 0.8 1.0

(E1 + E2) / Qββ

ββ2ν ββ0ν

Arbitrary unit

Two-neutrino double beta decay (ββ2ν) (A, Z) − → (A, Z + 2) + 2e− + 2¯ νe

second-order weak process

T ββ2ν

1/2

∼ 1020 years

allowed by Standard Model and observed input to nuclear physics model

Neutrinoless double beta decay (ββ0ν) (A, Z) − → (A, Z + 2) + 2e−

violates lepton number conservation requires a Majorana neutrino (ν = ¯

ν)

new physics : mββ, V+A, Majoron, SUSY... CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 2 / 20

Detection of neutrinoless double beta decay

Available observables

Electron energy sum E1 + E2

Discrimination ββ2ν vs. ββ0ν

Individual energy

E1, E2

Angular distribution

cos θ

• Study on possible ββ0ν mechanisms

MM V+A

0 0,2 0,4 0,6 0,8 1,0 1,5 1,0 0,5 |ΔE| / Qββ Γ⁻¹ d/ d(ΔE)

⁸²Se

Electron energy difference

• Eur. Phys. J. C. 70 p. 927(2010)

MM V+A

• 1 -0,6 -0,2 0,2 0,6 1

1,5 1,0 0,5 cos Θ Γ⁻¹ d/ d(cos Θ)

⁸²Se

Angular distribution

Mass Mechanism (MM)

u d d u d d u d u u d u e⁻ e⁻ W⁻ W⁻

( V - A )

⁻

eR eL

( V - A )

L L

Right Handed Current (V+A)

u d d u d d u d u u d u e⁻ e⁻ W⁻ W⁻

( V + A )

⁻

eR eR

( V - A )

L R

CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 3 / 20

Double beta decay experiments categories

e⁻

1

e⁻

2

source = calorimeter

pure calorimeter approach

V excellent detection efficiency V good energy resolution X no identification of electrons X high background

source calorimeter tracker

• r TPC

e⁻

1

e⁻

2

tracker + calorimeter approach

X low detection efficiency X poor energy resolution V electron recognition, ββ kinematic V background measurement + rejection

CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 4 / 20

The NEMO 3 detector (1)

Ultra low background detector

γ shielding : pure Iron (18 cm) n shielding : borated water (30 cm) + wood (40 cm) radon trapping facility from october 2004

→ radon-free air buffer around detector

location in Modane underground laboratory (LSM)

in Frejus tunnel : 4800 m.w.e. A(NEMO 3) ∼ 1000 Bq / 200 tons zoom in a NEMO 3 sector

CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 5 / 20

The NEMO 3 detector (2)

15 16 17 18 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 100Mo 130Te 116Cd

Cu

82S

e

natTe 130Te natTe 100Mo 100Mo 100Mo 100Mo 100Mo 100Mo 100Mo 100Mo 100Mo 100Mo 82S

e

48Ca 150Nd 96Zr

¹⁰⁰Mo 6,9 kg ⁸²Se 0,93 kg ¹³⁰Te 0,45 kg ⁴⁸Ca 6,99 g ⁹⁶Zr 9,43 g ¹⁵⁰Nd 36,5 g ¹¹⁶Cd 0,40 kg

NEMO-3 "camembert" (source top view) Unique features Multi-source detector : 7 ββ isotopes Particles identification : α, β−, β+, γ Kinematics of ββ decay : E1, E2, cos θ, ∆t ⇒ Topological signature of events ⇒ Background rejection + measurement ⇒ Study of ββ0ν, ββ2ν, ββ*, ...

internal Δt ~ 0 ns external Δt > 3 ns E1 t1 E2 t2 Double beta decay Measured + rejected background

"crossing" e⁻

β⁻ β⁻ e⁻ e⁺or e⁻ θ

• CHAUVEAU Emmanuel

Double beta decays study with NEMO 3 and SuperNEMO 6 / 20

Selection of candidate ββ events

Run : 3478 Event : 6930 Date : 09/11/2004 Event candidate for ββ2ν decay from ¹⁰⁰Mo foil E1 + E2 = 1.097 MeV internal hyp. : |Δtmeas - Δtcalc| = 0.33 ns external hyp. : |Δtmeas - Δtcalc| = 5.21 ns (Δvertex)t = 4.4 mm (Δvertex)z = 3 cm

Top view Side view

calorimeter hit track vertex

Two tracks Q < 0 Two calorimeter E > 200 keV Association track – calorimeter hit Common vertex Internal hypothesis (external event rejection) No other calorimeter hit (γ rejection) No delayed track (214Bi rejection) CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 7 / 20

Origin and mechanisms of NEMO 3 background

External γ

from detector radioactivity, neutrons and cosmics

Internal contamination in β emitter with Qβ ≥ Qββ (≈ 3 MeV)

214Bi in 238U chain

(Qβ = 3.3 MeV)

208Tl in 232Th chain (Qβ = 4.9 MeV)

Radon inside tracking detector

decay then deposit of daughter on wire and foil surfaces → feed contamination in 214Bi

ββ2ν background for ββ0ν signal

Foil

• e⁺

Pair creation e⁻ Foil

• e⁻

Compton + Møller e⁻ Foil

• e⁻

Double Compton e⁻

CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 8 / 20

Origin and mechanisms of NEMO 3 background

External γ

from detector radioactivity, neutrons and cosmics

Internal contamination in β emitter with Qβ ≥ Qββ (≈ 3 MeV)

214Bi in 238U chain

(Qβ = 3.3 MeV)

208Tl in 232Th chain (Qβ = 4.9 MeV)

Radon inside tracking detector

decay then deposit of daughter on wire and foil surfaces → feed contamination in 214Bi

ββ2ν background for ββ0ν signal

Foil β e⁻

• Beta

+ IC Foil β e⁻ Beta + Møller Foil β e⁻ Beta + Compton

• CHAUVEAU Emmanuel

Double beta decays study with NEMO 3 and SuperNEMO 8 / 20

Origin and mechanisms of NEMO 3 background

External γ

from detector radioactivity, neutrons and cosmics

Internal contamination in β emitter with Qβ ≥ Qββ (≈ 3 MeV)

214Bi in 238U chain

(Qβ = 3.3 MeV)

208Tl in 232Th chain (Qβ = 4.9 MeV)

Radon inside tracking detector

decay then deposit of daughter on wire and foil surfaces → feed contamination in 214Bi

ββ2ν background for ββ0ν signal

Foil β e⁻ Beta + Möller

²¹⁴Bi ²²²Rn

Q = 3.27 MeV

β 3.8 days

CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 8 / 20

Origin and mechanisms of NEMO 3 background

External γ

from detector radioactivity, neutrons and cosmics

Internal contamination in β emitter with Qβ ≥ Qββ (≈ 3 MeV)

214Bi in 238U chain

(Qβ = 3.3 MeV)

208Tl in 232Th chain (Qβ = 4.9 MeV)

Radon inside tracking detector

decay then deposit of daughter on wire and foil surfaces → feed contamination in 214Bi

ββ2ν background for ββ0ν signal 0.0 0.2 0.4 0.6 0.8 1.0 (E1 + E2) / Qββ

ββ2ν ββ0ν

Arbitrary unit CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 8 / 20

Measurement of NEMO 3 background

CHANNEL BACKGROUND MEASUREMENT eγexternal external background : 40K, 60Co, 226Ra, ... ecrossing e pure β emitters in foil : 234mPa, 40K, 90Y, ... eγ eγγ β+γ emitters in foil : 207Bi, 208Tl, 214Bi, ... eγγγ eα

222Rn in gas, 214Bi on foil and wires

Internal, external and radon background measurement Analysis through independent channels Model validation with a dedicated control foil (pure Cu) [ NIM A606 (2009) 449-465 ] ecrossing event

X 8 +

eγexternal event

CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 9 / 20

Measurement of NEMO 3 background : example with radon

channel eα : pure sample of "BiPo" events

²¹⁴Bi

19,7 m

²¹⁰Tl

1,3 m

²¹⁰Pb

21,4 a

²¹⁴Po

164 µs 0,02%

β α

²³⁸U

β α

²²²Rn

X 8 + O

eα event

10 3 10 4 10 5 200 400 600 800 1000 54.70 / 51 P1 0.1917E+05 16.05 P2 0.6688 0.1878E-01 P3 162.9 0.1633 P4 0.3174E+05 0.2284E+05 P5 16.31 2.481 Fraction of non α events: 0.59± 1.33%

α track delay (µs)

NIM A 606 (2009) 449-465

T1/2 = 162.9 μs

222Rn activity in NEMO 3 (mBq/m3) CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 10 / 20

NEMO 3 results : ββ2ν with 100Mo (phase 2 : 7 kg x 4 years)

Energy sum of 2 electrons Single electron energy Angular distribution

> 700000 events from 100Mo signal / background ratio = 76 T ββ2ν

1/2

= 7.16 ± 0.01 (stat) ± 0.54 (sys) x 1018 years [preliminary]

phase 1 : 7.11 ± 0.02 (stat) ± 0.54 (sys) x 1018 years [Phys. Rev. Lett. 95 182302 (2005)]

ultimate background component for ββ0ν signal CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 11 / 20

NEMO 3 results : ββ2ν summary

⁸²Se ¹¹⁶Cd ¹³⁰Te ¹⁵⁰Nd ⁹⁶Zr ⁴⁸Ca

9.6 ± 0.1 (stat) ± 1.0 (sys) x 10¹⁹ y [preliminary result] 2.88 ± 0.04 (stat) ± 0.16 (sys) x 10¹⁹ [preliminary result] 7.0 ± 0.9 (stat) ± 1.1 (sys) x 10²⁰ y [Phys. Rev. Lett. 107, 062504 (2011)] 9.11 ± 0.25 (stat) ± 0.63 (sys) x 10¹⁸ y [Phys. Rev. C 80, 032501 (2009)] 2.35 ± 0.14 (stat) ± 0.16 (sys) x 10¹⁹ y [Nucl. Phys. A 847 (2010)] 4.4 ± 0.5 (stat) ± 0.4 (sys) x 10¹⁹ y [preliminary result]

World best catalogue of ββ2ν half-lifes first direct detection for 130Te

CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 12 / 20

NEMO 3 results : search for ββ0ν

¹⁰⁰Mo : 7.0 kg x 4.5 years

Events in [2.8 - 3.2] MeV : DATA = 18 T

• tal MC = 16.4 ± 1.4

T ββ0ν

1/2

> 1.0 x 1024 years

(90 % CL)

mββ < 310 – 960 meV

⁸²Se : 0.9 kg x 4.5 years

Events in [2.8 - 3.2] MeV : DATA = 14 T

• tal MC = 10.9 ± 1.3

T ββ0ν

1/2

> 3.2 x 1023 years

(90 % CL)

mββ < 940 – 2600 meV

NME

QRPA Kortelainen and Suhonen, Phys. Rev. C75 051303 (2007) QRPA Kortelainen and Suhonen, Phys. Rev. C76 024315 (2007) QRPA Simkovic et al., Phys. Rev. C77 045503 (2008) IBM2 Barea and Iachello, Phys. Rev. C79 044301 (2009) PHFB Rath et al., Phys. Rev. C82 064310 (2010) SM Caurrier at al., Phys. Rev. Lett. 100 052503 (2008)

CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 13 / 20

NEMO 3 results : other ββ results

ββ* of 100Mo [Nucl. Phys. A781 (2006) 209] ββ2ν 0+ → 0+

1

T1/2 = 5.7+1.3

−0.9 (stat) ± 0.8 (syst) x 1020 y

ββ0ν 0+ → 0+

1

T1/2 > 8.9 x 1022 y (90 % C.L.) ββ2ν 0+ → 2+

1

T1/2 > 1.1 x 1021 y (90 % C.L.) ββ0ν 0+ → 2+

1

T1/2 > 1.6 x 1023 y (90 % C.L.) ββ0νB (Majoron) [Nucl. Phys. A765 (2006) 483] mode

100Mo 82Se

n = 1 T1/2 > 2.7 x 1022 y T1/2 > 1.5 x 1022 y n = 2 T1/2 > 1.7 x 1022 y T1/2 > 6.0 x 1021 y n = 3 T1/2 > 1.0 x 1022 y T1/2 > 3.1 x 1021 y n = 7 T1/2 > 7.0 x 1019 y T1/2 > 5.0 x 1020 y ββ0ν V+A

100Mo :

T1/2 > 5.7 x 1923 years λ < 1.4 x 10−6

82Se :

T1/2 > 2.4 x 1923 years λ < 2.0 x 10−6

100Mo

0+ 21

+ (540 keV)

01

+ (1130 keV)

41

+ (1227 keV)

0+ (g.s.)

100Ru

22

+ (1362 keV)

3034 keV

1 2

CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 14 / 20

NEMO 3

– january 2011 – – october 2011 – NEMO 3 experiment

8 years of successfull data taking fully disassembled during 2011 final analysis in progress CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 15 / 20

SuperNEMO detector

Target sensitivity : T ββ0ν

1/2

> 1 x 1026 years ⇐ ⇒ mββ < 50 – 100 meV

NEMO 3 SuperNEMO Isotope

100Mo 82Se (or 150Nd, or 48Ca)

Exposure 7 kg x 5 years 100 kg x 5 years Efficiency 18 % 30 % Energy resolution (FWHM) 8 % @ 3 MeV 4 % @ 3 MeV A(208Tl) foil ∼ 100 µBq/kg ≤ 2 µBq/kg A(214Bi) foil < 300 µBq/kg ≤ 10 µBq/kg A(222Rn) gas 5 mBq/m3 ≤ 0,15 mBq/m3 A SuperNEMO module (x 20)

5 kg of ββ source drift chamber of 2000 Geiger cells 550 PVT scintillators + 8" PMTs CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 16 / 20

SuperNEMO : Research & Developmentm status

BiPo3 detector

Source : 5 kg already ready 214Bi and 208Tl radiopurity control by a dedicated detector (BiPo3) Tracker : required performances demonstrated with a 90-cells protoype

automated wiring robot under construction (mass production + ultra clean condition)

Calorimeter : 7.2 % FWHM @ 1 MeV reached

(NEMO 3 : 14 % @ 1 MeV)

Radon : emanation and permeability measurement being lead

radon concentration line for high sensitivity measurement (100 µBq/m3)

CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 17 / 20

SuperNEMO : Research & Developmentm status

Source : 5 kg already ready 214Bi and 208Tl radiopurity control by a dedicated detector (BiPo3) Tracker : required performances demonstrated with a 90-cells protoype

automated wiring robot under construction (mass production + ultra clean condition)

Calorimeter : 7.2 % FWHM @ 1 MeV reached

(NEMO 3 : 14 % @ 1 MeV)

Radon : emanation and permeability measurement being lead

radon concentration line for high sensitivity measurement (100 µBq/m3)

CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 17 / 20

SuperNEMO : Research & Developmentm status

Energy (MeV) 0.4 0.6 0.8 1 1.2 1.4 1.6 FWHM - Energy (%) 5 6 7 8 9 10 11 12

Entries 34370 Mean 0.9718 RMS 0.1105 / ndf

2

χ 204.7 / 212 Constant 1.7 ± 218.8 Mean 0.0003 ± 0.9979 Sigma 0.00024 ± 0.03407

Energy (MeV) 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 50 100 150 200 250

Entries 34370 Mean 0.9718 RMS 0.1105 / ndf

2

χ 204.7 / 212 Constant 1.7 ± 218.8 Mean 0.0003 ± 0.9979 Sigma 0.00024 ± 0.03057

1 MeV e⁻ spectrum ΔE E = 7.2 % E (FWHM)

Source : 5 kg already ready 214Bi and 208Tl radiopurity control by a dedicated detector (BiPo3) Tracker : required performances demonstrated with a 90-cells protoype

automated wiring robot under construction (mass production + ultra clean condition)

Calorimeter : 7.2 % FWHM @ 1 MeV reached

(NEMO 3 : 14 % @ 1 MeV)

Radon : emanation and permeability measurement being lead

radon concentration line for high sensitivity measurement (100 µBq/m3)

CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 17 / 20

SuperNEMO : Research & Developmentm status

radon concentration line

Source : 5 kg already ready 214Bi and 208Tl radiopurity control by a dedicated detector (BiPo3) Tracker : required performances demonstrated with a 90-cells protoype

automated wiring robot under construction (mass production + ultra clean condition)

Calorimeter : 7.2 % FWHM @ 1 MeV reached

(NEMO 3 : 14 % @ 1 MeV)

Radon : emanation and permeability measurement being lead

radon concentration line for high sensitivity measurement (100 µBq/m3)

CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 17 / 20

SuperNEMO demonstrator (first module)

a ZERO background experiment (< 0.06 events/years) physics with 2.5 years x 7 kg of 82Se

– T ββ0ν

1/2

sensitivity of 2.6 x 1024 years – test Klapdor-Kleingrothaus claim

construction has started (tracker) installation for 2014 in LSM at NEMO 3 place

Demonstrator integration at LSM

CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 18 / 20

Conclusions

NEMO 3

8 years of successful data taking a reference for ββ decays study :

ββ2ν, ββ0ν, ββ*, ββ0νB, ...

analysis of full dataset on progress

→ final results by end 2012 SuperNEMO

successful R&D unique detector approach :

event topology, isotope flexibility, modularity, ...

first module will start taking data in 2014 sensitivity of 50 – 100 meV on mββ by 2020 possibility to probe ββ0ν mechanism CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 19 / 20

Thank you for your attention !

NEMO 3/SuperNEMO collaboration meeting at Caen, October 2011

CHAUVEAU Emmanuel Double beta decays study with NEMO 3 and SuperNEMO 20 / 20