Neutrinoless double beta decay search using Xe: The …...Neutrinoless double beta decay search...

Neutrinoless double beta decay search using 136Xe: The NEXT

experiment.

LAL Seminar, December 2011.

Héctor Gómez Maluenda

[email protected]

LAL Seminar. December 2011 2

OUTLINE

Neutrino and double beta decay.

The Experiment.Why HP Xe TPC?

The SOFT concept.

Present Status.Prototypes.

NEXT-μM.

NEXT-100.

Outlook.

Summary.


NEUTRINO AND DOUBLE BETA DECAY

Neutrino oscillation experiments have shown that neutrino is a non-zero mass particle, implying the existence of Physics beyond the Standard Model of Particles.




It is also known that neutrino mass could have two different mass hierarchies: normal and inverse.

Normal hierarchy: m1

∼m2

>m3 (Δm23)2




It is also known that neutrino mass could have two different mass hierarchies: normal and inverse.

Unfortunately, neutrino oscillation experiments can only measure (Δmij )2.

HOW TO MEASURE THE ABSOLUTE MASS VALUE OF THE NEUTRINO?

End point study of the 3H decay energy spectrum

(KATRIN)

Upper limits from Astrophysical Observations

(SN 1987-A)

NEUTRINOLESS DOUBLE BETA DECAY DETECCTION

(0νββ)



Double beta decay processes:

d

d

u

u

W

W

e

eν

ν

x

d

d

u

u

W

W

e

eν

d

d

u

u

W

W

e

eν

ν

d

d

u

u

W

W

e

eν

ν

x

d

d

u

u

W

W

e

eν x

d

d

u

u

W

W

e

eν

( )( )2220

02222

=++→

=+++→−−−

−−−

ΔL; e)(A,Z:(A,Z)βνβ

ΔL; νe)(A,Z:(A,Z)βνβ e

( ) 21021

2

220

2

20

010

21 00

/ν/Neν

e

ννF

A

VνGTν

ν/

TFmm

mm

MggMG)(T

−

−++

=

−=→

0νββ process detection:

∑=j

jejmUm2

ν

ν Majoranaνν ⇒=

2νββ0νββ



Study of the 0νββ decay for almost 20 years. Some experiments already finished:

Experiment Isotope Technique LaboratoryResults

T1/20ν (y) (eV)

IGEX 76Ge Ge Diodes Canfranc ≥

1.57 1025 ≤

0.33-1.35

HEIDELBERG- MOSCOW

76Ge Ge Diodes Gran Sasso ≥

1.55 1025 ≤

0.35

HEIDELBERG- MOSCOW*

76Ge Ge Diodes Gran Sasso 1.20 1025 0.44

MIBETA128Te

Bolometers Gran Sasso≥

8.60 1022≤

1-2130Te ≥

1.44 1023

CUORICINO 130Te Bolometers Gran Sasso ≥

3.00 1024 ≤

0.19-0.68

NEMO 3100Mo Track

+ Calorimetry Modane

≥

1.00 1024 ≤

0.31-0.96

82Se ≥

3.2 1023 ≤

0.94-2.60

*H.V. Klapdor-Kleingrothaus

et al. Phys. Lett. B 578:54 & 586:198 (2004)



Where are we going now? New generation experiments.

Trying to reach sensitivities to explore ~ 50 meV.

Some requirements are mandatory:Big amount of ββ emitter mass.

Radiopure materials.

Placement underground.

Background events discrimination.

…

Klapdor’s claim could be checked.

50 meV

KK claim



If no signal is found:

bΓMTε

Wf.Fat

D2610174 ×=

• Isotopic abundance ↑↑

• Atomic weight ↓↓

• Detection efficiency ↑↑

• Exposure ↑↑

• Background level ↓↓

• Energy resolution ↓↓

Several techniques, isotopes and detectors proposed trying to optimize FD

.

( ) 21021 /ν/Neν TFmm −= ( )21/

DNeν FFmm−



Experiment Isotope Technique Main StrengthCANDLES 48Ca CaF2

Scintillation Background, Efficiency

CARVEL 48Ca CaWO4

Scintillation Mass, Efficiency

COBRA 130Te, 116Cd ZnCdTe

Semiconductors Resolution, Efficiency

CUORE 130Te Bolometers Resolution, EfficiencyCUORICINO 130Te Bolometers Resolution, Efficiency

DCBA 150Nd Gaseous TPC Bkg Rejection, EfficiencyEXO 136Xe TPC Ionization + Scintillation Mass, Efficiency, Final State Signal

GERDA 76Ge Ge

Diodes Resolution, Efficiency

MAJORANA 76Ge Ge


MOON 100Mo Tracking + Calorimetry Compactness, Bkg RejectionNEXT 136Xe Tracking + Calorimetry Bkg Rejection, Efficiency

SNO++ 150Nd Nd

Liquid Scintillation Mass, Efficiency

SUPERNEMO 82Se, 150Nd Tracking + Calorimetry Bkg Rejection, Isotope SelectionXMASS 136Xe Liquid Xe Mass, Efficiency

YANGYANG 124Sn Sn


Some new generation 0νββ experiments:



Experiment Isotope Technique Main StrengthCANDLES 48Ca CaF2

Scintillation Background, Efficiency

CARVEL 48Ca CaWO4

Scintillation Mass, Efficiency

COBRA 130Te, 116Cd ZnCdTe

Semiconductors Resolution, Efficiency

CUORE 130Te Bolometers Resolution, EfficiencyCUORICINO 130Te Bolometers Resolution, Efficiency

DCBA 150Nd Gaseous TPC Bkg Rejection, EfficiencyEXO 136Xe TPC Ionization + Scintillation Mass, Efficiency, Final State Signal

GERDA 76Ge Ge


MAJORANA 76Ge Ge


MOON 100Mo Tracking + Calorimetry Compactness, Bkg RejectionNEXT 136Xe Tracking + Calorimetry Bkg Rejection, Efficiency

SNO++ 150Nd Nd


SUPERNEMO 82Se, 150Nd Tracking + Calorimetry Bkg Rejection, Isotope SelectionXMASS 136Xe Liquid Xe Mass, Efficiency

YANGYANG 124Sn Sn


Some new generation 0νββ experiments:


THE EXPERIMENT

The NEXT (Neutrino Experiment with a Xenon TPC) experiment expects tomeasure the 0νββ decay of 136Xe using a high pressure Xenon TPC.

U. Coimbra

U. Aveiro CEA-Saclay

JINR

IFIC, U. A. Madrid, U. GironaU. Politécnica

Valencia,

U. Santiago, U. Zaragoza.

LBNL, Texas A&M, J. Hopkins

U. Antonio Nariño, Bogotá


bΓMTε

Wf.Fat

D2610174 ×=( ) 21/DNeν FFmm −<

THE EXPERIMENT


WHY A HP XENON TPC?Let’s try to find the answer in these equations:


bΓMTε

Wf.Fat

D2610174 ×=( ) 21/DNeν FFmm −<

THE EXPERIMENT

Xe is not difficult to enrich.Ability of purification and reuse of the enriched Xe.


bΓMTε

Wf.Fat

D2610174 ×=

THE EXPERIMENT

Xe is not difficult to enrich.Ability of purification and reuse of the enriched Xe.136Xe has higher Wat compared with other isotopes considered.

( ) 21/DNeν FFmm −


bΓMTε

Wf.Fat

D2610174 ×=

THE EXPERIMENT

Xe is not difficult to enrich.Ability of purification and reuse of the enriched Xe.136Xe has higher Wat compared with other isotopes considered.Source = detector experiment.



bΓMTε

Wf.Fat

D2610174 ×=

THE EXPERIMENT

Xe is not difficult to enrich.Ability of purification and reuse of the enriched Xe.136Xe has higher Wat compared with other isotopes considered.Source = detector experiment.High pressure Bigger amount of emitter.Scalable to higher masses.



bΓMTε

Wf.Fat

D2610174 ×=

THE EXPERIMENT

Xe is not difficult to enrich.Ability of purification and reuse of the enriched Xe.136Xe has higher Wat compared with other isotopes considered.Source = detector experiment.High pressure Bigger amount of emitter.Scalable to higher masses. High Qββ value (2457.83 keV).

Qββ

(136Xe) = 2457.83 keVM. Redshaw

et al, PRL 98 (2007) 053003



bΓMTε

Wf.Fat

D2610174 ×=

THE EXPERIMENT

Xe is not difficult to enrich.Ability of purification and reuse of the enriched Xe.136Xe has higher Wat compared with other isotopes considered.Source = detector experiment.High pressure Bigger amount of emitter.Scalable to higher masses. High Qββ value (2457.83 keV).Long T1/22νββ (2.11 ± 0.048(stat.) ± 0.21(sys.) x 1021 y).

( ) 21/DNeν FFmm −<

arXiv: 1108.4193v2 [nucl-ex]


bΓMTε

Wf.Fat

D2610174 ×=

THE EXPERIMENT

Xe is not difficult to enrich.Ability of purification and reuse of the enriched Xe.136Xe has higher Wat compared with other isotopes considered.Source = detector experiment.High pressure Bigger amount of emitter.Scalable to higher masses. High Qββ value (2457.83 keV).Long T1/22νββ (2.11 ± 0.048(stat.) ± 0.21(sys.) x 1021 y).Possibility to detect Ionization/Scintillation and to study Tracking.



bΓMTε

Wf.Fat

D2610174 ×=

THE EXPERIMENT

Xe is not difficult to enrich.Ability of purification and reuse of the enriched Xe.136Xe has higher Wat compared with other isotopes considered.Source = detector experiment.High pressure Bigger amount of emitter.Scalable to higher masses. High Qββ value (2457.83 keV).Long T1/22νββ (2.11 ± 0.048(stat.) ± 0.21(sys.) x 1021 y).Possibility to detect Ionization/Scintillation and to study Tracking.Good energy resolution.



( ) 21/DNeν FFmm −<

THE EXPERIMENT

Xe is not difficult to enrich.Ability of purification and reuse of the enriched Xe.136Xe has higher Wat compared with other isotopes considered.Source = detector experiment.High pressure Bigger amount of emitter.Scalable to higher masses. High Qββ value (2457.83 keV).Long T1/22νββ (2.11 ± 0.048(stat.) ± 0.21(sys.) x 1021 y).Possibility to detect Ionization/Scintillation and to study Tracking.Good energy resolution.FN is worse if compared with other isotopes.

bΓMTε

Wf.Fat

D2610174 ×=


THE EXPERIMENT

Xe is not difficult to enrich.Ability of purification and reuse of the enriched Xe.136Xe has higher Wat compared with other isotopes considered.Source = detector experiment.High pressure Bigger amount of emitter.Scalable to higher masses. High Qββ value (2457.83 keV).Long T1/22νββ (2.11 ± 0.048(stat.) ± 0.21(sys.) x 1021 y).Possibility to detect Ionization/Scintillation and to study Tracking.Good energy resolution.FN is worse if compared with other isotopes.

Difficulty to design a compact experiment.Typical problems coming from working at High Pressure (~10 bars).

( ) 21/DNeν FFmm −< bΓMTε

Wf.Fat

D2610174 ×=


THE EXPERIMENT


Events detection is based on the SOFT TPC concept.Separated-Optimized Energy Function from Tracking


THE EXPERIMENT

SOFT TPC: Separate-Optimized Energy Function from Tracking.

The experiment will have a better sensitivity if we are capable to obtain as accurate as possible:

Energy of the event (with good resolution).

Time of the event (t0, related to z position).

Track of all the particles of the event.

These characteristics will allow not only to determine the energy of the event, but also to reconstruct it in order to apply pattern recognition to discriminatebackground events from 0νββ ones.


THE EXPERIMENT


Electroluminescence region (higher E)SiPM

plane

Field Cage

PMT plane

E


THE EXPERIMENT


SiPM

plane:Electroluminescence Light Tracking

Field Cage

PMT plane:Primary scintillation t0Electroluminescence Light Energy

E


PRESENT STATUS: PROTOTYPES

Different small and medium size TPCs to test and improve elements that will be used in the final setup.

Detectors: Energy Resolution, Time Stability…

Vessel and internal components: Outgassing, Leak rates…

DAQ

There are still decisions to be taken about some features of NEXT-100.

NEXT DBDM NEXT DEMO NEXT μM



NEXT DBDM:

Test PMTs energy resolution in HP Xe (up to 15 bar).



NEXT DBDM:

Test PMTs energy resolution in HP Xe (up to 15 bar).

Promising results.

1% FWHM @ 662 keVDrift Field: 0.05 kV/cm/bar

EL Field: 2 kV/cm/bar

Primary Scint. also observed

Work with higher Drift Fields.

Radial dependence and other points to clarify.



NEXT DEMO:

Analog to the NEXT-100 baseline detector concept.

Ø = 16 cm Vs ~ 1 lØ = 16 cm SV ~ 6 l

mXe

~ 0.34 kg @ 10 bar



NEXT DEMO:


PMT Plane (t0

and Energy) SiPM

Plane (Tracking)



NEXT DEMO:


Prototype just commissioned (only preliminary calibrations done).

S1 S2



NEXT μM:

Testing of different Xe-base mixtures (effects on the energy resolution).

Outgassing and Leak Rates for Feedthorughs and internal components.

But Also…



NEXT μM:



But Also…

Study of Micromegas detector as alternative to the baseline.

No operational problems in HP

Long term stability

Radiopure solution

Capable to register energy and tracking

Ongoing studies to see EL

…



NEXT μM:



But Also…



Long term stability

Radiopure solution



…

S. Cebrián et al, Astrop

Phys 34 (2011) 354-359



NEXT μM:



But Also…



Long term stability

Radiopure solution



…



NEXT μM:

~ 79 l Stainless Steel Chamber.

Ø = 28 cm and 35 cm Drift Length for 21.5 l of sensitive volume.

Up to ~1.2 kg of Xe @ 10 bar in the sensitive volume.



NEXT μM:




In a first step the prototype was fully equipped with:

Bulk mM detector Ø ~ 30 cm.

Copper + Peek + Cirlex Field Cage.

Teflon + Copper HV Feedthrough.

Readout Feedthrough.



NEXT μM:











NEXT μM:









Before to measure:

Pressure Tests

Vacuum and Outgassing measurements

HV and many others…


0 50 100 150 200 250 30010,75

10,80

10,85

10,90

10,95

11,00

11,05

NEXT I pressure (bar) Temperature (؛C)

Time (hours)

Pre

ssur

e (b

ar)

20

21

22

23

24

25

26

27

28

Temperature (؛C

)


NEXT μM: Pressure Tests.

Useful to test the vessel but also the Gas System to put the gas inside the vessel (valves, flowmeters, …)

11 bar of Ar

Monitoring of P and T



NEXT μM: Pressure Tests.

Useful to test the vessel but also the Gas System to put the gas inside the vessel (valves, flowmeters, …)

0 50 100 150 200 250 3000.03660

0.03665

0.03670

0.03675

0.03680

P/T

(bar

/K)

Time (hours)

11 bar of Ar

Monitoring of P and T

11 bars

constant during

more than 10 days



NEXT μM: Vacuum and outgassing measurements.

To keep the purity of gas, elements in contact must not emanate any contaminant.

In principle the inner materials were chosen with this purpose.

Bake-out cycles To “clean” possible impurities.

0

0

ttVolume)P(P(t)

sl mbar Outgassing

−×−

=⎟⎠⎞

⎜⎝⎛ ×

0 20 40 60 80 100 120 140 160 18010-7

10-6

10-5

10-4

10-3

10-2

10-1

100

101

102

103

Time (hours)

Pre

ssur

e (m

bar)

Pressure (mbar) Control Temperature (؛C) "Environmental" Temperature (؛C)

0

20

40

60

80

100

120

140

160

180

200

Temperature (؛C

)

0 50 100 150 200 250 300 350 4000,0

2,0x10-5

4,0x10-5

6,0x10-5

8,0x10-5

1,0x10-4

Pres

sure

(mba

r)

Time (s)

P < 10-6

mbar Og

< 10-6

mbar l/s



NEXT μM: Other tests.

HV tests to check that Electric Field needed for the Drift is reachable.

Installation of the electronics close to the vessel.

DAQ based on AFTER chip.

Possibility to read mesh (E) and pixels (track) of the μM simultaneously.



NEXT μM: First measurements.222Rn source diffused in the gas (Ar-iC4H10 5%)

~ 6 MeV α inside the sensitive volume.

0 1000 2000 30000

20

40

60

80

100

120

140

160

180

200

Cou

nts/

Cha

nnel

(1.5

hou

rs)

Ch

Vpixel = 250 VVdrift = 3000 V

Mesh

Spe

ctrum





-5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 7510

11

12

13

14

15

16

17

18

Rat

e (H

z)

Time (hours)

R=R0 e-λt

R0 = 17.5 +- 0.05

λ = 140.55 +- 1.66 h-1

T1/2 = 4.05 +- 0.05 days





3-D Energy Distribution 2-D Event Reconstruction



NEXT μM: Presents Status.

Prototype fully operative with Bulk μM.

Possible to register Energy and 2-D tracks.

Next steps:

Installation of microbulk mM LARGEST SURFACE COVERED

Complete the system to register t0 3-D tracks


PRESENT STATUS: NEXT 100

NEXT 100 will be placed at Canfranc Underground Laboratory (LSC), in the Spanish Pyrenees (2450 m.w.e.).



NEXT 100 time schedule:

Commissioning of the detector along 2013.

Start data taking in 2014.

Technical Detector Report (TDR) finished:

Pressure Vessel (SS + internal Cu shielding)








Field Cage








Field Cage

PMTs and MPPCs








Field Cage

PMTs and MPPCs

Shielding








Field Cage

PMTs and MPPCs

Shielding

Radiopurity measurements Bkg Model

Simulations

…

EXPECTED TO REACH THE ~ 50 meV SENSITIVITY


OUTLOOK

PROTOTYPES:

Data taking and test of different element and techniques that will be used in NEXT 100.

NEXT 100:

Construction and Commissioning of Shielding and Gas System (2012).

Final Design and Manufacture of Pressure Vessel (2011-2012).

Construction and Characterization of Detector Planes (2012).

Construction of Field Cage and HV Feedthroughs (2012).

Commissioning of NEXT 100 at LSC (from ~ June 2013).

Start Data Taking (2014).


SUMMARY

0νββ is a hot topic in Particle Physics.

New generation experiments aim to explore new regions for the neutrino effective mass around 50 meV.

NEXT experiment expects to reach this sensitivity using a HP Xe TPC.

NEXT prototypes are showing that the technology chosen could be suitable for this objective.

NEXT 100 design is already finished and works to construct the setup will start in 2012.

The goal is to start the data taking in 2014.

IS A REALLY AMBICIOUS TIME LINE… BUT LET’S TRY IT

Neutrinoless double beta decay search using 136Xe: The NEXT

experiment.

LAL Seminar, December 2011.

Héctor Gómez Maluenda

[email protected]

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Neutrinoless double beta decay search using Xe: The …...Neutrinoless double beta decay search...

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