Seminář ÚČJF - Vít Vorobel 1

Hmotná neutrinaVít Vorobel, ÚČJF MFF UK

• Úvod (milníky, pojmy)– Kinematická měření mn

– Oscilace neutrin (mixování neutrin)– Dvojný beta-rozpad (Majorana x Dirac ?)

• Experiment NEMO-3 – dvojný beta-rozpad• Experiment SuperNEMO• Experiment Daya Bay – oscilace reaktorových antineutrin

24.03.2010

Seminář ÚČJF - Vít Vorobel 2

Neutrinové milníky• 1930 Pauli – neutrální částice v b-rozpadu• 1937 Majorana – co když n = anti-n ?• 1956 Reines, Cowan – pozorování reaktorových anti-n• 1957 Pontecorvo – hypotéza oscilací neutrin• 1968 Davis – pozorování slunečních n (deficit)

• množství experimentů a trpělivost

• 1998 Super-Kamiokande – pozorování oscilací atmosférických n

• .................................................................................

• 80 let poté• 2010 Hierarchie? Majorana? Hmotnost? Proč tak

malá? ...24.03.2010

Seminář ÚČJF - Vít Vorobel 3

i

iiii UU

*

100

00

00

100

0cossin

0sincos

cos0sin

010

sin0cos

cossin0

sincos0

0012/

2/

1212

1212

1313

1313

2323

23232

1

i

i

i

i

e

e

e

e

U

Základní formalizmus - mísení neutrin

• Slabé stavy• Hmotnostní stavy• Směšovací matice Pontecorvo-Maki-Nakagawa-Sakata

• Informace o hmotnosti neutrin (9 parametrů)– Hmotnosti (3)– Parametry PMNS matice

• Směšovací úhly (3)• Diracova fáze (1)• Majoranovy fáze (2)

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3,2,1,

,,

im

e

ii

21

132312

321

mmm

22222 2 mpmmmm

35 0

Kinematická měření .• Beta – rozpad 3H

– Mainz, Troick, mne < 2 eV/c2

– KATRINE, plánovaná citlivost 0.2 eV/c2

• Rozpad p – PSI, mnm < 170 keV/c2

• Rozpad t – OPAL, DELPHI,ALEPH• mnt < 18 MeV/c2

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22,e

mEQEQpEZEFEN

222i

ii mUm

Seminář ÚČJF - Vít Vorobel 5

E

cmEcmEpcctxcmE i

ii 2

424222

ii

iii

i

ii Ux

E

cmiUx

E

cmiUx

2exp

2exp

32*

32*

xE

cmUUUUx

E

cmUUUUxP ij

jijjii

ij

jijjii 2

sinIm24

sinRe432

**32

2**2

02

exp0exp0exp32

2i

iiiiiiii x

E

cmipxtE

icm

i

222jiij mmm

2232

22 48.24

sin2sineVm

MeVEm

cm

EL

L

xP

Oscilace neutrin .• Oscilace ve vakuu - Pontecorvo 1957

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• Oscilace v hmotném prostředí - Wolfenstein 1978, Mikheyev-Smirnov 1985 (MSW effect)– významný efekt pro sluneční a urychlovačová neutrina– Z0 : ne, nm, n t

– W+: pouze ne

– Efektivní mi jsou jiná v prostředí než ve vakuu

ijjiij mmm 2sin 2222

2 neutrina: oscilační délka

Seminář ÚČJF - Vít Vorobel 6

bb-rozpad

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i

ieie mUm 2

(A,Z)(A,Z+2) + 2e- + 2n (A,Z)(A,Z+2) + 2e-

2: proces dovolený v SM, T1/2 ~ 1020y 0: proces mimo SM, T1/2 1025y

22

0002/1

),(1

evvmMZQG

T

Seminář ÚČJF - Vít Vorobel 7

NEMO-3/SuperNEMO collaboration

Neutrino Ettore Majorana Observatory(Neutrino Experiment on MOlybdenum – historical name)

80 physicists / 30 institutions

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Seminář ÚČJF - Vít Vorobel 8

0nbb and neutrino fundamental properties

Probe of neutrino nature. Neutrinos are Majorana fermions (particle antiparticle) if 0 takes place See-Saw mechanism, Leptogenesis, Baryon asymmetry, CP violation

Neutrino mass hierarchy. 0 measurements might help to establish the right one.

Absolute mass scale. 0 experiments are among the most sensitive ones.

Spreads are due to variations of unknown CP phases

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Seminář ÚČJF - Vít Vorobel 9

3 m

4 m

B (25 G)

Source: 10 kg of isotopes cylindrical, S = 20 m2, 60 mg/cm2

Tracking detector: drift wire chamber operating in Geiger mode (6180 cells)Gas: He + 4% ethyl alcohol + 1% Ar + 0.1% H2O

Calorimeter: 1940 plastic scintillators coupled to low radioactivity PMTs

The NEMO3 detector

Fréjus Underground Laboratory : 4800 m.w.e.

Magnetic field: 25 GaussGamma shield: Pure Iron (18 cm)Neutron shield: borated water (~30 cm) + Wood (Top/Bottom/Gaps between water tanks)

Able to identify e-, e+, g and -a delayed

20 sectors

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Seminář ÚČJF - Vít Vorobel 10

NEMO3 unique features

Multi-source detector Measurement of full bb-event pattern

Self-determination of ALL background components measuring independent channels

Multisource bb-detector

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Seminář ÚČJF - Vít Vorobel 11

Unique spectra from tracko-calo technique

100Mo 2 ResultsNEMO-3 ’’2n-factory’’ in action

Sum energy spectrum Angular distributionSingle electron energy spectrum

• Data- MC ββ2- background subtracted

100Mo

Latest results:

219 000 events389 daysS/B=40

100Mo 100Mo

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12

100Mo 2 ResultsSummary of NEMO-3 2n-results

IsotopeExpo-sure, days

Events S/B T1/2(2νββ), years

Published

100Mo 389 219000 40 (7.11 ± 0.02(stat)±0.54(syst))·1018 (SSD favored)

100Mo(0+1) 334.3 37,5 4 (5.7+1.3

-0.9(stat) )±0.8(syst))·1020

82Se 389 2750 4 (9.6± 0.3(stat)±1.0(syst))·1019

116Cd 168.4 1371 7.5 (2.8± 0.1(stat)±0.3(syst))·1019

150Nd 939 2018 2.8 (9.11+0.25-0.22(stat)±0.63(syst))·1018

New preliminary

130Te 1152 236 0.35 (6.9± 0.9(stat)±1.0(syst))·1020

96Zr 1221 428 1 (2.35± 0.14(stat)±0.16(syst))·1019

48Ca 943.2 116 6.8 (4.4+0.5-0.4(stat)±0.4(syst))·1019

Systematic studies of 2nbb process provide crucial knowledge for 0nbb search!

100Mo 2 Results0n-results

IsotopeT1/2(0νββ) limit,

×1024years <mn>, eV Experiment Year

76Ge > 15.7 <0.3-1.35 IGEX 2002

76Ge 15. 0.17-0.45 HM(KGC) 2004

76Ge > 15.5 <0.3-1.35 HM(Others) 2005

130Te >3 <0.2-0.7 CUORICINO 2008

100Mo >1.1 <0.45-0.93 NEMO-3 2009

From NEMO to SuperNEMO

SUPERNEMO R&D is in progress since 2006

NEMO-3 SuperNEMO

100Mo, 7kg Isotope, mass 82Se,100-200 kg208Tl: < 20 mBq/kg214Bi: < 300 mBq/kg

Backgroundin bb-foil

208Tl: < 2 mBq/kg214Bi: < 10 mBq/kg

8% Efficiency 30%

8% @ 3 MeV Energy resolution (FWHM) 4% @ 3 MeV

T1/2 > 2 x 1024 y<mn> < 0.3 – 0.8 eV

SensitivityT1/2 > 1-2 x 1026 y

<mn> < 40 – 100 meV

EN

tM

W

ayT

BGR

)(0

2/1

NEMO-3 successful experience allows to extrapolate tracko-calo technique on larger mass next generation detector to reach new sensitivity level.

20 modules, each of them hosts:

- 5 kg of source foil (82Se, 40mg/cm2)

- 2000-3000 Geiger channels

- 600 Calorimeter channels:

PVT Scintillator + 8’’ PMT

SuperNEMO basic design

SuperNEMO module

SuperNEMO is the favorite project to be hosted in the new LSM laboratory (hall A) planned to be opened at 2013

16

SuperNEMO demonstrator

SuperNEMO demonstrator (first module) being finalizing, which will: 1) Prove the concept2) Test 0nbb at level of KGC3) Start in 2012

Calorimeter R&DTracker R&D

Low background R&DSimulations

Source: 6.3 kg of 82Se

BiPo setup

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Seminář ÚČJF - Vít Vorobel 17

BiPo setup

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Aktivity MFF UK v NEMO-3/SuperNEMO• V úzké spolupráci s UTEF ČVUT

• NEMO-3• Simulace a návrh neutronového stínění• Koordinace výroby/dodávky nosné konstrukce detektoru (Transporta Chrudim)• Koordinace výroby/dodávky „Radon Trapping Facility“ (Hradec Králové)• Analýza dat 150Nd (excitovaný stav)

• SuperNEMO• Studie alternativní podoby kalorimetru (PD x PMT)• Optimalizace tvaru scintilátorů• Měření Rn• Testování scintilátorů

ecm

cMeVrqp

BBrqp5

/474.3

27.01.2009 NEMO3/SuperNEMO collaboration meeting, Prague

1911.9 12.5 13.7

13.9

14.113.811.8

12.7 11.5

20 mm

20 mm

Scintillator response vs irradiation position

91.5 88.6 85.5

87.3

89.9

91.988.7

90.6 92.5

Scintillatorposition scan Irradiated area 11.6 mm

FWHM @ 1 MeV, %

Peak position, ADC

Seminář ÚČJF - Vít Vorobel 20

Daya Bay Reactor Antineutrino Oscillation Experiment

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Seminář ÚČJF - Vít Vorobel 21

The Daya Bay Collaboration

North America (14)(54)BNL, Caltech, George Mason Univ., LBNL,

Iowa state Univ. Illinois Inst. Tech., Princeton, RPI, UC-Berkeley, UCLA, Univ. of Houston,

Univ. of Wisconsin, Virginia Tech., Univ. of Illinois-Urbana-Champaign

Asia (18) (88)IHEP, Beijing Normal Univ., Chengdu Univ. of Sci. and Tech., CGNPG, CIAE, Dongguan Polytech. Univ., Nanjing Univ.,Nankai Univ.,

Shandong Univ., Shenzhen Univ., Tsinghua Univ., USTC,

Zhongshan Univ., Hong Kong Univ.,Chinese Hong Kong Univ., National Taiwan Univ.,

National Chiao Tung Univ., National United Univ.

Europe (3) (9)JINR, Dubna, Russia

Kurchatov Institute, Russia

Charles University, Czech Republic

~ 150 collaborators

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Seminář ÚČJF - Vít Vorobel 22

?

13The Last Unknown Neutrino Mixing Angle

23 45

UMNSP MatrixMaki, Nakagawa, Sakata, Pontecorvo

1 0 0

0 cos23 sin23

0 sin23 cos23

cos13 0 e iCP sin13

0 1 0

e iCP sin13 0 cos13

cos12 sin12 0

sin12 cos12 0

0 0 1

1 0 0

0 e i / 2 0

0 0 e i / 2i

• What ise fraction of 3?• Ue3 is the gateway to CP violation in

neutrino sector:

U Ue1 Ue2 Ue 3

U1 U2 U 3

U1 U 2 U 3

0.8 0.5 Ue 3

0.4 0.6 0.7

0.4 0.6 0.7

?

atmospheric,accelerator

reactor,accelerator

0SNO, solar SK,KamLAND

12 ~ 32° 23 = ~ 45° 13 = ?

P( e) - P( e) sin(212)sin(223)cos2(13)sin(213)sinˉˉ

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Seminář ÚČJF - Vít Vorobel 23

ELm

ELm

Pdis 4sin2sincos

4sin2sin

2212

122

134

2132

132

Measuring 13 Using Reactor Anti-neutrinos

Electron anti-neutrino disappearance probability

Sin22q13 = 0.1Dm2

31 = 2.5 x 10-3 eV2

Sin22q12 = 0.825Dm2

21 = 8.2 x 10-5 eV2

Small oscillation due to q13

< 2 kmLarge oscillation due to q12

> 50 km

e disappearance at short baseline(~2 km): unambiguous measurement of 13

Osc. prob. (integrated over E n ) vs distance

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Seminář ÚČJF - Vít Vorobel 24Total length: ~3100 m

Daya BayNPP, 22.9 GW

Ling AoNPP, 22.9 GW

Ling Ao-ll NPP(under construction)

22.9 GW in 2011

295 m

81

0 m

465 m

900 m

Daya Bay Near site363 m from Daya BayOverburden: 98 m

Ling Ao Near site~500 m from Ling AoOverburden: 112 m

Far site1615 m from Ling Ao1985 m from DayaOverburden: 350 m

entrance

Filling hall

Mid site 873 m from Ling Ao1156 m from DayaOverburden: 208 m

Constructiontunnel

4 x 20 tons target mass at far site

Daya Bay: Powerful reactor close to mountains

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Seminář ÚČJF - Vít Vorobel 25

Detection of e

Time, space and energy-tagged signal suppress background events.

E Te+ + Tn + (mn - mp) + m e+ Te+ + 1.8 MeV

Inverse -decay in Gd-doped liquid scintillator:

0.3b® + Gd Gd* Gd + ’s(8 MeV) (t~30μs) + p D + (2.2 MeV) (t~180μs)

50,000b

nepe

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Seminář ÚČJF - Vít Vorobel 26

Antineutrino Detector

Cylindrical 3-Zone Structure separated by acrylic vessels:

I. Target: 0.1% Gd-loaded liquid scintillator, diameter=height= 3.1 m, 20 ton

II. g-catcher: liquid scintillator, 42.5 cm thick

III. Buffer shielding: mineral oil, 48.8 cm thick

vertex

14%~ , 14cm

(MeV)

E E

12.2%

13cm

With 192 PMT’s on circumference

and reflective reflectors on top and bottom:

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Seminář ÚČJF - Vít Vorobel 27

Inverse-beta SignalsAntineutrino Interaction Rate(events/day per 20 ton module)Daya Bay near site 840 Ling Ao near site 740 Far site 90

Delayed Energy SignalPrompt Energy Signal

MC statistics corresponds to a data taking with a single module at far site in 3 years.

Ee+(“prompt”) [1,8] MeVEn-cap (“delayed”) [6,10] MeV

tdelayed-tprompt [0.3,200] s

1 MeV 8 MeV

6 MeV 10 MeV

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Seminář ÚČJF - Vít Vorobel 28

Muon “Veto” System

Surround detectors with at least 2.5m of water, which shields the external radioactivity and cosmogenic background

Water shield is divided into two optically separated regions (with reflective divider, 8” PMTs mounted at the zone boundaries), which serves as two active and independent muon tagger

Augmented with a top muon tracker: RPCs

Combined efficiency of tracker > 99.5% with error measured to better than 0.25%

Resistive plate chamber (RPC)

Inner water shieldOuter water shield

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Seminář ÚČJF - Vít Vorobel 29

Backgrounds

DYB site LA site Far siteFast n / signal 0.1% 0.1% 0.1%

9Li-8He / signal 0.3% 0.2% 0.2%Accidental/signal <0.2% <0.2% <0.1%

Background = “prompt”+”delayed” signals that fake inverse-beta events

Three main contributors, all can be measured:

Background type Experimental Handle

Muon-induced fast neutrons (prompt recoil, delayed capture) from water or rock

>99.5% parent “water” muons tagged~1/3 parent “rock” muons tagged

9Li/8He (T1/2= 178 msec, b decay w/neutron emission, delayed capture)

Tag parent “showing” muons

Accidental prompt and delay coincidences Single rates accurately measured

Background/Signal:

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Seminář ÚČJF - Vít Vorobel 30

Daya Bay: Status and Plan• Ground Breaking Oct 07• CD-3 review comleted Spring 08• Surface Assembly Building occupancy March 09• Mini Dry Run Dec 09• Dry Run Spring 09• Daya Bay Near Hall ready for data taking 2010• All near and far halls ready for data taking 2011

0 1 2 3 4 5

0.01

0.02

0.03

0.04

Run Time (Years)

Se

nsi

tivity

Run Time (Years)

sin

2 2 1

30.01Goal:

sin2 2

13 (

90%

C.L

.)

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Seminář ÚČJF - Vít Vorobel 31

Testování RPC kosmickým zářením – IHEP Peking

24.03.2010

Kritéria testů: účinnost >95% singles (šum)< 0.8Hz/cm2 dark current< 10 μA/m2

Testováno 1600 ks RPC, odmítnuto 15%

Seminář ÚČJF - Vít Vorobel 32

谢谢你们 ！Děkuji za pozornost !

24.03.2010