v. sinev institute for nuclear researche...

V. SinevInstitute for Nuclear Researche RAS

Neutrino Geo Science 2010, Gran Sasso, 6-8 October

Collaboration

INR RAS (Moscow): I.R. Barabanov, G.V. Domogatsky, G.Ya. Novikova, V.V. Sinev, E.A. YanovichINR RAS (Baksan) : V.N. Gavrin, V.V. Kuz’minov

06/10/2010Neutrino Geo Science 2010, Gran

Sasso 2

Plan of Talk

IntroductionGeophysical theories. The composition of the Earth in comparison to the Sun and asteroids. Additional neutrino sourcesLooking for neutrino sources inside the EarthBaksan neutrino observatory RASLarge volume liquid scintillator detector at Baksan

06/10/2010 Neutrino Geo Science 2010, Gran Sasso 3

We know about our Sun structure and content more than about the Earth in spite of the mankind live on its surface


Sun


•Thermonuclear fusion reactions is the source of Sun energy

•It is proved by neutrino registration during last 60 years

•Experiments Cl-Ar, Ga-Ge (SAGE, Gallex, GNO), SNO, Super-Kamiokande, BOREXINO

«Photo»

of the Sun in neutrinos

(Super- Kamiokande)

Solar neutrinos energy spectra

06/10/2010 6Neutrino Geo Science 2010, Gran Sasso

Cl-Ar 0.81 MeVGa-Ge 0.233 MeV

BOREXINO ~0.2 MeV

Earth


•Known:

•The content of thin layer –

crust. Crust depth is 5- 60 km in comparison to Earth radius 6370 km. The

deepest hole drilled is ~12 km in depth.

•By seismic methods were found layers of the Earth.

•Unknown:

•The content and nature of layers.

•The source(s) of Earth thermal flux?

•The source of Earth magnetic field?

Geoneutrinos energy Spectra


Inverse beta-decay reaction threshold

1.806 MeV

•Radioactive isotopes decay is possible source of the Earth thermal flux (one of?)•In particularly radioactive families of 238U and 232Th•Beta emitters produce also antineutrinos•How many of these isotopes inside the Earth and where they placed in?•First success of geoneutrinos registration: KamLAND and BOREXINO

Anti-neutrino energy, E ν (MeV)

Eve

nts

/ 0.1

7MeV

1.8 2 2.2 2.4 2.6 2.8 3 3.2 3.4 0

5

10

15

20

25

30


Eve

nts

/ 0.1

7MeV

2 4 6 8 0

5

10

15

20


Eve

nts

/ 0.1

7MeV

1.8 2 2.2 2.4 2.6 2.8 3 3.2 3.4 0

5

10

15

20

25

30


Eve

nts

/ 0.1

7MeV

2 4 6 8 0

5

10

15

20

a b

(MeV)pE1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.60

20

40

60

80

100

120

(MeV)pE1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.60

20

40

60

80

100

120 KamLAND data best-fit osci.accidental

O16,n)αC(13

eνbest-fit Geo best-fit osci. + BG

eν+ best-fit Geo

0

20

40

[8]eνReference Geo Data - BG - best-fit osci.

Eve

nts

/ 0.2

MeV

1 TNU = 1 соб./1032

протонов

в

год

BOREXINO

3.9 +1.6 -1.3 соб./(год

100 т)



What we can understand when detecting geoneutrinos?

•Global content of U and Th in the Earth•Content U/Th in the core and in the mantle (comparing data from several detectors)•To test theories concerning the Earth inner parts structure

Earth structure


Crust: 7-10

km

oceanic, 30-60 km continental, ρ=~2.5-3.5

g/cm3

Upper mantle: ~30-660 km, ρ=~3.5-4

g/cm3

Lower mantle: ~660-2900 km, ρ=~5

g/cm3

Outer core, ~2900-5140 km, ρ=~10-11

g/cm3

Inner core, ~5140-6371 km, ρ=~12-13

g/cm3, t = 6000°

С

Standard theory


Earth core consists mainly of the iron.

Mantle is made of silicates. The crust consists of oxides.

Radioactive elements present only in the crust and partially in mantle.

Inside the Earth is hot

(t = 5000-6000°

С, thermal sources?). Measured thermal flux

~40 TW

Earth mass:

5.9736х1024

kg

Earth content: Fe (32.1%), O (30.1%), Si (15.1%), Mg (13.9%), S (2.9%), Ni (1.8%), Ca (1.5%), Al (1.4%), others

(1.2%)

Alternative theory (hydridic Earth

proposed by V.N. Larin)


The core consists of hidrides

of Si,

Mg, Fe and others

No mantle in understanding of standard theory

Radioactive elements were distributed homogeneously at the beginning, exist in the core like primordial content.

Inside the Earth is relatively

«cold»

(t = ~1000-2000°

С, thermal sources?). Measured thermal flux

40 TW

Earth mass:

5.9736х1024

kg

Earth content: Si (45%), Mg (31%), Fe (12%), Ca (3%), Al (2%), Na (1.5%),

O (1%),

C (0.3%), S (0.3%), H (4.5%), others

(<0.01%)

Hydridic Earth


Lithosphere: ~0-150 km, ρ=~2.5-4

g/cm3

oxides and silicates

Outer core, ~2900-5140 km, ρ=~10-11

g/cm3

metals with dissolved in them hydrogen

Inner core, ~

5140-6371 km, ρ= ~ 25

g/cm3, t ~ 2000°

С, metal

hydrides

Methalosphere: ~150-2900 km, ρ=~5

g/cm3

alloys and compounds

on base of

Si, Mg

and

Fe et al.


3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22Ionization potential, eV

Elements abundances at the Earth relative to the Sun

Ne

Ar

10

1

10-1

10-2

10-3

10-4

10-5

10-6

10-7

10-8

10-9

10-10

Xe Kr

NC

O

Ba

RbFeTi

L. N. Aller, The Abundance of the Elements,

Interscience Publishers, New York, London, 1961


3 4 5 6 7 8 9 10 11 12 13 14 150.01

0.10

1.00

10.00

100.00

Cs

Rb

K

Na

Cr

Ga

N

O

Cl

C

Ionization potential, eV

Elements abundances at the Moon relative to the Earth

Fe

Cr

Handbook of Geochemistry, Ed. K.H. Wedepohl et el., New York, Berlin, 1973.


Ionization potential, eV

Elements abundances at asteroid belt (meteorites) relative to the Earth

3 4 5 6 7 8 9 10 11 12 13

103

102

101

100

10-1

10-2

RbCs K

Li Al

Fe

AuS

Pt

Hg

Handbook of Elementary abundances in Meteorites, Ed. B. Maison, vol. 1, London, 1971

Large volume scintillation detector (or better the detector net) can discover neutrino sources inside the Earth

and test

geophysical theories.


Proposed and working detectors of geoneutrinos


KamLANDBOEXINO

SNO+Baksan

Hawaii

LENA

http://igppweb.ucsd.edu/~gabi/crust2.html

KamLAND. Japan. 1kt


BOREXINO Italy, LNGS. 300 t


SNO+ (Sudbury Neutrino Observatory). Canada. 1 kt


LENA (Low Energy Neutrino Astronomy). Pyhasalmi (Finland). 50-90 kt


Hano-Hano. Hawaii. 10 kt


Baksan. Russia, Caucasus. 5 kt


Neutrino Geo Science 2010, Gran Sasso

Target 5 kt

Veto

06/10/201006/10/2010 262606/10/2010 Neutrino Geo Science 2010, Gran Sasso 26

Geoneutrino effect at known sites

1 kt

(1032

Н)

SiteSite Mantovani Mantovani et al, 2004et al, 2004

Enomoto, Enomoto, 20052005

Sinev et Sinev et al., 2009al., 2009

Plus Plus higher sea higher sea levellevel

With the With the corecore

HawaiiHawaii 1122..55 13.413.4 15.9915.99 16.0316.03 2200..88

KamiokaKamioka 3344..88 36.536.5 33.233.2 33.433.4 3388..22

Gran SassoGran Sasso 4400..55 43.143.1 4411..77 4422..33 47.147.1SudburySudbury 4949..66 50.450.4 52.252.2 552.82.8 5757..55

PyhPyhääsalmisalmi 52.452.4 52.452.4 55.455.4 5555..77 6600..55

BaksanBaksan 5511..99 55.055.0 55.155.1 5757..00 6611.8.8

HimalayaHimalaya 60.060.0 -- 72.872.8 78.578.5 83.283.2

How to look for neutrino sources in the Earth?

1. To install neutrino detectors at contrast points (where there is prevalence of one source over others). Detector net.

2. To obtain information on neutrino direction.


MC simulation. Points of neutron scattering after appearance from inverse beta decay reaction


Capture point is shifted on

~2 cm (in liquid

scintillator) relatevely to the appearence point.

Angle distribution of neutrons from inverse beta decay


MC for SN antineutrinos coming along the zenith angle

M. Apllonio, A. Baldini, C. Bemporad et al., Phys. Rev. D61, 012001, 1999.

dLM+Cr = αLM dLM + (1 – αLM )⋅dCr ± σ/N1/2,where dLM = 1.2 cm, dCr = 0.29 cm and αLM = FLM / (FLM + FCr ) lower mantle fraction in total geoneutrino flux; N = 4000, achievable statistics,

σ/N1/2 = 0.32 cm.

0.00 0.20 0.40 0.60 0.80 1.000.00

0.50

1.00

1.50

αLM

d , cmZ

1.5

1

0.5

0

dz , cm

0 0.2 0.4 0.6 0.8 1αLM


G. Domogatsky, V. Kopeikin, L. Mikaelyan and V. Sinev, Phys. of At. Nucl., 69, iss. 11, 1894, 2006.

Baksan project



We propose to install large volume detector filled with liquid scintillator at Baksan neutrino observatory RAS (Russia, Caucasus).

Target volume 5000 m3.

Detector will be able to detect all possible antineutrino fluxes but mainly geoneutrinos .

Neutrino fluxes

GeoneutrinosGeoreactor (if exist)Antineutrinos and neutrinos from SN burstRelic neutrinos as remnants of SN explosions in the pastSolar neutrinosReactor antineutrinos


Rates measured by the detector at Baksan


Total positron spectrum of positrons from inverse beta decay in the detector


geoneutrino georeactorSN

104

103

102

101

100

10-1

10-2

104

103

102

101

100

10-1

10-2

1 10 Енабл.

, МэВ

SN relic neutrinos

atm.

Счет,

МэВ

-1год-

1

Счет,

МэВ

-1

Power nuclear reactors background at possible detector sites


0 1 2 3 4 5 6 7 80

10

20

0 1 2 3 4 5 6 7 80

1

2Baksan: 40.4; 2003 km Hawaii: 4.7; 7483 km

0 1 2 3 4 5 6 7 80

200

400Kamioka: 928; 227 km

0 1 2 3 4 5 6 7 80

20

40 G-Sasso: 111; 1189 km

0 1 2 3 4 5 6 7 80

40

80Sudbury: 197.6; 667 km

0 1 2 3 4 5 6 7 80

20

40 Pyhasalmi: 87.4; 1245 km

SN e, μ and τ antineutrino spectra


0 20 40 60 80 100Visible energy, MeV

0

20

40

60

80

even

ts/M

eV

b

0 20 40 60 80 100Visible energy, MeV

0

20

40

60

even

ts/M

eV

a

Normal mass hierarchy Inverted mass hierarchy

sinsin22θθ

1313

>10>10--33

Counting rate for SN at a distance of 10 kpc (4х1032

protons)

Reaction Reaction No No oscillationsoscillations

LMA MSWLMA MSWsinsin22θθ

1313

>10>10--33

LMA MSWLMA MSWsinsin22θθ

1313

<10<10--55

11571157 14791479 1479147914.414.45.85.8

35.535.5132132

35.535.593.593.5

236236 236236 236236

70.670.6 62.262.2 61.461.4


νe + p → e+

+ nνe + 12C → 12B +e+νe + 12C → 12N +e-

Σ

12C (νi , νi ’)12C +γ

Σ

(νi + e-

→ νi ’ + e-

)

Geoneutrino etc. rates in full scale detector at Baksan

Source Rate, ev./year/5 kt

Geoneutrino 220-250

Georeactor 80-260

Nuclear power reactors

160

Total: 460-670


What is the Baksan neutrino observatory today ?


View on the Baksan valley from Google


Village Neutrino

Mount Andyrchi

Mount Elbrus

43° 14’ N

42° 43’ E

Mount Andyrchi


Working setups at BNO:


Baksan underground neutrino scintillation telescope, ~300 m.w.e.Ga-Ge experiment (SAGE) ~4800m.w.e.Low background laboratory 4800 m.w.e.Set up «Carpet» on the mountain slope.Gravitational antenna


Neutrinovillage

EAS array“Andyrchy”

Tunnel entrance

? ?? ? ? ? ?

? ? ? ? ? ? ?? ? ? ? ? ? ?? ? ? ? ? ? ?

? ? ? ? ?? ? ?

Neutrinovillage

“Karpet-2”EAS array

Tunnel entrance

1

3

4

5

6

7

2

? ?? ? ? ? ?

? ? ? ? ? ? ?? ? ? ? ? ? ?? ? ? ? ? ? ?

? ? ? ? ?? ? ?

1,7 1,7 - Low-background chambers2 - BUST3 - Laser interferometer4 - Acoustic gravitational antenna 5 - Geophysics laboratory6 - Ga-Ge Neutrino Telescope (SAGE)

* - EAS array “Andyrchi”

? ?? ? ? ? ?

? ? ? ? ? ? ?? ? ? ? ? ? ?? ? ? ? ? ? ?

? ? ? ? ?? ? ? villagevillage

*

Baksan neutrino observatoryBaksan neutrino observatoryMt. Andyrchi

SAGE 4800 m.w.e.

Place where we suppose to construct the detector 4800 m.w.e.

Neutrino telescope 300 m.w.e.


SAGE: tanks filled with metallic gallium


Baksan neutrino underground telescope

Satus of Baksan project


Scinillator based on LAB + PPO (4 g/l) + bisMSB (0.05 g/l)

Good long term stability (>1 year)There were tested probes of scintillator doped with Gd in complex of TMHA (trimethilhexan-acid). They demonstrate good long term stability.Gd is needed for better coordinate definition.


PMTs: 10” Hammamatsu R7081


The same PMTs that are used in

Double Chooz expriment

Total amount: 6000

Conclusion and outlook

Baksan neutrino observatory RAS is attractable place for installing geoneutrino detector (existing infrastructure, high counting rate, low nuclear reactors rate).The detector installed at BNO RAS could be a part of international detector net for geoneutrinos. It does not sensitive to the proton decay but may be a part of some complicated detector consisted of a number of large volume detectors (its volume can be accounted for looking for proton decay).

06/10/2010 Neutrino Geo Science

2010, Gran Sasso 50

continuation

We are preparing the proposal for the experiment at BNO RAS.Looking for the foundation (Russian fund for basic researches and others)Negotiations with geologists on making researches of rocks solidity. If it may be possible to dig a hole in diameter 30-35 m

06/10/2010 51Neutrino Geo Science

2010, Gran Sasso

v. sinev institute for nuclear researche...

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