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Application of neutrino spectrometry. 1) Solar neutrino detection. 2) Supernovae neutrino detection. 3) Cosmic and atmospheric neutrino detection. 4) Neutrino oscillation studies. 5) Detection of neutrinos from Earth interior. 6) Relict neutrino detection. Sun from SOHO probe. - PowerPoint PPT Presentation
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Application of neutrino spectrometry
1) Solar neutrino detection
2) Supernovae neutrino detection
3) Cosmic and atmospheric neutrino detection
4) Neutrino oscillation studies
Supernovae 1987A remnantNeutrino detector ANTARESat Mediterranean See
Sun from SOHO probe
5) Detection of neutrinos from Earth interior
6) Relict neutrino detection
Study of solar neutrinos
neutrino energy [MeV]
Neu
trin
o fl
uen
ce [
cm-2s-1
]
Spectrum of solar neutrinos calculated by J. Bahcalla
Present information:1) Solar neutrino are produced 2) Significant difference between prediction and observation → sign of new physics (neutrino oscillations)
Future information based on neutrinos:1) Accurate sizes of Sun central regions, where fusion reactions runs2) Present picture of Sun interior (photons travel through sun long time) – prediction of future Sun behavior3) Temperature of central regions of Sun 4) Ratios between different types of fusion reactions
Sun from SOHO probe
Big amount of electron neutrino is produced during pp and CNO cycle
4p → 4He + 2e+ + 2νe
Study of supernovae neutrinos
Final stage of massive star – collapse and supernovae explosionLarge part of energy releases in the form of neutrino during two phases:1) Beginning – during neutron creation by electron capture only electron neutrino:
p + e- → n + νe
2) All types of neutrino and antineutrino with statistical distribution (1/6 on one type) with mean energy 10 – 15 MeV. Energy spectrum → Fermi distribution kT ≈ 3 – 6 MeV
Supernovae SN1987A
Relation between neutrino energy and time of its arrival
Distance of 150 000 light years
Present information (supernovae SN1987A): Confirmation of neutrino creation Ordinary agreement with assumption Closeness of neutrino velocity to light velocity, limitation on neutrino rest mass Determination of limitation on neutrino lifetimePossible future information (we are waiting on near supernovae): Confirmation of models of supernovae explosion Properties of hot and very dense matter Observation of supernovae shielded by galactic matter
Cosmic ray neutrinos
Primary component: particle with high energy (up to ~ 1011 GeV – present accelerators ~ 104 GeV), protons and nuclei are the biggest part, also neutrinos and antineutrins νe, νμ a ντ are present. Isotropic distribution – they come from all directions Origin: more distant undistinguishable sources (supernovae, active galaxy nuclei, collapsing objects …)
Possible future information: Information about processes and sources with big amount of energy (gamma burst sources) Not distorted data about region covered by dense clouds of matter Neutrino path is not influenced by magnetic fields and they are not absorbed Study of nature of cosmic phenomena
Secondary component: Collisions of cosmic ray particles and nuclei with atmospheric nuclei → many hadrons → many mesons π among them: π + → μ+ + νμ π - → μ- + anti -νμ
└→ e+ + νe + anti-νμ └→ e- + anti-νe + νμ Intensive source of neutrino and antineutrino νμ and νe
ratio between numbers of νμ and νe is R(νμ/νe) = 2 also intensive source of muons Atmospheric shower
Distribution of directions, from which single neutrinos came – random distribution –Point like sources were not found – also correlation with gamma bursts were not found
Spectrum of neutrinos agrees with predictionfor atmospheric neutrinos
Results of AMANDA detector
Nebula NGC6543(Hubble telescope)
Active galaxy
Studies of neutrino oscillation
2
1e
cossin
sincos
)L/Em27.1(sin2sin)P( 222e
As example – oscillation of anti νμ and anti νe:
Probability of muon antineutrino to electron is:
where Δm2 = |m12 – m2
2| [eV2], L – distance at meters [m] Eν – neutrino energy [MeV]
Neutrino wave function is mixture of different states (νe, νμ, ντ) .
d
Probability, that at distance d we find anti νμ is and anti νe :)(P )(P e
Oscillation were observed: 1) Solar neutrinos (large distances) 2) Nuclear power station 3) Secondary cosmic rays 4) Accelerator - detector
Experiment EMIN
[MeV]
Experiment[SNU]
Model[SNU]
Exp./Mod.
Kamiokande 7 0.47(2) 1.00(17) 0.47
Homestake (Cl) 0.8 2.56(23) 7.7(12) 0.33
GALEX 0.2 74(7) 129(8) 0.57
SAGE 0.2 75(8) 129(8) 0.58
Solar neutrinos
Derivation of Δm2 (νe ↔ νμ) Δm2 ~ 7(4)∙10-5 eV2
Relation betweenΔm2 and θ values
Experiment GALEX
Detector KAMLAND Measured and simulated spectrumof antineutrinos
Oscillation data measured using different reactors
Measurement of reactor antineutrino oscillation
Δm2 =7,9(6)∙10-5 eV2νμ ↔ νeDetection of antineutrino
Time variation given by changes of nuclear reactors power
Secondary cosmic ray
νμ ↔ ντ Δm2 =(1-3)∙10-3 eV2
Accelerator – detector experiment
K2K experiment – observation of 108 neutrinos – prediction of 151(11) neutrinos
νe - isotropic distributionνμ - úbytek
The best fit with oscillation
Neutrino spectrum detectedby K2K experiment
Region of suitable Δm2 a sin22θ values
Angular distribution of cosmicneutrinos from Kamiokande
Geoneutrinos
Antineutrinos from 238U and 232Th decay
Decay of 238U and 232Th impeachable for hot earth core and plate tectonics
First observation – project KamLAND: 4 – 40 detected geoantineutrinos
Agree with model predictions about amount of uranium and thorium in earth crust and core
geoantineutrinos
reactor antineutrinos
background
13C(α,n)16O
Project KamLAND – study of antineutrino oscillations by means of reactor
Antineutrinos from project KamLAND(corrected on oscillations)
Larger detector farer from reactors makes possible study of antineutrinos with such accuracy, which is needed for some geophysical models exclusion
Thermal flow: Total ~ 40 TW radionuclides ~ 19 TW(U,Th,K)
Relict neutrinos
are produced during early stage of universe t ~ 1s (t ~ 300 000 years for relict photons), present temperature of neutrinos is T ≈ 1,9 K (photons T ≈ 3,1 K)
For energies E > 1 MeV different types of neutrinos are in the equilibrium:
iiee where i = e, μ, τ
For lower energies neutrinos do not interact with rest of matter – freeze out occurs
Very low energy → very big problems with detection
Possibility of detection (only hypothetical up to now):
1) Processes, which do not need energy – neutrino initiates beta decay of nucleus: νe + n → p+ + e- Electron energy > decay energy of nucleus → peak in the electron spectrum under end of Fermi graph (very weak). Measurement as during neutrino mass studies – necessity to find proper nuclei and transitions, number of decays initiated by relict neutrinos was should be not negligible. Necessity to improve parameters of electron spectrometers. Problems with the natural background.
2) Interaction of accelerated particles – energy is delivered by accelerated particles. Choice of proper parameters for sufficient probability of interaction – problem with background, necessity of high intensity and stability of accelerator beam. 3) Interaction of very energetic neutrinos of cosmic rays:such Eν, that centre of mass energy is equal to rest mass of Z boson during collision with relict neutrino MZ = 100 GeV (1012 – 1016 GeV – real value depends on neutrino mass) → resonce increasing of interactions with relict neutrinos occurs → minimum in the energy spectrum of high energy of cosmic neutrinos