LENA Low Energy Neutrino Astrophysics F von Feilitzsch, L. Oberauer, W. Potzel Technische Universität München LENA Delta

LENA (Low Energy Neutrino Astrophysics) Idea: A large (~30 kt) liquid scintillator underground detector for Galactic supernova neutrino detection Relic supernovae neutrino detection Terrestrial neutrino detection Search for Proton Decay Solar Neutrino Spectroscopy Neutrino properties artificial neutrino sources

P - decay event Scintillator: PXE, non hazard, flashpoint 145° C, density 0.99, Light absorption L= 12m, ultrapure (as proven in Borexino design studies) N pe ~ 100 / MeV beta

Possible locations for LENA ? Underground mine ~ 1450 m depth, low radioactivity, low reactor  background ! Access via trucks

loading of detector via pipeline transport of 30 kt PXE via railway no security problem with PXE ! no problem for excavation standard technology (PM-encapsulation, electronics etc.) LENA is feasible in Pyhäsalmi !

Pylos (Nestor Institute) in Greece, on the Cern Neutrino beam (off axis) 1500 km

Construction at a convinient site transportation to phylos in the sea sinking to apropriate depth density of whole construction = 1

Galactic Supernova neutrino detection with Lena (ca events for 30 kt) Electron Antineutrino spectroscopy ~ 65 Electron spectroscopy ~ 65 ~ 4000 and ~ 2200 Neutral current interactions; info on all flavours ~ 4000 and ~ 2200 ~7800 ~ 480 Event rates for a SN type IIa in the galactic center (10 kpc)

Supernova neutrino luminosity (rough sketch) Relative size of the different luminosities is not well known: it depends on uncertainties of the explosion mechanism and the equation of state of hot neutron star matter T. Janka, MPA

Visible proton recoil spectrum in a liquid scintillator all flavors     and anti-particles dominate J. Beacom, astro-ph/

SNN-detection and neutrino oscillations with LENA Dighe, Keil, Raffelt (2003) Modulations in the energy spectrum due to matter effects in the Earth

Scintillator good resolution Water Cherenkov Dighe, Keil, Raffelt (2003) SNN SNN-detection and neutrino oscillations Modulations in the energy spectrum due to matter effects in the Earth

Preconditions for observation of those modulations SN neutrino spectra e and  are different distance L in Earth large enough very good statistics very good energy resolution

LENA and relic Supernovae Neutrinos SuperK limit very close to theoretical expectations Threshold reduction from ~19 MeV (SuperK) to ~ 9 MeV with LENA Method: delayed coincidence of e p  e n Low reactor neutrino background ! Information about early star formation period - +

SNR No background for LENA ! Jap. Reactors in SK Reactor bg LENA ! Europ. km Atmospheric neutrinos LENA SNR rate: ~ 6 counts/y

Solar Neutrinos and LENA: Probes for Density Profile Fluctuations (p-modes)! 7-Be ~200 / h LENA Balantekin, Yuksel TAUP 2003 hep- ph/

terrestrial neutrinos in LENA. what is the source of the terretrial heat flow. what is the source of the terretrial heat flow? What is the contribution from radioactivity? How much U, Th is in the mantel? is there a TW reactor in the center of the earth? Where is the U, Th

Heat flow from the earth Measured:   80 mW / m 2 Integral: H E  4 x W = 40 TW (uncertainty ~20%): This corresponds to 10 4 nuclear power plants!

The crust and mantel may be analyzed directly. Theory: U, K und Th may be“lithophil”, may accumulate in the continental crust. ~30 km crust may content as much as 300 km of mantel. U, Th in lower part of mantel presently estimated by extrapolation from upper mantel. Where is U, Th? U In the (kont.) crust M c (U)  ( )10 17 kg. Still higher uncertaities for mantel: ? M m (U)  ( )10 17 Kg ? crust Upper mantle

KAMLAND: a first insight to terrestrial neutrinos 6 months of data N(Th+U) = 9  6* N(Th+U) = 9  ν e <2,6 ν e <2,6 MeV Uncertainty dominated by reactors _

Proton Decay and LENA Proton Decay and LENA p K p K SUSY This decay mode is favoured in SUSY theories The primary decay particle K is invisible in Water Cherenkov detectors It and the K-decay particles are visible in scintillation detectors Better energy solution => further reduces background +

P  K + event structure: T (K + ) = 105 MeV    nsec K +      63.5 %) K +      T (  + ) = 152 MeV T (  + ) = 108 MeV electromagnetic shower E = 135 MeV    e +  s)         e +  s)       MeV)    e +  s)    e +  s)

3 - fold coincidence !3 - fold coincidence ! the first 2 events are monoenergetic !the first 2 events are monoenergetic ! use time- and position correlation !use time- and position correlation ! How good can one separate the first two events ?....results of a first Monte-Carlo calculation

K  time (nsec) K  P decay into K and Signal in LENA

Background Rejection : mono energetic K- and  -signal! position correlation pulse-shape analysis (after correction on reconstructed position)

SuperKamiokande % ) SuperKamiokande has 170 background events in 1489 days (efficiency 33% ) LENA ~ 5 / y LENAIn LENA, this would scale down to a background of ~ 5 / y and after PSD-analysis this could be suppressed in LENA to ~ 0.25 / y~ 70% ~ 0.25 / y ! (efficiency ~ 70% )   a few years K-decayA 30 kt detector (~ protons as target) would have a sensitivity of   a few years for the K-decay after ~10 years measuring time SUSY SU(5)K-decay dominant10 29 y to yThe minimal SUSY SU(5) model predicts the K-decay mode to be dominant with a partial lifetime varying from y to y ! SK actual best limit from SK :  6.7 x y (90% cl)

LENA LENA a new observatory complementarely to high energy neutrino astrophysics fundamental impact on e.g. geophysics, astrophysics, neutrino physics, proton decay Pyhäsalmi ) feasibility studies very promising (Pyhäsalmi ) costs ca M€ (30KT) make it bigger = longer, several modules

...some more aspects of Lena Complementary to high energy neutrino astronomy Long term (~decades) experiment

Electron antineutrtino detection from artificial ß-decay sources Delayed coincidence => background rejection ν e + p => n +e 200μs n + p => D +2,2 MeV Remaining dominant background from fast n  pulse shape discrimination, Veto by H 2 O cerencov shield Self shielding of scitillator + _

Δ ~ MeV

Burn up of U in PWR (Gösgen)

Example: ν e Spectrum as a function of burn up (Gösgen Reaktor) _

Expected rates in LENA 50 KT 1 1GW reactor (with oscillations) Is this enough for identification of Pu production? Shape of 235U/239Pu 20% E(ν e ) =5 MeV after full burn up 100 events after 3 months _

LENA up to 100 KT may be movable Go to the source (Total density of LENA may be = 1) Similar to size of oil tanker or submarine For test of burn up in reactor Low energy threshold very helpful For background rejection (cosmic rays) at shalow depths puls shape discrimination useful (Fast neutron background in BOREXINO<< 1 event/a 100T)