1 LENA Low Energy Neutrino Astronomy NOW 2010, September 6, 2010 Lothar Oberauer, TUM, Physik-Department

2 Liquid Scintillators are well known as neutrino targets Poltergeist ~ 1 t BOREXINO ~ 300 t KamLAND ~ 1000 t Double-Chooz ~ 10 t SNO+ ~ 1000 t

3 What’s about a ~ 50 kt Detector ? LENA – Low Energy Neutrino Astronomy (~50 kt deep underground detector) Hanohano (~10 kt deep ocean detector)

4 LENA Physics Goals Proton Decay Galactic Supernova Burst Diffuse Supernova Neutrino Background Long baseline neutrino oscillations Solar Neutrinos Geo neutrinos Reactor neutrinos Neutrino oscillometry Atmospheric neutrinos Dark Matter indirect search L. Oberauer, TUM

5 LENA and proton decay High sensitivity to p -> K (eff. ~ 68% instead 6% in SK  ~ 5 x y) Sensitive to a variety of decay channels “invisible” modes, e.g. n ->  For e.g. p -> e +   we expect ~ y (work in progress) T. Marrodan et al., Phys. Rev. D72, (2005) L. Oberauer, TUM

6 LENA and a galactic supernova

7 LENA and a Galactic Supernova Burst Antielectron spectrum with high precision Electron flux with ~ 10 % precision Total flux via neutral current reactions Separation of SN models Spectroscopy of all  flavors Sensitivity on deleptonization neutrinos Time evolution of neutrino burst Details of SN gravitational collapse Chance to separate low/high   and mass hierarchy (normal/inverted) Coincidence with gravitational wave detectors L. Oberauer, TUM

8 Separation of SN models ? Yes! Possible independent from oscillation model due to neutral current reactions in LENA TBPKRJLL 12-C: Nu-p: for 8 solar mass progenitor and 10 kpc distance

9 LENA and the Diffuse Supernova Background Excellent background rejection ( e p->e + n) Energy window 10 to 30 MeV. High efficiency (100% with 50 kt target) High discovery potential in LENA ~2 to 20 events per year are expected (model dependent) L. Oberauer, TUM M. Wurm et al., Phys.Rev.D 75 (2007)

10 LENA and long baseline neutrino oscillations Separation between e- and  -like events Pulse shape discrimination (risetime, width) Track reconstruction Muon decay  e  Work in progress electrons (1.2 GeV) muons (1.2 GeV) L. Oberauer, TUM

11 Tracking in a scintillator detector HE particles create along their track a light front very similar to a Cherenkov cone. Single track reconstruction based on:  Arrival times of 1 st photons at PMTs  Number of photons per PMT Sensitive to particle types due to the ratio of track length to visible energy. Angular resolution of a few degrees, in principal very accurate energy resolution. Work under progress for LENA and scintillator LBNE option for DUSEL -- J. Learned, N. Tolich... Monte- Carlo-study

12 CNGS neutrino induced muons in BOREXINO CERN 770km Direction from CERN (azimuth = 0 degree) real Data – no Monte-Carlo ! BOREXINO is NOT optimized for tracking ! Water Cherenkov Scintillator

13 Study CERN – LENA at Pyhäsalmi (Finland) CERN - Pyhäsalmi 2288 km 5 years nu + 5 years anti-nu GeV Wide band beam 1 – 6 GeV 1.5 MW power Sensitivity on theta_13, CP-parameter, mass hierarchy J. Peltoniemi, Simulations of neutrino oscillations for a wide band beam from CERN to LENA, arXiv: v1 [hep-ex]arXiv: v1 L. Oberauer, TUM

14 preliminary L. Oberauer, TUM

15 preliminary CP - phase  Log( sin(2  Mass Hierarchy > 3 Sigma

16 LENA and Solar Neutrinos High statistics in 7-Be (~ 5400 events per day) Search for small time fluctuations CNO and pep  events per day) Very sensitive test of MSW effect CC and NC measurements of 8-B Search for spectrum deformation Search for non-standard interactions Search for solar e  e  transitions L. Oberauer, TUM

17 LENA and Geo-neutrinos LENA is the only detector within Laguna able to determine the geo neutrino flux In LENA we expect between 300 to 3000 events per year (“best bet” ~ 1500 / year) Good signal / background ratio most significant contribution can be subtracted statistically Separation of geological models together with other detectors L. Oberauer, TUM

18 LENA and Reactor neutrinos At Frejus ~ 17,000 events per year High precision on solar oscillation parameter:  m 2 12     S.T. Petcov, T. Schwetz, Phys. Lett. B 642, (2006), 487 J. Kopp et al., JHEP 01 (2007), 053 L. Oberauer, TUM

19 Scintillator R&D attenuation length Light yields Fluorescence times and spectra Attenuation lengths Scattering lengths Development of an optical model for Monte- Carlo simulations

20 PXE, C 16 H 18 density: 0.99 kg/l light yield: ca ph/MeV fluorescence decay:  2.6ns attenuation length: ≤12m (purified) scattering length: 23m +80% Dodecane, C 12 H 26 density: 0.80 kg/l light yield: ca. 85% fluorescence decay slower attenuation length: >12m scattering length: 33m Solvent Candidates LAB, C H density: 0.86 kg/l light yield: comparable fluorescence decay:  5.2ns attenuation length: <20m scattering length: 25m  Detector diameter of 30m (or even more) is well feasible!  Fluorescence times (3-5ns) and light yield ( pe/MeV) depend on the solvent.  LAB is currently favored.

21 Pre-feasibility study for LENA at Pyhäsalmi (TUM and company Rockplan, Finland) Depth at 1400 m – 1500 m possible ! Geological study completed Vertical detector position Logistics (Vent, Electricity, etc.) considered Construction time of cavern ~ 4 years 1st costs estimate for the whole project Tank feasibility study (accomplished May 2010) L. Oberauer, TUM

22 favoured option: + Tank Construction: 8 years L. Oberauer, TUM

23 Conclusions Scintillator techniques for neutrino physics are very important Reactor-, Solar-, Geo-neutrino experiments Future: Extension to DSNB, Supernova-, Proton-Decay, Long-Baseline -Oscillations Rich R&D-program still on-going First feasibility studies successfully accomplished “White paper” under preparation L. Oberauer, TUM

24 Log (osc. Amplitude) CP – violating parameter Detection signifigance (chi) > 3 sigma preliminary L. Oberauer, TUM

25 Solar Neutrinos and LENA  e  e and 13 C + e  13 N + e

26 Sensitivity on U, Th Energy threshold 1st detection of Geo-neutrinos in KamLAND in 2005 (1kt liquid scintillator detector) arbitrary units

27 Signal & Backgrounds in LENA ~ 1500 per year signal ~ 240 per year in [1.8 MeV – 3.2 MeV] from reactor neutrinos < 30 per year due to 210 Po alpha -n reaction on 13 C (Borexino purity assumed) ~ 1 per year due to cosmogenic background ( 9 Li - beta-neutron cascade) K. Hochmuth et al., Astropart.Phys. 27 (2007) Can be statistically subtracted