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LENALow Energy Neutrino Astronomy

NOW 2010, September 6, 2010

Lothar Oberauer, TUM, Physik-Department

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Liquid Scintillators are well known as neutrino targets

Poltergeist ~ 1 t

BOREXINO ~ 300 t

KamLAND ~ 1000 t

Double-Chooz ~ 10 t

SNO+ ~ 1000 t

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What’s about a ~ 50 kt Detector ?

LENA – Low Energy Neutrino Astronomy

(~50 kt deep underground detector)

Hanohano

(~10 kt deep ocean detector)

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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

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LENA and proton decay High sensitivity to p -> K

(eff. ~ 68% instead 6% in SK

~ 5 x 1034 y) Sensitive to a variety of decay channels

“invisible” modes, e.g. n -> For e.g. p -> e+ we expect ~ 1033 y

(work in progress)T. Marrodan et al., Phys. Rev. D72, 075014 (2005)

L. Oberauer, TUM

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LENA and a galactic supernova

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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 detectorsL. Oberauer, TUM

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LENA and the Diffuse Supernova Background

• Excellent background rejection (ep->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) 023007

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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

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Tracking in a scintillator detector

HE particles create along their track a lightfront very similar to a Cherenkov cone.

Single track reconstruction based on: Arrival times of 1st photons at PMTs Number of photons per PMT

Sensitive to particle types due tothe 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

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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

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Study CERN – LENA at Pyhäsalmi (Finland) CERN - Pyhäsalmi 2288 km 5 years nu + 5 years anti-nu 1. Maximum @ 4.2 GeV Wide band beam 1 – 6 GeV 1.5 MW power Sensitivity on theta_13, CP-parameter,

mass hierarchyJ. Peltoniemi, Simulations of neutrino oscillations for a wide band beam from CERN to LENA, arXiv:0911.4876v1 [hep-ex]

L. Oberauer, TUM

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prelim

inary

CP

- p

has

e

Log( sin(2

Mass Hierarchy

> 3 Sigma

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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 eetransitions

L. Oberauer, TUM

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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

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LENA and Reactor neutrinos

At Frejus ~ 17,000 events per year High precision on solar oscillation

parameter: m2

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S.T. Petcov, T. Schwetz, Phys. Lett. B 642, (2006), 487

J. Kopp et al., JHEP 01 (2007), 053

L. Oberauer, TUM

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Scintillator R&D

atte

nuat

ion

leng

th

•Light yields

•Fluorescence times and spectra

•Attenuation lengths

•Scattering lengths

Development of an optical model for Monte-Carlo simulations

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PXE, C16H18

density: 0.99 kg/llight yield:

ca. 10.000 ph/MeVfluorescence decay: 2.6nsattenuation length: ≤12m

(purified)scattering length: 23m

+80% Dodecane, C12H26

density: 0.80 kg/llight yield: ca. 85%fluorescence decay slowerattenuation length: >12mscattering length: 33m

Solvent Candidates

LAB, C16-19H26-32

density: 0.86 kg/llight yield: comparablefluorescence decay: 5.2nsattenuation length: <20mscattering length: 25m

Detector diameter of 30m (or even more) is well feasible!

Fluorescence times (3-5ns) and light yield (200-500pe/MeV) depend on the solvent.

LAB is currently favored.

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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

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favoured option:

+ Tank Construction: 8 years

L. Oberauer, TUM

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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