Probing the Earth's interior with a large-volume liquid scintillator detector

A future large-volume liquid scintillator detector would provide a high-statistics measurement of terrestrial antineutrinos originating from $\beta$-decays of the uranium and thorium chains. In addition, the forward displacement of the neutron in the detection reaction $\bar\nu_e+p\to n+e^+$ provides directional information. We investigate the requirements on such detectors to distinguish between certain geophysical models on the basis of the angular dependence of the geoneutrino flux. Our analysis is based on a Monte-Carlo simulation with different levels of light yield, considering both unloaded and gadolinium-loaded scintillators. We find that a 50 kt detector such as the proposed LENA (Low Energy Neutrino Astronomy) will detect deviations from isotropy of the geoneutrino flux significantly. However, with an unloaded scintillator the time needed for a useful discrimination between different geophysical models is too large if one uses the directional information alone. A Gd-loaded scintillator improves the situation considerably, although a 50 kt detector would still need several decades to distinguish between a geophysical reference model and one with a large neutrino source in the Earth's core. However, a high-statistics measurement of the total geoneutrino flux and its spectrum still provides an extremely useful glance at the Earth's interior.Comment: 21 pages, 9 figures. Minor changes, version accepted for publication in Astroparticle Physic

Nuclear physics for geo-neutrino studies

Geo-neutrino studies are based on theoretical estimates of geo-neutrino spectra. We propose a method for a direct measurement of the energy distribution of antineutrinos from decays of long-lived radioactive isotopes. We present preliminary results for the geo-neutrinos from Bi-214 decay, a process which accounts for about one half of the total geo-neutrino signal. The feeding probability of the lowest state of Bi-214 - the most important for geo-neutrino signal - is found to be p_0 = 0.177 \pm 0.004 (stat) ^{+0.003}_{-0.001} (sys), under the hypothesis of Universal Neutrino Spectrum Shape (UNSS). This value is consistent with the (indirect) estimate of the Table of Isotopes (ToI). We show that achievable larger statistics and reduction of systematics should allow to test possible distortions of the neutrino spectrum from that predicted using the UNSS hypothesis. Implications on the geo-neutrino signal are discussed.Comment: 8 pages RevTex format, 8 figures and 2 tables. Submitted to PR

International Conference on Topics in Astroparticle and Underground Physics (TAUP 2011)

The 12th edition of the International Conference on Topics in Astroparticle and Underground Physics (TAUP 2011) was held 5–9 September 2011 in Munich (and for the first time in Germany). It was organized by the Max Planck Institute for Physics (MPP), the Technical University Munich (TUM) and the Cluster of Excellence 'Origin and Structure of the Universe'. The conference was held in the 'Künstlerhaus', a traditional downtown location for artistic festivities. The meeting attracted 317 participants (61 of which were women) from 29 countries, see figure below. The topics covered by the meeting were Cosmology and particle physics, Dark matter and its detection, Neutrino physics and astrophysics, Gravitational waves and High-energy astrophysics and cosmic rays, and the various interfaces between these areas. The scientific sessions consisted of five mornings of plenary talks, four afternoons of parallel sessions, and an evening poster session. The co-founder of the conference series, Alessandro Bottino, has decided to retire from the position of chairman of the TAUP Steering Committee after the completion of TAUP 2011. On behalf of all followers of this series, we thank him for having started these inspiring events and his many years of dedicated service. We thank all speakers, conveners and participants as well as the members of the organizing, steering and international advisory committee for making this a successful and memorable meeting. Lothar Oberauer, Georg Raffelt, Robert Wagner Proceedings editors ##IMG## [http://ej.iop.org/images/1742-6596/375/00/001001/figure.jpg] {Figure ----- -- Committees ----- -- International Advisory Committee ----- -- G Anton -- University of Erlangen ----- -- E Aprile -- Columbia University ----- -- M Baldo-Ceolin -- University of Padova ----- -- R Battiston -- University of Perugia & INFN ----- -- L Bergström -- University Stockholm ----- -- R Bernabei -- University of Rome 'Tor Vergata' ----- -- A Bettini -- LSC Canfranc ----- -- P Binetruy -- APC Paris ----- -- J Blümer -- Karlsruhe Institute of Technology ----- -- B Cabrera -- Stanford University ----- -- A Caldwell -- Max Planck Institute for Physics ----- -- M Chen -- Queens University ----- -- E Coccia -- University of Rome 'Tor Vergata' ----- -- K Danzmann -- Max Planck Institute for Gravitational Physics ----- -- S Dodelson -- Fermilab ----- -- G Domogatsky -- INR Moscow ----- -- E Fiorini -- Università di Milano Bicocca & INFN ----- -- K Freese -- University of Michigan ----- -- M Fukugita -- ICRR Tokyo ----- -- T Gaisser -- University of Delaware ----- -- G Gerbier -- CEA Saclay ----- -- F Halzen -- University of Wisconsin ----- -- W Haxton -- LNBL & UC Berkeley ----- -- J Hough -- Glasgow University ----- -- E Komatsu -- University of Texas ----- -- E Katsavounidis -- Massachusetts Institute of Technology ----- -- M Lindner -- Max Planck Institute for Nuclear Physics ----- -- K Lesko -- LBNL & UC Berkeley ----- -- A McDonald -- Queens University & SNO Laboratory ----- -- H Murayama -- IPMU Tokyo & UC Berkeley ----- -- A Olinto -- University of Chicago ----- -- L Resvanis -- University of Athens ----- -- A Rubbia -- ETH Zurich ----- -- S Sarkar -- University of Oxford ----- -- A Smirnov -- ICTP Trieste ----- -- N Smith -- SNO Laboratory ----- -- C Spiering -- DESY Zeuthen ----- -- N Spooner -- University of Sheffield ----- -- Y Suzuki -- ICRR Tokyo ----- -- M Teshima -- Max Planck Institute for Physics ----- -- J W F Valle -- IFIC & University of Valencia ----- -- L Votano -- LNGS ----- -- E Waxman -- Weizmann Institute ----- -- J Wilkerson -- University of North Carolina ----- ----- -- TAUP Steering Committee ----- -- F T Avignone -- University of South Carolina ----- -- B C Barish -- Caltech ----- -- E Bellotti -- University of Milan Bicoccia & INFN ----- -- J Bernabeu -- University of Valencia ----- -- A Bottino -- University of Turin & INFN (chair) ----- -- N Fornengo -- University of Turin & INFN ----- -- T Kajita -- ICRR Tokyo ----- -- C W Kim -- Johns Hopkins University & KIAS ----- -- V Matveev -- INR Moscow ----- -- G Raffelt -- Max Planck Institute for Physics ----- -- D Sinclair -- University of Carleton ----- -- M Spiro -- CEA Saclay ----- ----- -- Parallel Session Conveners ----- -- Dark Matter – Candidates and Searches ----- -- J-C Lanfranchi -- Technische Universität München ----- -- T Marrodán Undagoitia -- University of Zurich ----- -- T Bringmann -- Universität Hamburg ----- ----- -- Cosmology ----- -- J Weller -- Ludwig-Maximilians-Universität München ----- -- S Hannestad -- University of Aarhus ----- ----- -- Double Beta Decay, Neutrino Mass ----- -- M Hirsch -- IFIC/CSIC - University of Valencia ----- -- A Giuliani -- CNRS Orsay ----- ----- -- Neutrino Oscillations ----- -- T Lachenmaier -- Universität Tübingen ----- -- F Suekane -- Tohoku University ----- ----- -- Low-Energy Neutrinos (Geo, Solar, Supernova) ----- -- A Dighe -- TIFR Mumbai ----- -- M Chen -- Queen's University ----- -- M Wurm -- Universität Hamburg ----- ----- -- Gravitational Waves ----- -- E Coccia -- University of Rome Tor Vergata and INFN ----- -- S Marka -- Columbia University ----- ----- -- Astrophysical Messengers (Neutrinos, Gamma-Rays, Cosmic Rays) ----- -- R M Wagner -- Max-Planck-Institut für Physik ----- -- M Kachelriess -- University of Trondheim ----- -- M Kowalski -- University of Bonn ----- ----- -- Organizing Committee ----- -- N Fornengo -- Torino University and INFN ----- -- B Majorovits -- Max-Planck-Institut für Physik ----- -- L Oberauer -- Technische Universität M ü nchen (co-chair) ----- -- G Raffelt -- Max-Planck-Institut für Physik (co-chair) ----- -- S Rodríguez -- Max-Planck-Institut für Physik (conference secretary) ----- -- S Schönert -- Technische Universität München ----- -- D Sinclair -- SNO Laboratory & Carleton University ----- -- R M Wagner -- Max-Planck-Institut für Physik (scientific secretary) ----- -- B Wankerl -- Excellence Cluster 'Origin and Structure of the Universe' ----- -- M Wurm -- Technische Universität München ----- -- S Zollinger -- Max-Planck-Institut für Physik ----- ##IMG## [http://ej.iop.org/images/1742-6596/375/00/001001/group.jpg] {Conference photographPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98633/1/1742-6596_375_00_001001.pd

The HLMA project: determination of high delta-m^2 LMA mixing parameters and constraint on |U_e3| with a new reactor neutrino experiment

In the forthcoming months, the KamLAND experiment will probe the parameter space of the solar large mixing angle (LMA) MSW solution as the origin of the solar neutrino deficit with \nuebar's from distant nuclear reactors. If however the solution realized in nature is such that \Dm2_{sol} \gsim 2 \cdot 10^{-4} eV$^2$ (thereafter named the HLMA region), KamLAND will only observe a rate suppression but no spectral distortion and hence it will not have the optimal sensitivity to measure the mixing parameters. In this case, we propose a new medium baseline reactor experiment located at Heilbronn (Germany) to pin down the precise value of the solar mixing parameters. In this paper, we present the Heilbronn detector site, we calculate the \nuebar interaction rate and the positron spectrum expected from the surrounding nuclear power plants. We also discuss the sensitivity of such an experiment to |U_e3| in both normal and inverted neutrino mass hierarchy scenarios. We then outline the detector design, estimate background signals induced by natural radioactivity as well as by in-situ cosmic ray muon interaction, and discuss a strategy to detect the anti-neutrino signal 'free of background'.Comment: 22 pages, 5 figures; v2: added references, caption of Fig.4 and typos corrected; v3: accepted for publication in Astroparticle Physics, references added, typo in Sec. 6.3 correcte

Fast neutron production at the LNL Tandem from the 7^7Li(14^{14}N,xn)X reaction

Fast neutron beams are of relevance for many scientific and industrial applications. This paper explores fast neutron production using a TANDEM accelerator at the Legnaro National Laboratories, via an energetic ion beam (90 MeV $^{14}N$) onto a lithium target. The high energy models for nuclear collision of FLUKA foresee large neutron yields for reactions of this kind. The experiment aimed at validating the expected neutron yields from FLUKA simulations, using two separate and independent set-ups: one based on the multi-foil activation technique, and the other on the time of flight technique, by using liquid scintillator detectors. The results of the experiment show clear agreement of the measured spectra with the FLUKA simulations, both in the shape and the magnitude of the neutron flux at the measured positions. The neutron spectrum is centered around the 8 MeV range with mild tails, and a maximum neutron energy spanning up to 50 MeV. These advantageous results provide a starting point in the development of fast neutron beams based on high energy ion beams from medium-sized accelerator facilities

Development of a bi-solvent liquid scintillator with slow light emission

One of the most promising approaches for the next generation of neutrino experiments is the realization of large hybrid Cherenkov/scintillation detectors made possible by recent innovations in photodetection technology and liquid scintillator chemistry. The development of a potentially suitable future detector liquid with particularly slow light emission is discussed in the present publication. This cocktail is compared with respect to its fundamental characteristics (scintillation efficiency, transparency, and time profile of light emission) with liquid scintillators currently used in large-scale neutrino detectors. In addition, the optimization of the admixture of wavelength shifters for a scintillator with particularly high light emission is presented. Furthermore, the pulse-shape discrimination capabilities of the novel medium was studied using a pulsed particle accelerator driven neutron source. Beyond that, purification methods based on column chromatography and fractional vacuum distillation for the co-solvent DIN (Diisopropylnaphthalene) are discussed

Development of a Bi-solvent Liquid Scintillator with Slow Light Emission

One of the most promising approaches for the next generation of neutrino experiments is the realization of large hybrid Cherenkov/scintillation detectors made possible by recent innovations in photodetection technology and liquid scintillator chemistry. The development of a potentially suitable future detector liquid with particularly slow light emission is discussed in the present publication. This cocktail is compared with respect to its fundamental characteristics (scintillation efficiency, transparency, and time profile of light emission) with liquid scintillators currently used in large-scale neutrino detectors. In addition, the optimization of the admixture of wavelength shifters for a scintillator with particularly high light emission is presented. Furthermore, the pulse-shape discrimination capabilities of the novel medium was studied using a pulsed particle accelerator driven neutron source. Beyond that, purification methods based on column chromatography and fractional vacuum distillation for the co-solvent DIN (Diisopropylnaphthalene) are discussed