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Search Results: 1 - 10 of 117846 matches for " T. Lewke "
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Results from the Borexino Experiment
Timo Lewke
Physics , 2009,
Abstract: Borexino is a low threshold liquid-scintillator detector for solar neutrinos located in the LNGS underground laboratory, Italy. Because of the ultra-high radio purity it is the first experiment able to do a real time analysis of the low energetic solar neutrinos. A detection of the solar 7Be neutrinos with a rate of 47+-7 counts/day/100tons can be reported (192 days of live time measurement). 8B neutrinos are observed with a rate of 0.26+-0.06 counts/day/100tons after 246 live days. All detected neutrino fluxes agree with the SSM predictions in case of the MSW-LMA oscillation solution. Borexino is the first experiment with the ablility to simultaneously measure solar neutrino oscillation in the vacuum-dominated and the matter-enhanced energy regions.
Electromagnetic Interference on Large Wind Turbines
Florian Krug,Bastian Lewke
Energies , 2009, DOI: 10.3390/en20401118
Abstract: Electromagnetic interference (EMI) can both affect and be transmitted by mega-watt wind turbines. This paper provides a general overview on EMI with respect to mega-watt wind turbines. Possibilities of measuring all types of electromagnetic interference are shown. Electromagnetic fields resulting from a GSM transmitter mounted on a mega-watt wind turbine will be analyzed in detail. This cellular system operates as a real-time communication link. The method-of-moments is used to analytically describe the electro-magnetic fields. The electromagnetic interference will be analyzed under the given boundary condition with a commercial simulation tool. Different transmitter positions are judged on the basis of their radiation patterns. The principal EMI mechanisms are described and taken into consideration.
The Physics Potential of the LENA Detector
Michael Wurm,Franz von Feilitzsch,Marianne Goeger-Neff,Tobias Lachenmaier,Timo Lewke,Quirin Meindl,Randolph Moellenberg,Lothar Oberauer,Juha Peltoniemi,Walter Potzel,Marc Tippmann,Juergen Winter
Physics , 2010,
Abstract: The large-volume liquid-scintillator detector LENA (Low Energy Neutrino Astronomy) has been proposed as a next-generation experiment for low-energy neutrinos. High-precision spectroscopy of solar, Supernova and geo-neutrinos provides a new access to the otherwise unobservable interiors of Earth, Sun and heavy stars. Due to the potent background discrimination, the detection of the Diffuse Supernova Neutrino Background is expected for the first time in LENA. The sensitivity of the proton lifetime for the decay into Kaon and antineutrino will be increased by an order of magnitude over existing experimental limits. Recent studies indicate that liquid-scintillator detectors are capable to reconstruct neutrino events even at GeV energies, providing the opportunity to use LENA as far detector in a long-baseline neutrino beam experiment.
Optical Scattering Lengths in Large Liquid-Scintillator Neutrino Detectors
Michael Wurm,Franz von Feilitzsch,Marianne Goeger-Neff,Martin Hofmann,Tobias Lachenmaier,Timo Lewke,Teresa Marrodan Undagoitita,Quirin Meindl,Randoplh Moellenberg,Lothar Oberauer,Walter Potzel,Marc Tippmann,Sebastian Todor,Christoph Traunsteiner,Juergen Winter
Physics , 2010, DOI: 10.1063/1.3397322
Abstract: For liquid-scintillator neutrino detectors of kiloton scale, the transparency of the organic solvent is of central importance. The present paper reports on laboratory measurements of the optical scattering lengths of the organic solvents PXE, LAB, and Dodecane which are under discussion for next-generation experiments like SNO+, Hanohano, or LENA. Results comprise the wavelength range from 415 to 440nm. The contributions from Rayleigh and Mie scattering as well as from absorption/re-emission processes are discussed. Based on the present results, LAB seems to be the preferred solvent for a large-volume detector.
The LAGUNA design study- towards giant liquid based underground detectors for neutrino physics and astrophysics and proton decay searches
LAGUNA Collaboration,D. Angus,A. Ariga,D. Autiero,A. Apostu,A. Badertscher,T. Bennet,G. Bertola,P. F. Bertola,O. Besida,A. Bettini,C. Booth,J. L. Borne,I. Brancus,W. Bujakowsky,J. E. Campagne,G. Cata Danil,F. Chipesiu,M. Chorowski,J. Cripps,A. Curioni,S. Davidson,Y. Declais,U. Drost,O. Duliu,J. Dumarchez,T. Enqvist,A. Ereditato,F. von Feilitzsch,H. Fynbo,T. Gamble,G. Galvanin,A. Gendotti,W. Gizicki,M. Goger-Neff,U. Grasslin,D. Gurney,M. Hakala,S. Hannestad,M. Haworth,S. Horikawa,A. Jipa,F. Juget,T. Kalliokoski,S. Katsanevas,M. Keen,J. Kisiel,I. Kreslo,V. Kudryastev,P. Kuusiniemi,L. Labarga,T. Lachenmaier,J. C. Lanfranchi,I. Lazanu,T. Lewke,K. Loo,P. Lightfoot,M. Lindner,A. Longhin,J. Maalampi,M. Marafini,A. Marchionni,R. M. Margineanu,A. Markiewicz,T. Marrodan-Undagoita,J. E. Marteau,R. Matikainen,Q. Meindl,M. Messina,J. W. Mietelski,B. Mitrica,A. Mordasini,L. Mosca,U. Moser,G. Nuijten,L. Oberauer,A. Oprina,S. Paling,S. Pascoli,T. Patzak,M. Pectu,Z. Pilecki,F. Piquemal,W. Potzel,W. Pytel,M. Raczynski,G. Rafflet,G. Ristaino,M. Robinson,R. Rogers,J. Roinisto,M. Romana,E. Rondio,B. Rossi,A. Rubbia,Z. Sadecki,C. Saenz,A. Saftoiu,J. Salmelainen,O. Sima,J. Slizowski,K. Slizowski,J. Sobczyk,N. Spooner,S. Stoica,J. Suhonen,R. Sulej,M. Szarska,T. Szeglowski,M. Temussi,J. Thompson,L. Thompson,W. H. Trzaska,M. Tippmann,A. Tonazzo,K. Urbanczyk,G. Vasseur,A. Williams,J. Winter,K. Wojutszewska,M. Wurm,A. Zalewska,M. Zampaolo,M. Zito
Physics , 2009,
Abstract: The feasibility of a next generation neutrino observatory in Europe is being considered within the LAGUNA design study. To accommodate giant neutrino detectors and shield them from cosmic rays, a new very large underground infrastructure is required. Seven potential candidate sites in different parts of Europe and at several distances from CERN are being studied: Boulby (UK), Canfranc (Spain), Fr\'ejus (France/Italy), Pyh\"asalmi (Finland), Polkowice-Sieroszowice (Poland), Slanic (Romania) and Umbria (Italy). The design study aims at the comprehensive and coordinated technical assessment of each site, at a coherent cost estimation, and at a prioritization of the sites within the summer 2010.
Solar neutrino physics with Borexino I
L. Ludhova,G. Bellini,J. Benziger,D. Bick,G. Bonfini,D. Bravo,M. Buizza Avanzini,B. Caccianiga,L. Cadonati,F. Calaprice,C. Carraro,P. Cavalcante,A. Chavarria,D. D'Angelo,S. Davini,A. Derbin,A. Etenko,K. Fomenko,D. Franco,C. Galbiati,S. Gazzana,C. Ghiano,M. Giammarchi,M. Goeger-Nef,A. Goretti,L. Grandi,E. Guardincerri,S. Hardy,Aldo Ianni,Andrea Ianni,A. Kayunov,V. Kobychev,D. Korablev,G. Korga,Y. Koshio,D. Kryn,M. Laubenstein,T. Lewke,E. Litvinovich,B. Loer,F. Lombardi,P. Lombardi,I. Machulin,S. Manecki,W. Maneschg,G. Manuzio,Q. Meindl,E. Meroni,L. Miramonti,M. Misiaszek,D. Montanari,P. Mosteiro,V. Muratova,L. Oberauer,M. Obolenksy,F. Ortica,K. Otis,M. Pallavicini,L. Papp,L. Perasso,S. Perasso,A. Pocar,R. S. Raghavan,G. Ranucci,A. Razeto,A. Re,P. A. Romani,A. Sabelnikov,R. Saldanha,C. Salvo,S. Schoenert,H. Simgen,M. Skorokhvatov,O. Smirnov,A. Sotnikov,S. Sukhotin,Y. Suvorov,R. Tartaglia,G. Testera,D. Vignaud,R. B. Vogelaar,F. Von Feilitzsch,J. Winter,M. Wojcik,A. Wright,M. Wurm,J. Xu,O. Zaimidoroga,S. Zavatarelli,G. Zuzel
Physics , 2012,
Abstract: Borexino is a large-volume liquid scintillator detector installed in the underground halls of the Laboratori Nazionali del Gran Sasso in Italy. After several years of construction, data taking started in May 2007. The Borexino phase I ended after about three years of data taking. Borexino provided the first real time measurement of the $^{7}$Be solar neutrino interaction rate with accuracy better than 5% and confirmed the absence of its day-night asymmetry with 1.4% precision. This latter Borexino results alone rejects the LOW region of solar neutrino oscillation parameters at more than 8.5 $\sigma$ C.L. Combined with the other solar neutrino data, Borexino measurements isolate the MSW-LMA solution of neutrino oscillations without assuming CPT invariance in the neutrino sector. Borexino has also directly observed solar neutrinos in the 1.0-1.5 MeV energy range, leading to the first direct evidence of the $pep$ solar neutrino signal and the strongest constraint of the CNO solar neutrino flux up to date. Borexino provided the measurement of the solar $^{8}$B neutrino rate with 3 MeV energy threshold.
Solar neutrino with Borexino: results and perspectives
O. Smirnov,G. Bellini,J. Benziger,D. Bick,G. Bonfini,D. Bravo,B. Caccianiga,F. Calaprice,A. Caminata,P. Cavalcante,A. Chavarria,A. Chepurnov,D. D'Angelo,S. Davini,A. Derbin,A. Empl,A. Etenko,K. Fomenko,D. Franco,G. Fiorentini,C. Galbiati,S. Gazzana,C. Ghiano,M. Giammarchi,M. Goeger-Neff,A. Goretti,C. Hagner,E. Hungerford,Aldo Ianni,Andrea Ianni,V. Kobychev,D. Korablev,G. Korga,D. Kryn,M. Laubenstein,B. Lehnert,T. Lewke,E. Litvinovich,F. Lombardi,P. Lombardi,L. Ludhova,G. Lukyanchenko,I. Machulin,S. Manecki,W. Maneschg,F. Mantovani,S. Marcocci,Q. Meindl,E. Meroni,M. Meyer,L. Miramonti,M. Misiaszek,P. Mosteiro,V. Muratova,L. Oberauer,M. Obolensky,F. Ortica,K. Otis,M. Pallavicini,L. Papp,L. Perasso,A. Pocar,G. Ranucci,A. Razeto,A. Re,B. Ricci,A. Romani,N. Rossi,R. Saldanha,C. Salvo,S. Schoenert,H. Simgen,M. Skorokhvatov,A. Sotnikov,S. Sukhotin,Y. Suvorov,R. Tartaglia,G. Testera,D. Vignaud,R. B. Vogelaar,F. von Feilitzsch,H. Wang,J. Winter,M. Wojcik,A. Wright,M. Wurm,O. Zaimidoroga,S. Zavatarelli,K. Zuber,G. Zuzel
Physics , 2014, DOI: 10.1134/S1063779615020185
Abstract: Borexino is a unique detector able to perform measurement of solar neutrinos fluxes in the energy region around 1 MeV or below due to its low level of radioactive background. It was constructed at the LNGS underground laboratory with a goal of solar $^{7}$Be neutrino flux measurement with 5\% precision. The goal has been successfully achieved marking the end of the first stage of the experiment. A number of other important measurements of solar neutrino fluxes have been performed during the first stage. Recently the collaboration conducted successful liquid scintillator repurification campaign aiming to reduce main contaminants in the sub-MeV energy range. With the new levels of radiopurity Borexino can improve existing and challenge a number of new measurements including: improvement of the results on the Solar and terrestrial neutrino fluxes measurements; measurement of pp and CNO solar neutrino fluxes; search for non-standard interactions of neutrino; study of the neutrino oscillations on the short baseline with an artificial neutrino source (search for sterile neutrino) in context of SOX project.
Recent Borexino results and prospects for the near future
D. D'Angelo,G. Bellini,J. Benziger,D. Bick,G. Bonfini,M. Buizza Avanzini,B. Caccianiga,L. Cadonati,F. Calaprice,P. Cavalcante,A. Chavarria,A. Chepurnov,S. Davini,A. Derbin,A. Empl,A. Etenko,F. von Feilitzsch,K. Fomenko,D. Franco,C. Galbiati,S. Gazzana,C. Ghiano,M. Giammarchi,M. Goeger-Neff,A. Goretti,L. Grandi,C. Hagner,E. Hungerford,Aldo Ianni,Andrea Ianni,V. Kobychev,D. Korablev,G. Korga,D. Kryn,M. Laubenstein,B. Lehnert,T. Lewke,E. Litvinovich,F. Lombardi,P. Lombardi,L. Ludhova,G. Lukyanchenko,I. Machulin,S. Manecki,W. Maneschg,G. Manuzio,Q. Meindl,E. Meroni,L. Miramonti,M. Misiaszek,P. Mosteiro,V. Muratova,L. Oberauer,M. Obolensky,F. Ortica,K. Otis,M. Pallavicini,L. Papp,L. Perasso,S. Perasso,A. Pocar,G. Ranucci,A. Razeto,A. Re,A. Romani,N. Rossi,R. Saldanha,C. Salvo,S. Schoenert,H. Simgen,M. Skorokhvatov,O. Smirnov,A. Sotnikov,S. Sukhotin,Y. Suvorov,R. Tartaglia,G. Testera,D. Vignaud,R. B. Vogelaar,J. Winter,M. Wojcik,A. Wright,M. Wurm,J. Xu,O. Zaimidoroga,S. Zavatarelli,K. Zuber,G. Zuzel
Physics , 2014,
Abstract: The Borexino experiment, located in the Gran Sasso National Laboratory, is an organic liquid scintillator detector conceived for the real time spectroscopy of low energy solar neutrinos. The data taking campaign phase I (2007 - 2010) has allowed the first independent measurements of 7Be, 8B and pep fluxes as well as the first measurement of anti-neutrinos from the earth. After a purification of the scintillator, Borexino is now in phase II since 2011. We review here the recent results achieved during 2013, concerning the seasonal modulation in the 7Be signal, the study of cosmogenic backgrounds and the updated measurement of geo-neutrinos. We also review the upcoming measurements from phase II data (pp, pep, CNO) and the project SOX devoted to the study of sterile neutrinos via the use of a 51Cr neutrino source and a 144Ce-144Pr antineutrino source placed in close proximity of the active material.
Cosmic-muon flux and annual modulation in Borexino at 3800 m water-equivalent depth
G. Bellini,J. Benziger,D. Bick,G. Bonfini,D. Bravo,M. Buizza Avanzini,B. Caccianiga,L. Cadonati,F. Calaprice,C. Carraro,P. Cavalcante,A. Chavarria,A. Chepurnov,D. D'Angelo,S. Davini,A. Derbin,A. Etenko,F. von Feilitzsch,K. Fomenko,D. Franco,C. Galbiati,S. Gazzana,C. Ghiano,M. Giammarchi,M. Goeger-Neff,A. Goretti,L. Grandi,E. Guardincerri,C. Hagner,S. Hardy,Aldo Ianni,Andrea Ianni,D. Korablev,G. Korga,Y. Koshio,D. Kryn,M. Laubenstein,T. Lewke,E. Litvinovich,B. Loer,F. Lombardi,P. Lombardi,L. Ludhova,I. Machulin,S. Manecki,W. Maneschg,G. Manuzio,Q. Meindl,E. Meroni,L. Miramonti,M. Misiaszek,D. Montanari,P. Mosteiro,V. Muratova,L. Oberauer,M. Obolensky,F. Ortica,K. Otis,M. Pallavicini,L. Papp,L. Perasso,S. Perasso,A. Pocar,R. S. Raghavan,G. Ranucci,A. Razeto,A. Re,A. Romani,A. Sabelnikov,R. Saldanha,C. Salvo,S. Sch?nert,H. Simgen,M. Skorokhvatov,O. Smirnov,A. Sotnikov,S. Sukhotin,Y. Suvorov,R. Tartaglia,G. Testera,D. Vignaud,R. B. Vogelaar,J. Winter,M. Wojcik,A. Wright,M. Wurm,J. Xu,O. Zaimidoroga,S. Zavatarelli,G. Zuzel
Physics , 2012, DOI: 10.1088/1475-7516/2012/05/015
Abstract: We have measured the muon flux at the underground Gran Sasso National Laboratory (3800 m w.e.) to be (3.41 \pm 0.01) \times 10-4m-2s-1 using four years of Borexino data. A modulation of this signal is observed with a period of (366\pm3) days and a relative amplitude of (1.29 \pm 0.07)%. The measured phase is (179 \pm 6) days, corresponding to a maximum on the 28th of June. Using the most complete atmospheric data models available, muon rate fluctuations are shown to be positively correlated with atmospheric temperature, with an effective coefficient {\alpha}T = 0.93 \pm 0.04. This result represents the most precise study of the muon flux modulation for this site and is in good agreement with expectations.
Measurement of geo-neutrinos from 1353 days of Borexino
G. Bellini,J. Benziger,D. Bick,G. Bonfini,D. Bravo,M. Buizza Avanzini,B. Caccianiga,L. Cadonati,F. Calaprice,P. Cavalcante,A. Chavarria,A. Chepurnov,D. D'Angelo,S. Davini,A. Derbin,A. Empl,A. Etenko,G. Fiorentini,K. Fomenko,D. Franco,C. Galbiati,S. Gazzana,C. Ghiano,M. Giammarchi,M. Goeger-Neff,A. Goretti,L. Grandi,C. Hagner,E. Hungerford,Aldo Ianni,Andrea Ianni,V. V. Kobychev,D. Korablev,G. Korga,Y. Koshio,D. Kryn,M. Laubenstein,T. Lewke,E. Litvinovich,B. Loer,P. Lombardi,F. Lombardi,L. Ludhova,G. Lukyanchenko,I. Machulin,S. Manecki,W. Maneschg,F. Mantovani,G. Manuzio,Q. Meindl,E. Meroni,L. Miramonti,M. Misiaszek,P. Mosteiro,V. Muratova,L. Oberauer,M. Obolensky,F. Ortica,K. Otis,M. Pallavicini,L. Papp,L. Perasso,S. Perasso,A. Pocar,G. Ranucci,A. Razeto,A. Re,B. Ricci,A. Romani,N. Rossi,A. Sabelnikov,R. Saldanha,C. Salvo,S. Schoenert,H. Simgen,M. Skorokhvatov,O. Smirnov,A. Sotnikov,S. Sukhotin,Y. Suvorov,R. Tartaglia,G. Testera,D. Vignaud,R. B. Vogelaar,F. von Feilitzsch,J. Winter,M. Wojcik,A. Wright,M. Wurm,J. Xu,O. Zaimidoroga,S. Zavatarelli,G. Zuzel
Physics , 2013, DOI: 10.1016/j.physletb.2013.04.030
Abstract: We present a measurement of the geo--neutrino signal obtained from 1353 days of data with the Borexino detector at Laboratori Nazionali del Gran Sasso in Italy. With a fiducial exposure of (3.69 $\pm$ 0.16) $\times$ $10^{31}$ proton $\times$ year after all selection cuts and background subtraction, we detected (14.3 $\pm$ 4.4) geo-neutrino events assuming a fixed chondritic mass Th/U ratio of 3.9. This corresponds to a geo-neutrino signal $S_{geo}$ = (38.8 $\pm$ 12.0) TNU with just a 6 $\times$ $10^{-6}$ probability for a null geo-neutrino measurement. With U and Th left as free parameters in the fit, the relative signals are $S_{\mathrm{Th}}$ = (10.6 $\pm$ 12.7) TNU and $S_\mathrm{U}$ = (26.5 $\pm$ 19.5) TNU. Borexino data alone are compatible with a mantle geo--neutrino signal of (15.4 $\pm$ 12.3) TNU, while a combined analysis with the KamLAND data allows to extract a mantle signal of (14.1 $\pm$ 8.1) TNU. Our measurement of a reactor anti--neutrino signal $S_{react}$ = 84.5$^{+19.3}_{-18.9}$ TNU is in agreement with expectations in the presence of neutrino oscillations.
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