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Search Results: 1 - 10 of 328493 matches for " S. Sch?nert "
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LArGe: Background suppression using liquid argon (LAr) scintillation for 0$νββ$ decay search with enriched germanium (Ge) detectors
M. Di Marco,P. Peiffer,S. Schnert
Physics , 2006, DOI: 10.1016/j.nuclphysbps.2007.07.019
Abstract: Measurements with a bare p-type high purity germanium diode (HPGe) submerged in a 19 kg liquid argon (LAr) scintillation detector at MPIK Heidelberg are reported. The liquid argon--germanium system (LArGe) is operated as a 4$\pi$ anti-Compton spectrometer to suppress backgrounds in the HPGe. This R&D is carried out in the framework of the GERDA experiment which searches for 0$\nu\beta\beta$ decays with HPGe detectors enriched in $^{76}$Ge. The goal of this work is to develop a novel method to discriminate backgrounds in 0$\nu\beta\beta$ search which would ultimately allow to investigate the effective neutrino mass free of background events down to the inverse mass hierarchy scale. Other applications in low-background counting are expected.
Automatic Generation of Water Masks from RapidEye Images  [PDF]
Gideon Okpoti Tetteh, Maurice Schnert
Journal of Geoscience and Environment Protection (GEP) , 2015, DOI: 10.4236/gep.2015.310003

Water is a very important natural resource and it supports all life forms on earth. It is used by humans in various ways including drinking, agriculture and for scientific research. The aim of this research was to develop a routine to automatically extract water masks from RapidEye images, which could be used for further investigation such as water quality monitoring and change detection. A Python-based algorithm was therefore developed for this particular purpose. The developed routine combines three spectral indices namely Simple Ratios (SRs), Normalized Green Index (NGI) and Normalized Difference Water Index (NDWI). The two SRs are calculated between the NIR and green band, and between the NIR and red band. The NGI is calculated by rationing the green band to the sum of all bands in each image. The NDWI is calculated by differencing the green to the NIR and dividing by the sum of the green and NIR bands. The routine generates five intermediate water masks, which are spatially intersected to create a single intermediate water mask. In order to remove very small waterbodies and any remaining gaps in the intermediate water mask, morphological opening and closing were performed to generate the final water mask. This proposed algorithm was used to extract water masks from some RapidEye images. It yielded an Overall Accuracy of 95% and a mean Kappa Statistic of 0.889 using the confusion matrix approach.

Microscopic Model for the Scintillation-Light Generation and Light-Quenching in CaWO$_4$ single crystals
S. Roth,F. v. Feilitzsch,J. -C. Lanfranchi,W. Potzel,S. Schnert,A. Ulrich
Physics , 2015,
Abstract: Scintillators are employed for particle detection and identification using light-pulse shapes and light quenching factors. We developed a comprehensive model describing the light generation and quenching in CaWO$_4$ single crystals used for direct dark matter search. All observed particle-dependent light-emission characteristics can be explained quantitatively, light-quenching factors and light-pulse shapes are calculated on a microscopic basis. This model can be extended to other scintillators such as inorganic crystal scintillators, liquid noble gases or organic liquid scintillators.
PMT Test Facility at MPIK Heidelberg and Double Chooz Super Vertical Slice
J. Haser,F. Kaether,C. Langbrandtner,M. Lindner,B. Reinhold,S. Schnert
Physics , 2012, DOI: 10.1016/j.nuclphysbps.2012.09.093
Abstract: Proceedings supplement for conference poster at Neutrino 2010, Athens, Greece.
Attenuation of vacuum ultraviolet light in pure and xenon-doped liquid argon - an approach to an assignment of the near-infrared emission from the mixture
A. Neumeier,T. Dandl,A. Himpsl,L. Oberauer,W. Potzel,S. Schnert,A. Ulrich
Physics , 2015, DOI: 10.1209/0295-5075/111/12001
Abstract: Results of transmission experiments of vacuum ultraviolet light through a 11.6 cm long cell filled with pure and xenon-doped liquid argon are described. Pure liquid argon shows no attenuation down to the experimental short-wavelength cut-off at 118nm. Based on a conservative approach, a lower limit of 1.10 m for the attenuation length of its own scintillation light could be derived. Adding xenon to liquid argon at concentrations on the order of parts per million leads to strong xenon-related absorption features which are used for a tentative assignment of the recently found near-infrared emission observed in electron-beam excited liquid argon-xenon mixtures. Two of the three absorption features can be explained by perturbed xenon transitions and the third one by a trapped exciton (Wannier-Mott) impurity state. A calibration curve connecting the equivalent width of the absorption line at 140 nm with xenon concentration is provided.
Theorie der (literarischen) Satire. Ein funktionales Modell zur Beschreibung von Textstruktur und kommunikativer Wirkung
J?rg Schnert
Textpraxis : Digitales Journal für Philologie , 2011,
Abstract: Das entworfene Modell der literarischen Satire geht davon aus, dass satirische Kommunikation innerhalb der institutionalisierten Handlungen literarischer Kommunikation durch eine besondere Funktionalisierung von textuellem System und au ertextuellen Bezügen gekennzeichnet ist, die für die Textstruktur Relevanz hat. Der Beitrag verfolgt dabei auch ein theorie- und fachgeschichtliches Ziel und dokumentiert, wie in den sp ten 1960er und im Laufe der 1970er Jahre in der deutschsprachigen Literaturwissenschaft für den Gegenstandsbereich Theorie und Geschichte der Satire der Anschluss an die internationale Diskussion hergestellt wurde.
Large scale Gd-beta-diketonate based organic liquid scintillator production for antineutrino detection
C. Aberle,C. Buck,B. Gramlich,F. X. Hartmann,M. Lindner,S. Schnert,U. Schwan,S. Wagner,H. Watanabe
Physics , 2011, DOI: 10.1088/1748-0221/7/06/P06008
Abstract: Over the course of several decades, organic liquid scintillators have formed the basis for successful neutrino detectors. Gadolinium-loaded liquid scintillators provide efficient background suppression for electron antineutrino detection at nuclear reactor plants. In the Double Chooz reactor antineutrino experiment, a newly developed beta-diketonate gadolinium-loaded scintillator is utilized for the first time. Its large scale production and characterization are described. A new, light yield matched metal-free companion scintillator is presented. Both organic liquids comprise the target and "Gamma Catcher" of the Double Chooz detectors.
Attenuation measurements of vacuum ultraviolet light in liquid argon revisited
A. Neumeier,T. Dandl,A. Himpsl,M. Hofmann,L. Oberauer,W. Potzel,S. Schnert,A. Ulrich
Physics , 2015, DOI: 10.1016/j.nima.2015.07.051
Abstract: The attenuation of vacuum ultraviolet light in liquid argon in the context of its application in large liquid noble gas detectors has been studied. Compared to a previous publication several technical issues concerning transmission measurements in general are addressed and several systematic effects were quantitatively measured. Wavelength-resolved transmission measurements have been performed from the vacuum ultraviolet to the near-infrared region. On the current level of sensitivity with a length of the optical path of 11.6 cm, no xenon-related absorption effects could be observed, and pure liquid argon is fully transparent down to the short wavelength cut-off of the experimental setup at 118 nm. A lower limit for the attenuation length of pure liquid argon for its own scintillation light has been estimated to be 1.10 m based on a very conservative approach.
Attenuation of vacuum ultraviolet light in liquid argon
A. Neumeier,M. Hofmann,L. Oberauer,W. Potzel,S. Schnert,T. Dandl,T. Heindl,A. Ulrich,J. Wieser
Physics , 2015, DOI: 10.1140/epjc/s10052-012-2190-z
Abstract: The transmission of liquid argon has been measured, wavelength resolved, for a wavelength interval from 118 to 250 nm. The wavelength dependent attenuation length is presented for pure argon. It is shown that no universal wavelength independent attenuation length can be assigned to liquid argon for its own fluorescence light due to the interplay between the wavelength dependent emission and absorption. A decreasing transmission is observed below 130 nm in both chemically cleaned and distilled liquid argon and assigned to absorption by the analogue of the first argon excimer continuum. For not perfectly cleaned argon a strong influence of impurities on the transmission is observed. Two strong absorption bands at 126.5 and 141.0 nm with approximately 2 and 4 nm width, respectively, are assigned to traces of xenon in argon. A broad absorption region below 180 nm is found for unpurified argon and tentatively attributed to the presence of water in the argon sample.
Ion-beam excitation of liquid argon
M. Hofmann,T. Dandl,T. Heindl,A. Neumeier,L. Oberauer,W. Potzel,S. Roth,S. Schnert,J. Wieser,A. Ulrich
Physics , 2015, DOI: 10.1140/epjc/s10052-013-2618-0
Abstract: The scintillation light of liquid argon has been recorded wavelength and time resolved with very good statistics in a wavelength interval ranging from 118 nm through 970 nm. Three different ion beams, protons, sulfur ions and gold ions, were used to excite liquid argon. Only minor differences were observed in the wavelength-spectra obtained with the different incident particles. Light emission in the wavelength range of the third excimer continuum was found to be strongly suppressed in the liquid phase. In time-resolved measurements, the time structure of the scintillation light can be directly attributed to wavelength in our studies, as no wavelength shifter has been used. These measurements confirm that the singlet-to-triplet intensity ratio in the second excimer continuum range is a useful parameter for particle discrimination, which can also be employed in wavelength-integrated measurements as long as the sensitivity of the detector system does not rise steeply for wavelengths longer than 190 nm. Using our values for the singlet-to-triplet ratio down to low energies deposited a discrimination threshold between incident protons and sulfur ions as low as $\sim$2.5 keV seems possible, which represents the principle limit for the discrimination of these two species in liquid argon.
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