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Your search keyword '"Dreischuh, Tanja N."' showing total 145 results
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145 results on '"Dreischuh, Tanja N."'

1. Gamma-Ray backscattering tomography approach based on the lidar principle

Author

Gurdev, Ljuan L., Stoyanov, Dimitar V., Dreischuh, Tanja N., Protochristov, Christo N., and Vankov, Orlin I.

Subjects
Tomography -- Research, Compton effect -- Research, Electronic data processing -- Research, Gamma rays -- Research, Optical radar -- Research, Business, Electronics, Electronics and electrical industries
Abstract

An approach is proposed, and its potentialities are studied, for single-sided gamma-ray in-depth sensing and tomography of dense opaque media. The approach is based on lidar (LIgth Detection And Ranging) principle or, in the present case, graydar (Gamma RAY Detection And Ranging) principle, that is, time-to-range resolved detection of the backscattering-due radiative returns from the probed object irradiated by pulsed gamma-photon pencil beams. The basic analysis and data processing delta-pulse single-scattering graydar equation is formulated by analogy with the lidar equation and is shown to be applicable, under some determinate conditions, to the problems of gamma-ray in-depth profiling of dense media. It is shown analytically and by computer simulations that the approach developed in the work would enable one, at large-enough but reasonable sensing photon fluxes and measurement time intervals, to determine with good controllable accuracy and resolution the location, the material content, and the mass density of different homogeneous ingredients inside the probed object as well as the mass (or electron) density distribution within one-material objects. This approach can be widely applied, e.g., for nondestructive material examination in industry and aviation, detection of landmines and explosives, investigating the constitution of archeological artifacts, etc. Index Terms--Compton scattering, gamma-ray, lidar, nondestructive evaluation, tomography.

Published
2007

2. High-range-resolution velocity-estimation techniques for coherent Doppler lidars with exponentially shaped laser pulses

Author

Gurdev, Ljuan L., Dreischuh, Tanja N., and Stoyanov, Dimitar V.

Subjects
Optics -- Usage, Doppler effect -- Usage, Lasers -- Research, Optical radar -- Methods, Astronomy, Physics
Abstract

On the basis of an analysis of the autocovariance of the complex heterodyne signal, some novel algorithms are derived and investigated for recovering the nonuniform Doppler-velocity coherent-lidar profiles within the lidar resolution interval conditioned by the sensing laser-pulse length. The case of exponentially shaped sensing laser pulses is considered. The algorithm performance and efficiency are studied and illustrated by computer simulations (based on the use of pulse models and real laser pulses), taking into account the influence of additive noise and radial-velocity fluctuations. It is shown that, at some reasonable number of signal realizations used and with appropriate data processing to suppress the noise effects, the Doppler-velocity profiles can be determined with a considerably shorter resolution interval in comparison with that (usually accepted as a lower bound) determined by the pulse length. OCIS codes: 280.0280, 280.3640.

Published
2002

11. Model Forecasts Importance in LIDAR-Data Analysis.

Author

Deleva, Atanaska D., Krasteva, Elena N., Vulkova, Liliya A., and Dreischuh, Tanja N.

Subjects
ATMOSPHERIC aerosols, LIDAR, DATA analysis, HYDROLOGIC cycle, AIR quality
Abstract

Aerosols play a major role in atmospheric processes concerning the Еarth’s radiation budget, clouds formation, atmospheric chemistry and physics, hydrological cycle and biosphere, ecosystems, air quality and public health. Elastic-backscatter lidars are widely used to measure the vertical distribution of the atmospheric aerosol layers and to retrieve the vertical profiles of the aerosols’ optical properties. This paper is focused on the importance of the information obtained from various forecasting models in determining the origin of aerosol layers in the atmosphere, as detected by a lidar. We analyze the results of three measurements during which relatively stable thin aerosol layers, similar in their position and geometrical parameters, were registered in the free troposphere. However, on the basis of additional information from the forecast models, distinctly different conclusions can be drawn about their origin. For two of the reported analyses, it is inferred that the aerosols layers contained mainly Saharan dust, while for the third one, that a long-range transported smoke from huge fires in Canada was registered. [ABSTRACT FROM AUTHOR]

Published
2019
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12. Thick Anthropogenic Aerosol Layers Detected by LIDAR above Sofia.

Author

Deleva, Atanaska D., Krasteva, Elena N., Vulkova, Liliya A., and Dreischuh, Tanja N.

Subjects
ANTHROPOGENIC effects on nature, ATMOSPHERIC aerosols, LIDAR, WAVELENGTHS
Abstract

In this work we present selected experimental results from lidar studies of the troposphere performed above Sofia, Bulgaria, during the summer of 2011. The ground-based measurements were carried out by a lidar equipped with a Nd:YAG laser operating at the wavelengths of 532 nm and 1064 nm. The lidar data are presented and analyzed in terms of calculated vertical atmospheric backscatter coefficient profiles and 2D color maps of the range-corrected lidar signals. They reveal that relatively thick (till 3.5-5 km) aerosol formations were observed over the urban areas. We used HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) backward trajectories and DREAM (Dust REgional Atmospheric Model) forecasts to analyze lidar profiles outlines and to characterize the phenomena observed. Analyzing the weather conditions we were able to explain the stable persistence of aerosols above the atmospheric boundary layer. As neither other aerosol sources (like fires, volcano eruption), nor dust transport from Sahara desert over the Balkans were forecast for the days of the measurements, our conclusion was that the relatively thick layers observed had been caused by anthropogenic aerosols produced from human activities and city’s traffic. [ABSTRACT FROM AUTHOR]

Published
2019
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44. Dark matter search by laser spectroscopy

Author

Dreischuh, Tanja N., Avramov, Latchezar A., Carugno, G., Braggio, C., Chiossi, F., Guarise, M., Dainelli, A., Calabrese, R., Khanbekyan, A., Luppi, E., Tomassetti, L., Marinelli, C., and Mariotti, E.

Published
2019
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