TY - CONF A1 - Beckmann, Jörg A1 - Fratzscher, Daniel A1 - von Chrzanowski, Lars A1 - Ewert, Uwe T1 - Zeitaufgelöste THz-Spektroskopie für technische und zivile Sicherheitsanwendungen T2 - DACH-Jahrestagung 2012 - ZfP in Forschung, Entwicklung und Anwendung (Proceedings) N2 - Vortrag über Zeitaufgelöste THz-Spektroskopie für technische und zivile Sicherheitsanwendungen T2 - DACH-Jahrestagung 2012 CY - Graz, Austria DA - 17.09.2012 KW - THz Spektroskopie KW - Technische und zivile Sicherheit PY - 2012 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-280013 SN - 978-3-940283-44-3 IS - DGZfP-BB 136 SP - Mi.1.C.4, 1 EP - 14 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung e.V. (DGZfP) AN - OPUS4-28001 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fratzscher, Daniel A1 - Beckmann, Jörg A1 - von Chrzanowski, Lars A1 - Ewert, Uwe T1 - Computed THz - tomography T2 - 18th WCNDT - World conference on nondestructive testing (Proceedings) N2 - Available THz Time Domain Spectroscopy (THz-TDS) systems can be applied in a pulse echo mode for tomographic application. In contrast to common transmission methods, a TDS reflection geometry was used to inspect cylindrical polyethylene samples with internal voids of known shape. The geometry of the voids was simulated and its shape was reconstructed. B-scan pulse echo images were acquired in the time domain, similar to UT pulse echo techniques on basis of the numeric model. The results were used to verify the simulation model and the reconstruction algorithm, based on a modified Synthetic Aperture Focusing Technique (SAFT). The model was used to conclude recommendations on an optimized measurement setup in the reflection mode. Based on that, the quality of the reconstructed tomograms was improved. T2 - 18th WCNDT - World conference on nondestructive testing CY - Durban, South Africa DA - 2012-04-16 KW - THz KW - Computed tomography KW - Non metallics KW - SAFT KW - Delaminations PY - 2012 SN - 978-0-620-52872-6 SP - 1 EP - 10 (Paper 291) AN - OPUS4-25874 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beckmann, Jörg A1 - von Chrzanowski, Lars A1 - Fratzscher, Daniel A1 - Ewert, Uwe ED - Thompson, D. O. ED - Chimenti, D. E. T1 - Spectral and spatial nondestructive examination of dielectric materials with THz time domain spectroscopy T2 - Review of progress in quantitative nondestructive evaluation, volume 31 N2 - A time domain spectrometer T-ray 2000® operating in the range of 0.2-2 THz was used for Time of Flight measurements. A series of ethanol water mixtures from 10% to 90% were produced subsequently filled in polystyrene cells and analyzed in the T-ray 2000 TDS system in the reflection mode. The reflectivity of the material liquid interface is strongly influenced by the ethanol concentration in water. The reciprocal reflection coefficient of the material liquid interface was found to be a useful discriminating feature for further Probably of Detection calculations which can be used for the performance evaluation of potential THz bottle scanners. THz pulse echo (PE) measurements were performed in comparison to the established ultra sound PE technique for flaw detection of plastics. Synthetic aperture reconstructions were applied for simulated data to reconstruct the flaw shape. The results were compared with B-scan images of a high density polyethylene (HDPE) test cylinder. Existing restrictions on the quality of the back projected images and limits of the existing model are discussed in detail. T2 - 38th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Burlington, VT, USA DA - 17.07.2011 KW - Terahertz time domain spectroscopy KW - Time of flight diffraction KW - Non destructive testing KW - Polymers KW - Probability of detection KW - Thz Tomography PY - 2012 SN - 978-0-7354-1013-8 DO - https://doi.org/10.1063/1.4716279 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings VL - 31A IS - 1430 SP - 573 EP - 580 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-26103 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -