Filtern
Dokumenttyp
Sprache
- Englisch (2)
Referierte Publikation
- ja (2)
Schlagworte
- Polymers (2) (entfernen)
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.
A time domain spectrometer in the range of 0.5–2 THz was used for time of flight (ToF) measurements of THz pulses for imperfection detection in non metallic materials. The measurements were performed in comparison to the established ultra sound pulse echo (PE) and time of flight diffraction (ToFD) technique. No coupling agent and no contact to the surface is required for THz ToFD measurements. Plastic test specimen with notches, voids and drilled side holes were used to study reflected and diffracted response signals. No major differences were observed between the UT and THz ToFD records for the first surface of the notches, voids and holes. Additionally to the UT records also signals were obtained from its back side and a second raw of holes. The THz measurement is fast and has the potential to substitute UT applications in some industrial areas. Within the German project 'Handheld' the potential for miniaturization of the time domain equipment is explored for efficient application.