Scientists from the European Synchrotron Radiation Facility (France) the Forschungszentrum Karlsruhe, the Technische Universität Berlin and the Helmholtz Zentrum Berlin (all Germany) were able to make fast processes inside opaque objects visible, by using white synchrotron radiation to perform hard X-ray radioscopy with high spatio-temporal resolution. The required imaging detector was constructed out of a standard indirect detector in combination with a Photron SA1 CMOS-based camera. Thus, it was possible to investigate pore coalescence and individual cell wall collapse in an expanding liquid metal foam: the rupture of a film and the subsequent merger of two neighbouring bubbles could be recorded with a time sampling rate of 40000 frames per second (25 micorseconds exposure time). The results as published in the Journal of Synchrotron Radiation (http://journals.iucr.org/s/issues/2009/03/00/kv5057/ – open access) allowed to determine that the pore stability in a liquid metal foam is driven by intertia and not the viscosity of the melt. This knowledge is crucial in order to adapt metal foaming process for industrial production.
Together with his research team, Professor Vasilis Ntziachristos from the Helmholtz Zentrum Munich, Germany and the Technical University Munich, Germany developed a new technology to make light audible. The technique, called multi-spectral opto-acoustic tomography (MSOT), combines light and ultrasound to visualize fluorescent proteins that are seated several centimeters deep into living tissue.
The researchers used a genetically modified adult zebra fish which carried fluorescent pigments in its tissue. They illuminated the fish from multiple angles using flashes of laser light that are absorbed by the fluorescent pigments in the fish. The pigments absorb the light, a process that causes slight local increases of temperature, which in turn result in tiny local volume expansions. This happens very quickly and creates small shock waves. In effect, the short laser pulse gives rise to an ultrasound wave that the researchers pick up with an ultrasound microphone. To analyze the resulting acoustic patterns, a computer is attached. The computer uses specially developed mathematical formulas to evaluate and interpret the specific distortions caused by scales, muscles, bones and internal organs to generate a three-dimensional image. In the future this technology may facilitate the examination of tumors or coronary vessels in humans.