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.
Researchers at the UCLA (University of California, Los Angeles, US) Henry Samueli School of Engineering and Applied Sciences have developed the serial time-encoded amplified microscopy (STEAM) technology. It is a novel, continuously running camera that enables real-time imaging at a frame rate of more than 6 MHz and a shutter speed of less than 450ps – roughly a thousand times faster than any conventional camera. Keisuke Goda, Kevin Tsia and team leader Bahram Jalali describe a new approach that does not require a traditional CCD (charge-couples device) or CMOS (complementary metal-oxide semiconductor) video camera. The new imager operates by capturing each picture with an ultrashort laser pulse. It then converts each pulse to a serial data stream that resembles the data in a fiber optic network rather than the signal coming out of the camera. Using a technique known as amplified dispersive Fourier transform, these laser pulses, each containing an entire picture, are amplified and simultaneously stretched in time to the point that they are slow enough to be captured with an electronic digitizer. Those cameras could be used for observing high-speed events such as shockwaves, communication between cells, neural activity or laser surgery.