A £3 million X-ray camera that can take images at a speed equivalent to 4.5 million frames per second is being developed.
XFEL will use superconducting accelerator technology to accelerate electrons which then generate coherent X-ray flashes lasting less than 100fs with a peak brilliance a billion times higher than those produced by conventional X-ray sources.
With the properties of laser light, these short, intense flashes at wavelengths of 0.1-6nm will, for example, make it possible to capture three-dimensional images of single molecules.
Current leading-edge X-ray cameras are designed to capture images when matter is bombarded by a constant beam of X-rays.
STFC’s Large Pixel Detector (LPD), which is being co-developed with researchers at the University of Glasgow, is specifically designed for use with hyper-short, hyper-brilliant X-ray flashes.
European XFEL scientists believe that the images it will produce should provide new insights into the structure of matter, and lead to advances in fields such as drug discovery, when the facility begins operation in four years’ time.
Building the camera presents a range of technological challenges, reports Dr Tim Nicholls of STFC: “These include making the camera signal processing fast enough to cope with the high repetition rate of the XFEL X-ray pulses while also having the sensitivity to capture a huge dynamic range in signal – where the pixels have to be sensitive to just a few X-rays, all the way up to hundreds of thousands of X-rays per pixel.
“We’ve achieved this through an innovative ASIC design which collects and stores signals with three gain ranges simultaneously.”
“The camera is also mechanically and thermally challenging, as the power dissipation of the ASICs is high,” Nicholls explains.
“We have designed an innovative water-cooled heat exchanger that can remove all the heat but is light enough to let the camera be moved around easily.”