5 July 2017
An attosecond is to a second what a second is to 32 billion years. This is how fast the short pulses of light operated by a Free Electron Laser (FEL) particle accelerator could be operating at in the not too distant future, unlocking new windows of scientific exploration.
A brand new research facility that is currently under construction at the Science and Technology Facilities Council’s (STFC) Daresbury Laboratory in Cheshire is ready to become the world’s first facility designed to develop, test and advance new technologies for this next generation of FEL accelerator. CLARA (Compact Linear Accelerator for Research and Applications) has just successfully generated its first electrons, a significant milestone in its development, as it aims to bring the UK’s world leading expertise and experience of FELs to a whole new level.
A FEL is unparalleled in its capability as a light source and is poised to be responsible for significant scientific breakthroughs in areas ranging from healthcare and new materials to sustainable energy. Scientists have already demonstrated its capabilities in a number of areas, from developing materials for the aero industry, to understanding new ways of controlling mosquito-borne diseases, to name a couple. But FEL technology is still at a relatively early stage and the potential for improvements is enormous. With very few FEL research capabilities in existence, new ideas and developments are extremely difficult to model and test experimentally.
CLARA will provide the vital stepping stone between the development and testing of multiple new FEL technologies and their implementation onto any existing or planned FEL facility, in the UK or internationally.
Professor Jim Clarke, Head of Science Division at STFC’s Accelerator Science and Technology Centre at Daresbury, said: “The next generation of FEL light sources will be a game changer in science research, and it is vital that we have the skills and facilities in place to be able to develop and test new FEL technologies. The design and development of CLARA has been particularly complex, so the generation of first electrons is a particularly exciting milestone. The impact of this is huge and will ensure that the UK has all the vital capabilities required should it choose to develop its own future FEL facility, whilst simultaneously contributing to R&D on an international scale, such as at the European XFEL in Germany.”
CLARA’s first electrons were generated at around 4 million electron volts (MeV) and, over the next few months will go through a steady conditioning process, eventually ramping up to 50 MeV to be ready for use by the end of the year. It will also benefit from a new electron gun source that has been tested on VELA – another particle accelerator at Daresbury dedicated for research by industry. CLARA and VELA will be linked at source so that CLARA can also help support research on VELA. Once fully constructed CLARA will extend to 90 metres and its beam will reach a staggering 250 MeV – 99.99% of the speed of light! Its flexibility and tuneability means that it will be able to test out numerous FEL technologies for use in future FEL facilities, both in the UK and internationally.
Professor Susan Smith, Head of STFC’s Daresbury Laboratory, said: "This milestone is a fantastic achievement for all STFC’s scientists, engineers and collaborators who are working on CLARA. Reaching this milestone is confirming the UK's ability to build, develop and demonstrate its scientific skills and techniques in X-ray Free Electron Laser technology, which brings us exciting prospects for the future of next generation light sources. This is technology that will change people's lives for the better.”
Read further information about STFC’s Accelerator Science and Technology Centre.
Free Electron Lasers (FELs) are an increasingly important kind of light source. Standard lasers can be very bright sources of visible light but they soon fade away in the deep ultra-violet and x-ray regions of the spectrum. FELs represent a radical alternative to conventional lasers, being the most flexible, high power and efficient generators of tuneable coherent radiation from the infra-red to the X-ray. FELs can have the optical properties that are characteristic of conventional lasers such as high spatial coherence and a near diffraction limited radiation beam, but FELs combine a high energy electron beam and a magnet called an undulator in such a way that all of the electrons emit light of the same wavelength at the same time, producing huge bursts of light. The latest FELs produce pulses of X-ray light that are powerful and fast enough for scientists to take stop-motion pictures of atoms and molecules in motion.