A major milestone has been achieved in the completion of the U's next-generation particle accelerator, ALICE, which is set to produce an intense beam of light that will revolutionize the way in which accelerator based light source research facilities will be designed in the future.
ALICE is an acronym standing for Accelerators and Lasers In Combined Experiments. Financed by the Science and Technology Facilities Council with seed funding from the North West Development Agency, the project is designed to produce light from both the accelerator and advanced lasers that can be used simultaneously in cutting edge experiments.
ALICE is based at the Science and Technology Facilities Council's (STFC) Daresbury Laboratory and on Thursday 23 October, after more than four years of planning and construction, it achieved its first high-energy beam. This brings ALICE one step closer to its completion and to achieving its goal of energy recovery, a critical requirement for the economic viability of such future light sources.
Set to underpin the UK's next accelerator-based light source, ALICE is an R&D prototype whose cutting edge technology will enable advances in areas including security and medical imaging. ALICE produces terahertz radiation which can be used to significantly enhance airport security due to its ability to detect bombs and non-metallic items through clothing that would normally only be possible with a personal search, as well as providing significant potential for non-invasive medical imaging. High energy beams from ALICE will also go on to be used to influence technology for new cancer treatements in a linked project known as EMMA.
The first high-energy beam was achieved using ALICE's photoinjector, which fired a beam of electrons into a superconducting linear accelerator, creating a particle beam with a total energy of nearly four and a half million electron volts. The photoinjector is a high-brightness electron gun capable of generating extremely short pulses of electrons, less than a hundred picoseconds in duration (one picosecond is a millionth of a millionth of a second). These pulses are fired into the first linear accelerator (known as the booster) at a rate of 81 million shots per second. The booster is maintained at a temperature of -271 degrees Celsius, at which temperature it becomes superconducting and capable of sustaining very high electric and magnetic fields. This accelerated beam will eventually be used to generate pulses of infrared, ultraviolet and x-ray light, creating the ultimate stroboscopic light source capable of making real-time movies of chemical reactions at the atomic level. This capability will have a major impact in research carried out in the fields of drug development, materials science and 'green' technologies.
Susan Smith, Head of the Accelerator Physics Group at Daresbury Laboratory said: "This is a significant milestone towards ALIC'Es main target of demonstrating energy recovery. Energy recovery means that the energy used to create the beam is recovered and re-used after each circuit of the accelerator, so the best beams of light scientists will ever have used can also be produced most cost-effectively. Achieving the first high-energy beam is a significant step forward for the scientists and engineers at STFC Daresbury Laboratory who can now move on to commissioning the full accelerator system and demonstrating energy recovery."
