Particle accelerators are highly complex machines that take the smallest components of matter, charged particles, and boost them to velocities very close to the speed of light. Beams of these particles can be collided, and in the collisions strange new particles emerge. By analysing the resulting new particles, we can learn more about the structure of the universe itself.
Particle colliders tend to be very big, at 27 km in circumference the Large Hadron Collider is the largest machine ever built. However, smaller accelerators can be produced which have applications closer to home such as in archaeology, zoology and medicine.
Our group forms part of the John Adams Institute for Accelerator Science, a joint collaboration of the University of Oxford, Royal Holloway, University of London, and imperial College London. We work in close collaboration with our partners in the JAI as well as other institutions around the world.
We are working on the next generation of high energy colliders, both linear with the ILC and CLIC, and circular with the FCC. These so called Higgs factories will collide beams of electrons and their antimatter cousins positrons, in order to provide a detailed probe of the properties of particles such as the Higgs boson. Our group is helping to design these new facilities, working on beam optics, feedback systems, and beam orbit correction with the goal of increasing the luminosity as much as possible. In particular, we lead developments on the prototype ILC/CLIC final-focus system deployed at the KEK Accelerator Test Facility (ATF2) in Japan.
The technology that we have helped to develop to make these colliders a reality is already being used worldwide. Our group works with collaborations such as CERN’s Xbox and CLEAR groups to explore future uses of this technology.
Plasma wakefield accelerators
One challenging area of research is to use plasmas to create highly compact particle accelerators. Our group has made key contributions to the field, particularly in the use lasers to excite plasma waves in order to accelerate electron beams high energies in just a few mm.
We are also involved with AWAKE collaboration at CERN which uses proton beams to drive plasma waves and accelerate electron beams.
A compact accelerator could also require a compact way of focussing the beam. For this purpose we are looking at ways to use plasma lenses to focus and control charged particle beams.
Particle beam therapy
Our particle beam therapy group uses experience built up on high energy accelerators to develop the next generation of radiotherapy machines. We are developing the use of proton beams and Very High Energy Electron beams for this purpose as well as dosimetry techniques to measure the beams. Particular focus is on understanding the so called FLASH effect and how to exploit it clinically.
One key problem our group is working on, is to extend radiotherapy technologies to low and middle income countries. We are co-leaders of the Innovative Technologies towards building Affordable and equitable global Radiotherapy capacity (ITAR) initiative.
High intensity particle beams are required in a number of applications. However, when a large number of particles are confined within an accelerator, the forces between these particles can lead to particle losses. We are looking at ways to model these beams, both in simulation and experimentally using a linear Paul trap, known as the Intense Beam Experiment (IBEX) in order to better understand these processes and mitigate their effect.