UCL Department of Physics and Astronomy

Dr Simon Jolly

Dr Simon Jolly

Associate Professor

Dept of Physics & Astronomy

Faculty of Maths & Physical Sciences

Joined UCL
1st Oct 2011

Research summary

I have two main research interests: plasma wakefield acceleration and proton therapy. The Advanced Wakefield (AWAKE) Experiment is a project at CERN to verify the approach of using protons to drive a strong wakefield in a plasma which can then be harnessed to accelerate a witness bunch of electrons. 

Plasma wakefield acceleration makes use of the sea of free electrons and ions within a plasma. A short incoming proton beam enters the plasma and attracts the free electrons to it; they accelerate towards it and overshoot. They are then attracted back to the region of positive charge, the ions, and again accelerate in and overshoot. These oscillating free electrons in the plasma create and accelerating electric field in the direction of the proton beam. Another witness beam of electrons can then be injected in the right phase behind the proton beam so as to be maximally accelerated through the plasma column. This results in accelerating gradients orders of magnitude higher than existing technology.

The AWAKE experiment will be carried out with the 400GeV CERN SPS proton beam. The experiment aims to accelerate 10-20 MeV witness electrons to over 1 GeV in about 5-10m of plasma. I lead the development of the electron energy spectrometer that will measure the energy of the plasma-accelerated electrons.

I am also leading the proton therapy research group within High Energy Physics. Proton therapy is a more precise form of radiotherapy that provides significant benefits over conventional X-ray radiotherapy. Protons deposit their dose in a much smaller region within the body: this leads to a more effective cancer treatment with a smaller chance of the cancer recurring. This is particularly important in the treatment of deep-lying tumours around sensitive organs, particularly for children whose bodies are particularly vulnerable to long-term radiation damage. The advantages of proton therapy, coupled to the reduced cost of the equipment, has led to a surge in interest in proton therapy treatment worldwide: the UK is currently constructing 2 full-sized proton therapy centres, to be based at UCLH in London and The Christie in Manchester and funded by the NHS. 

Treating these cancers requires machinery that is significantly more complex than a conventional radiotherapy system. In order to ensure that treatment with such complex machinery is carried out safely, a range of quality assurance (QA) procedures are carried out each day before treatment starts. The majority of this time is spent verifying that the proton beam travels the correct depth and is carried out for several different energies: these QA measurements of the proton range can take over an hour.  I am leading a project to develop detectors that can make faster and more accurate measurements of the proton range than existing systems. By using detectors developed within the High Energy Physics group, the measurement of the proton range for multiple energies would allow the complete morning energy QA procedure to be carried out in a few minutes, with an accuracy of less than a millimetre. 

Teaching summary

I am the course coordinator for PHAS3459, the third year Java programming course for physicists: "Scientific Computing with Object Oriented Languages". I help supervise two undergraduate lab courses: the general PHAS1241 lab course for first years and the PHAS2441 Electronics lab for second years. In addition I also supervise a number of MSci project students each year, primarily on projects related to my proton therapy and AWAKE research projects.


Other Postgraduate qualification (including professional), ATQ02 - Recognised by the HEA as an Associate Fellow |
Other Postgraduate qualification (including professional), ATQ01 - Successfully completed an institutional provision in teaching in the HE sector |
University of Oxford
Doctorate, Doctor of Philosophy | 2003
Brunel University
Other higher degree, Master of Physics | 1999


I was born in London but grew up in Basingstoke.  After 5 years of listless distraction at Cranbourne School and 2 years of A-levels at Queen Mary's College, I started a Masters in Physics at Brunel University in 1995. I graduated in 1999 with a 1st class honours degree but remained at Brunel, undertaking a PhD in Particle Physics, studying under Adrian McKemey. After a year however, I transferred to Exeter College, Oxford and started all over again studying accelerator physics with Phil Burrows. 

I spent the majority of my time at the Stanford Linear Accelerator Center in California, working on nanosecond-scale feedback systems and beam position monitors for the International Linear Collider.  I was delighted to be a founder member of the Feedback On Nanosecond Timescales collaboration and finally graduated with a DPhil in Particle and Accelerator Physics from Oxford in 2003: after a year in Margate designing X-ray test equipment and characterising scintillation materials for Hilger Crystals, it was clear that I couldn't really function in the real world and returned to academia in 2005, beginning a research associate position at Imperial College.  I remained at Imperial until moving to UCL to become a lecturer in Accelerator Physics in October 2011.

My main research interests lie in applications of particle accelerators. I am the leader of the UCL High Energy Physics proton therapy research group.  The NHS is currently building 2 proton therapy facilities in London and Manchester: to complement the existing ocular facility at the Clatterbridge Cancer Centre. Proton therapy is a more advanced form of radiotherapy that uses protons in place of X-ray photons: this means that tumours can be treated with much greater precision and significantly less damage to the surrounding tissue.  This is particularly valuable in children, whose bodies are still growing.  My research focuses on high precision detectors for proton beam Quality Assurance to ensure the treatment is delivered safely.

I am also a member of the international AWAKE collaboration that is seeking to develop proton driven plasma wakefield accelerators. Conventional accelerators are limited in how quickly a particle beam can be accelerated: beyond a certain point, the only way of making higher energy accelerators is to make them larger. However, it has been shown that plasmas can support electric fields several orders of magnitude higher than conventional accelerators. By using a proton beam to drive a wakefield within a plasma, this wakefield can in turn accelerate an electron beam to high energies in extremely short distances. The AWAKE experiment will use a 400GeV proton beam from the CERN SPS accelerator to drive a wakefield within a Rubidium plasma cell and accelerate electrons. I lead the development of the AWAKE spectrometer to measure the energy of these plasma accelerated electrons.

I have played American Football for Great Britain, captaining them in 1996, and also won national titles with Farnham in 1996, Oxford in 2001 and London in 2005.  I have also made a number of appearances on radio, television and at popular science events, but they were nothing to shout about.