1. FFAG Fixed Field Alternating Gradient synchrotrons, FFAGs, combine some of the main advantages of both cyclotrons and synchrotrons:  Fixed magnetic field – like a cyclotron - fast cycling - high acceptance - high intensity - low beam loss and activation - easy maintenance - high reliability  Strong focussing – like a synchrotron - magnetic ring - lower cost than a cyclotron - beam extraction at any energy - higher energies or ion acceleration These advantages have created a great deal of interest in FFAGs over the last few years, though most of this has been in Japan. One of the electron model FFAGs constructed by MURA in the 1960's. Accelerator Science is generally associated with large-scale international projects and facilities dedicated to fundamental particle and nuclear physics experiments. However, it is now evident that electron, proton and heavy ion beam accelerators will develop additional and increasingly important roles in all aspects of science, technology, and medicine, with applications ranging from the therapy of advanced tumours, the production of radio-pharmaceuticals and medical isotopes, through ion implantation to the provision of secondary neutron and muon beams for probing the structure and dynamics of materials. Indeed, the growing number and wider diversity of potential particle accelerator applications demands nothing less than a paradigm shift in accelerator technology, in which the essential focus must turn from conventional extremely large and expensive multi-purpose facilities to compact, relatively cheap, but appropriately powerful single-purpose accelerators. It is also evident that a simple revamping of conventional linear accelerators, synchrotrons and cyclotrons will not satisfy the extreme demands for high beam power, high duty cycle or repetition rates with constraints on cost, size and simple, maintainable operation demanded by potential users of the new technologies. In recent years, a new type of accelerator has emerged: a Fixed Field Alternating Gradient synchrotron (FFAG), with most of the work taking place in Japan and, more recently, North America. The properties of these machines are such that they could enable this paradigm shift in accelerator-driven science. One application in which these FFAGs have enormous potential is hadron therapy, using beams of protons, carbon ions and even neutrons. In the UK, we plan to take the first steps to demonstrate that the most recent development of this novel accelerator technology is feasible and to learn how it could be applied to these applications. In the process, we also aim to redress the technology gap that has developed in this field between Europe and North America and Japan. A Paradigm Shift in Accelerator Technology ? The ISIS rapid cycling synchrotron at the Rutherford Appleton Laboratory. The 1MW cyclotron at the PSI Laboratory in Switzerland. Following from the discovery of strong focusing in 1952, FFAGs were proposed independently by Tihiro Ohkawa in Japan, Keith Symon in the US and Andrei Kolomensky in the USSR. The most extensive work was carried out by Symon and others at MURA (the Mid-Western Universities Research Association) in Wisconsin and a number of low energy electron models at around 50 MeV were constructed in the 1960's. However, proposals for proton FFAGs were not successful at that time, nor in the 1980's when 1.5 GeV machines were proposed for spallation neutron sources by the Argonne and Jülich Laboratories. A bit of history … Motivated mainly by the requirements of accelerators based on muon storage rings, in particular a Neutrino Factory, FFAG studies re-started in Japan in the late 1990's and resulted in the construction and testing of the first ever proton FFAG in 2000. This was the 500 keV Proof-of-Principle machine, which, as the name implies, was used to demonstrate the feasibility of this type of accelerator. With the successful test of this machine, a higher energy FFAG was also constructed at KEK, a 150 MeV proton FFAG, and first tested in 2003. This is a prototype for a cancer therapy FFAG. The first proton FFAG ever built: the 500 keV PoP at KEK. Many applications of FFAGs are being studied world-wide……… in particular, hadron therapy Due to the advantages listed above, FFAGs have the potential to bring a sea change to future accelerator technology. A 150 MeV proton FFAG built at KEK in Japan in 2003. FFAG F ixed F ield A lternating G radient Synchrotrons A new type of particle accelerator - with a wide variety of applications Introduction and Current World Status EMMA Two further FFAGs are building built in Japan:  A series of 3 FFAGs at the Kyoto University Research Reactor Institute as a prototype for an accelerator driven sub-critical reactor facility  PRISM: an FFAG being built in Osaka University for measuring some fundamental properties of muons ….and many are being studied:  A complete proton therapy centre in the Ibaraki Prefecture  At Mitsubishi Electric:  a prototype electron FFAG for radiation therapy, CT-scanning and industrial irradiation  a prototype carbon ion therapy facility  a prototype proton therapy facility using super-conducting magnets  A prototype carbon ion therapy facility at NIRS in Chiba  An FFAG for making thermal neutrons for Boron Neutron Capture Therapy at Kyoto University  eFFAG: a prototype electron FFAG for industrial irradiation and sterilisation A prototype 1 MeV electron FFAG at Mitsubishi. A magnet from the injector FFAG in Kyoto University. The three FFAG rings of the Chiba ion therapy facility. Magnet coils (left) and an RF cavity core for the PRISM FFAG in Osaka University