The electron machine with many applications or electron model for many applications (EMMA) is a linear non-scaling FFAG (fixed-field alternating-gradient)

particle accelerator A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to very high speeds and energies, and to contain them in well-defined beams. Large accelerators are used for fundamental research in particle ...

Daresbury Laboratory Daresbury Laboratory is a scientific research laboratory based at Sci-Tech Daresbury campus near Daresbury in Halton, Cheshire, England. The laboratory began operations in 1962 and was officially opened on 16 June 1967 as the Daresbury Nuclear ...

in the UK that can accelerate

electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no kn ...

s from 10 to 20

MeV In physics, an electronvolt (symbol eV, also written electron-volt and electron volt) is the measure of an amount of kinetic energy gained by a single electron accelerating from rest through an electric potential difference of one volt in vacu ...

. A FFAG is a type of accelerator in which the magnetic field in the bending magnets is constant during acceleration. This means the particle beam will move radially outwards as its momentum increases. Acceleration was successfully demonstrated in EMMA, paving the way for future non-scaling FFAGs to meet important applications in energy, security and medicine. A linear non-scaling FFAG is one in which a quantity known as the

betatron A betatron is a type of cyclic particle accelerator. It is essentially a transformer with a torus-shaped vacuum tube as its secondary coil. An alternating current in the primary coils accelerates electrons in the vacuum around a circular path. Th ...

tune is allowed to vary unchecked. In a conventional

synchrotron A synchrotron is a particular type of cyclic particle accelerator, descended from the cyclotron, in which the accelerating particle beam travels around a fixed closed-loop path. The magnetic field which bends the particle beam into its closed p ...

such a variation would result in loss of the beam. However, in EMMA the beam will cross these resonances so rapidly that their effect should not be seen. EMMA will use the ALICE accelerator as a source of electrons and will be situated in the same laboratory at STFC's Daresbury site. EMMA is a proof-of-principle machine; the experience gained in building this machine will be useful for future

muon A muon ( ; from the Greek letter mu (μ) used to represent it) is an elementary particle similar to the electron, with an electric charge of −1 '' e'' and a spin of , but with a much greater mass. It is classified as a lepton. As wi ...

accelerators (which could be used in

neutrino A neutrino ( ; denoted by the Greek letter ) is a fermion (an elementary particle with spin of ) that interacts only via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass ...

factories), and also for

proton A proton is a stable subatomic particle, symbol , H+, or 1H+ with a positive electric charge of +1 ''e'' elementary charge. Its mass is slightly less than that of a neutron and 1,836 times the mass of an electron (the proton–electron mass ...

and

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with o ...

ion

s, which have applications for

cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...

therapy. Non-scaling FFAGs are a good candidate for use in an

accelerator-driven subcritical reactor An accelerator-driven subcritical reactor (ADSR) is a nuclear reactor design formed by coupling a substantially subcritical nuclear reactor core with a high-energy proton or electron accelerator. It could use thorium as a fuel, which is more abund ...

system in which a non-critical fission core is driven to criticality by a small accelerator. Future electrical power generation could be influenced heavily by the use power stations consisting of a sub-critical core containing a material such as

thorium Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Thorium is silvery and tarnishes black when it is exposed to air, forming thorium dioxide; it is moderately soft and malleable and has a high me ...

, and a small accelerator capable of providing extra neutrons via a spallation target. EMMA was funded by the BASROC consortium, under the CONFORM umbrella. Commissioning of EMMA began in June 2010 when the beam was injected and sent around part of the ring. Full ring commissioning commenced in August 2010. As of March 31 2011, full ring circumnavigation was completed to establish proof of principle.

References

External links

Nature Physics article

ASTeC project page

CONFORM – EMMA section

R. Edgecock et al., EMMA, The World's First Non-scaling FFAG. Proceedings of the 2008 European Particle Accelerator Conference
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Scientific publications relating to EMMA
Particle accelerators Research institutes in Cheshire Science and Technology Facilities Council {{accelerator-stub