The cyclotron it is the simplest of the accelerators in use today. Particles such as protons or atomic nuclei are injected into the centre of two "D" shaped hollow conductors called "dees". They are subjected to a magnetic field perpendicular to the plane of the particle's motion and accelerated across the space between the Dees by a varying electric field – it changes polarity each half circuit of the particle, with each dee becoming positive then negative then positive polarity and so on, ensuring the particle is always accelerating..
The magnetic field keeps the particles moving in a circle as they move within the dees. The particles experience a magnetic force
to oppose the centrifugal force
Equating these:
The above equation implies that as the particles accelerate so that as
increases,
increases so that the particles move in a circle of larger radius.
The particle gains energy each time it passes through the gap between the dees, and after it has gained enough energy it is ejected to the target. A cyclotron can generate up to 10 MeV(Million electron Volts) of energy.