What is cyclotron What is its principle


Structure and functionality The cyclotron is a circular accelerator that consists of two D-shaped chambers. An alternating acceleration voltage is applied between these chambers. Electrically charged particles pass through it again and again and can accelerate it further with each revolution because the particles are forced onto a spiral path by a magnetic field. The cyclotron can only be used with non-relativistic particles (therefore mostly protons, not electrons), because otherwise tactlessness occurs and the acceleration voltage no longer points in the right direction. Machines that compensate for this effect are called synchrocyclotrons. With them, the strength of the magnetic field changes over time. Other further developments of the cyclotron principle are used in the microtron and betatron.

How a cyclotron works.

The cyclotron frequency is the frequency with which an electrically charged particle makes its rounds in a cyclotron (or another uniform magnetic field). It results from equating the centrifugal force with the Lorentz force:

Development and use In 1930, Ernest Orlando Lawrence (1901–1958) proposed the principle of the cyclotron for the first time and at the end of the same year he had the first copy in his hands. It was around nine centimeters in diameter and accelerated protons to an energy of 80,000 electron volts.

The first circular accelerator: the cyclotron
Energies that can be reached in a cyclotron

Let us assume that the speed of the particles is still far below that of light. Then applies to the kinetic energy:

On the other hand, for the orbit of the particle, the Lorentz force and radial acceleration are in equilibrium:

For example, with a proton, a magnetic field of 1.6 Tesla and a cyclotron radius of 0.3 meters, this results in 11 million electron volts.